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Heat treatment of Lignin Electro-spun Carbon Nano-Fibers Rey, Delphine 2017-04-06

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 1   Abstract—The electrospinnability of lignin with the help of  Polytheylene oxide, to produce electrospun carbon nanofibers, used for electrodes of various energy storage devices, is seducing the scientific community for its abundance, renewability, cost and the simplest, industrially scalable process. As for each and every technical lignin available in nature, the native lignin used here is the least energy consuming. A detailed, reproducible method is recorded, and a personalized heat treatment following electrospinning is produced to present the best conductivity of the electrospun carbon nanofiber. Further analysis and applications of the electrodes produced from these nanofibers are investigated. A promising upgrade seeks to filling the many pores in the fibers produced to increase the capacity of the electrodes crafted from these carbon nanofibers.    Index Terms— batteries, Carbon nanotubed, conductivity, electrode, electrospinning, electrospun carbon nanofibers, graphene, lignin, polymer, supercapacitors.  I. INTRODUCTION IGNING is the second most abundant biopolymer on the Earth after cellulose. It is found in plants and becomes a waste byproduct of the gigantesque pulp and paper industry - burnt as fuel to power the very industry that produces it. This renewable biopolymer’s potential has been underestimated long enough. Along with centuries-old electrospinning techniques that are simple and scalable to industrial production, the birth of renewable electrospun carbon nanofibers (ECNF) from lignin solutions brings a new wind of innovation in the field of batteries, super capacitors and other energy storage devices. Their free-standing, flexible architecture, enhances their implementation as electrodes in wearable electronics. These ECNFs must undergo a specific heat treatment before they can be used as performant, highly porous electrodes, and even separators, inside energy storage devices. The procedure transcribed here details reproducible steps but also interprets the effect of various heat treatment profiles on the conductivity of the ECNF electrodes. The native lignin used is particularly interesting relative to other types of technical lignin byproducts because these go through an energy and time consuming fractioning process in order to separate various molecular weights of different technical  Submitted Thu April 6th 2017.  D. R. Author is an undergraduate student of ELEC 496: Undergraduate Thesis of Electrical and Computer Engineering in the Faculty of Applied Science at the University of British Columbia, Vancouver, BC V6T 1Z4 Canada (e-mail: dmfrey3@  lignins. Native lignin is therefore a more environmentally friendly alternative to current battery electrodes. II. BATTERIES Luigi Galvani first demonstrated a frog’s muscle contracting when two different metals would come in contact through the intermediary of the frog’s nerve back in 1791 [12]. Alessandro Volta studied the phenomenon until, in 1800, he introduced the Volta pile as the first electrochemical device of its kind [12]. It consists of a pile of layers of zinc, salt water and silver producing an electrochemical flow of electrons. Soon Leclanché’s battery electrolyte was replaced by a gel, thus facilitating transport [12]. Yet these batteries were exhaustive. The scientific and civilian community had to wait until 1859 for Gaston Planté to introduce the first rechargeable lead-acid battery [12]. Alkaline rechargeable batteries were then born in 1899 from W. Jungner’s efforts [12].  With more than 100 possible electrochemical systems to date, all batteries are made of and electrolyte sandwiched between and oxidizer and a reducer producing a flow of electrons, hence a current [12]. The Lithium ion rechargeable batteries lead the competition but concerns arise when the theoretical limit of the device is reached. This limit does not support the full extent of the expectations for the applications Lithium ion batteries are designed for [4]. In addition, the Lithium available on Earth cannot quench the demand for Lithium ion rechargeable batteries, even at theoretical performances. Potential predecessors to the current Lithium ion battery include Lithium Sulfur, Lithium air and Sodium ion batteries [12].   In 2001, the battery industry was worth USD 48 billion per year and rising thanks to its versatility despite the introduction of electrical grids in the civilian infrastructure [12]. The procedure presented here aims to develop sustainable electrodes for such batteries from renewable lignin-based ECNF described below.  III. LIGNING Lignin chains are the building blocks of wood and plants [13]. The plant-derived biopolymer provides structure for the plant and is known as “native lignin” [13]. After processing in pulp and paper bio-refineries, lignin takes various forms including Organosolv and Kraft Lignins [13]. Until this day, the 50 million yearly tons of Lignin most often finds itself combusted as a fuel to provide energy for the very industry that produced it: the paper industry [6][13]. It is also used in packing materials [13]. Bulk lignin also has attributes in medicine for its anti-oxidant, antiviral, antitumor and Heat treatment of Lignin Electro-spun Carbon Nano-Fibers Delphine Rey, Undergraduate student, UBC L  2 anticarcinogenic properties. Lignin also finds itself in agriculture: both livestock’s stomachs and in fertilizers [6][13].  Despite a wide range of applications, Lignin’s abundance - as second largest source of organic material – really remains a by-product of the pulp and paper industry [13]. Lignin therefore becomes source of attention when its biodegradability, low toxicity, and low cost scream sustainability [13]. However, Lignin lacks mechanical advantages with wearable electronics in mind [8]. Nevertheless, it is a suitable candidate to replace today’s favorite: polyacrylonitrile (PAN). PAN is non-renewable and expensive [8]. Other carbon precursor source like husk rice or sugar are not freestanding like ligning based ECNFs and can be complicated to process into a nanofiber [6].  IV. ELECTROSPINNING The electrostatic spinning process is suited to produce large quantities of nanofibers from polymer filaments using an electrostatic field [9]. As a result, this simple method is scalable to industrial production standards [4][6]. This technique also allows doping the fiber with agents. The doping agents are carefully selected to enhance charge transport by transforming the energy gap of the electrospun fiber [4]. Fig.  1. pictures the equipment set up and the production of electrospun carbon nanofiber. A syringe with a spinneret nozzle contains a viscoelastic fluid [3]. The solution consists of N,N-Dimethylformamide (DMF) used to dissolve Polytheylene oxide (PEO) and Lignin together. PEO enhances fiber formation of biopolymers during electrospinning [7]. It is extensively used for its unique viscoelastic properties [3]. Without PEO, Lignin solutions resulted in poor electrospinnability (i.e.: electrospraying, described later) [2]. The metallic nozzle is separated from a collecting surface by a strong electric field. The droplet of polymer solution pushed out the nozzle feels a charge induced on its surface until the surface tension and viscous forces of the viscoelastic fluid are overcome. At this point, the drop is pulled into thin air by the electric field, forming a Taylor cone. The jet of nanofiber produced travels towards the grounded collector where is it accumulates [3]. The solvent in the solution evaporates as the droplet is elongated before it is collected [9].  Mass production electrospinning devices, however, place the syringe of polymer solution and the metal collector vertically so gravity works against electrospraying [11]. Electrospraying occurs when the solution is not elastic enough, prohibiting the droplet from elongating into a nanofiber. Instead, the droplet is ejected and splattered on the metal collector, thus ruining the chance of producing a well woven ECNF mat.     Fig.   1  Electrospinning device and resulting nanofibers [9] The careful balance between viscoelastic properties and the electric field the polymer solution feels is specifically tuned by optimizing the applied voltage and the distance from the collector, the flow rate of the syringe pump, the nozzle diameter but also on the properties of the polymer solution used. It’s conductivity, density and viscoelastic properties strongly affect the resulting ECNFs [3]. The ultimate trade off takes place between the stability of the electrospinning process and smallest fiber diameter achievable (i.e.: highly porous ECNF with large surface area) As a result, electrospinning provides means to produce tunable fiber morphologies, large surface area and charge transport for electrochemical processes. Doping the fiber was already mentioned but heterostructures can also be electrospun by embedding active materials such as Carbon nanotubes (CNT) or graphene on the ECNF mat [9][4]. The free-standing architecture produced is also very attractive for flexible solar cells and wearable electronics [2]  V. HEAT TREATMENT The mat of ECNF produced by electrospinning is not ready for electrode fabrication and battery assembly. The following heat treatment necessary takes place in two parts: stabilization and carbonization. This report focuses on tuning the stabilization and carbonization heat treatments to native lignin and such calibration must be performed for each technical lignin mentioned earlier. A. Stabilization The first heating profile uses relatively low temperature and ramping rate compared to the following carbonization process [4]. Stabilization essentially prepares the ECNF for the following carbonization process by crosslinking the fibers [8]. The fiber is transformed through a variety of complex physical and chemical reactions to avoid the fibers from fusing together during its carbonization [4]. B. Carbonization The stabilized ECNF is now heated rapidly to significantly higher temperatures in inert atmosphere. The aim is to remove Hydrogen, Oxygen and Sulfur atoms – thus shrinking the fibers’ diameter - as well as to evolve the structure of the fiber from a ladder like skeleton into a graphitic configuration by fusing the crosslinked fibers [2][4][8]. The heating profile also involves smoothing of the fiber but also reducing their  3 diameter, resulting in increased surface area and thus conductivity of the thermally treated ECNF. The increased conductivity can also be explained by the greater connectivity as a result of fusing the crosslinks, thus providing numerous pathways for current flow [8]. The solution preparation, electrospinning and heat treatment can now be enunciated.  VI. PROCEDURE A. Ingredients 1) Native Lignin provided by FP-Innovations 2) Polytheylene oxide (PEO) with molecular weight of 900,000 provided by Signma-Aldrich 3) Spectroanalyzed N,N-Dimethylformamide (DMF) provided by Fisher Scientific 4) Nitrogen gas 5) Silver paint (fast drying) B. Apparatus 1) Sartorius CPA225D microscale 2) Cole-Parmer StableTemp Vacuum Oven Model 282A 3) Sonics Vibracell tip sonicator 4) Cole-Parmer StableTemp magnetic vortex stirrer 5) KatoTech Co.Ltd. NEU Nanofibre Electrospinning Unit 6) Syringe pump (10ml and Luer-Lok tip) 7) Blunt-tip stainless steel needle (10 gauge) 8) Whirlpool Gold Accudry Dehumidifier 9) Aluminum Foil, tape, paper towels, cutter, scissors 10) Thermoscientific Thermolyne Eurotherm 2116 Furnace 11) Controllable gas input 12) Mineral oil bubbler 13) Tektronics Precision Multimeter 14) Marathon Electronic Digital Caliper Range: 0 to 12”/0 to 300nm C. Method 1) Prepare the sample solution to electrospin a. Dry the native lignin in a vacuum oven at 50 °C for 24 hours. b. Weigh 6g of DMF using a metal spatula into a glass vial and 4g of DMF in another glass vial, both sealed with an air-tight cap. c. Weigh 30% of the total amount of DMF ( 0.3(6+4) = 3g) of lignin with a metal spatula into a glass vial with an air-tight cap. d. To produce a 99/1 lignin/PEO sample, weigh out ( 0.99x0.1/3 = ) 0.03g  of PEO in a glass vial. e. Place the pebble of the magnetic stirrer in the vial containing 6g of DMF, all onto the 80°C plate of the magnetic stirrer and increase the magnetic stirring intensity to a stable and safe maximum. f. Gradually introduce the lignin powder so to dissolve it completely without forming clumps on the side walls of the vial. g. Every minute, use the vortex mixer for 5 seconds, for a total of 30 minutes.  h. Ultrasonicate the sample with a pulse of 5 seconds for 30 minutes.  i. In the meantime, repeat steps e. with the vial of 4g of DMF through g. with the PEO sample.  j. Gradually introduce the DMF and Lignin solution using a glass pipette into the DMF and PEO solution while magnetically stirring at 80°C.  k. Magnetically stir the resulting DMF, Lignin and PEO solution for 1 hour.  2) Electro-spin the sample a. Check the electrospinning chamber is clean. b. Start the dehumidifier on an automatic fan and continuous run for 28-35% humidity and place it perpendicular the open window behind the cylindrical rotating drum of the electrospinning device to avoid significant turbulence within the electro-spinning chamber. c. Transfer the DMF, Lignin and PEO solution into the syringe and remove any air bubbles. d. Cover the target drum with the shiny side of aluminum foil facing the syringe (tape the foil and rotate the drum so the tape faces the syringe as it becomes a sacrificial area for  imperfect electrospinning at the beginning).  e. Cover the area between the syringe and the target drum with paper towels and tape to protect the equipment from stains due to splashes of DMF, Lignin and PEO solution. A picture is available in the appendix. f. Secure the syringe in the  allocated slot tightly and fix needle with a circular antenna used to focus the electric field from the tip of the needle towards the drum. A picture is available in the appendix. g. Fix the pump onto the syringe, 17cm away from the drum. h. Check the sweeping mechanism is centered and narrow. i. Close the front window once the apparatus is set up. j. Turn on the applied voltage and increase it to 1 = 17 kV. k. Turn on the syringe pump at a rate of  0.145 ml.min-1. l. Turn on the traversing speed to 1 cm.min-1. m. Turn on the drum target speed to 1m.min-1 once a stable fiber exits the syringe by (adjusting the parameters might be required). n. Check the quality of the fiber by carefully opening the front window to avoid turbulence inside the electro-spinning chamber. Do not place hands between the syringe and the target drum. Use a wood stick with a glass slides taped on its end and collect fiber just in front of the drum target before slowly closing the window and removing the slide from the wood stick to inspect under a microscope.  o. Turn off the sweep, the pump, the field and the target spin and the dehumidifier.  4 p. Release and remove the syringe and the antenna. q. Repeat step 1) and 2) a., b., e. and h. to o. to produce a 2nd layer and hence a thicker fiber. r. Cut the aluminum foil with the fiber where the foil was tapped and seal it in a labeled plastic bag for each sample.  s. Remove the protective paper towels taped and clean the chamber from residual fibers with paper towels.  3) Perform the heat treatment on the ECNF a. Calibrate and tune the furnace once. b. Slide each 10cm section of the furnace tube prior to each treatment 5min at 700°C. c. Use an air jet to get rid of residue in ceramic plugs prior to each treatment. d. Use an electric polisher to polish off residue from the sample steel frames prior to each treatment. e. Cut a sample of ECNF on the aluminum sheet to the size of the sample frame (with minimum contact on the surface of the fiber). f. Carefully peel the layers of fiber off the aluminum foil to secure it in between each steel frame. A picture is available in the appendix g. Place the framed sample into the furnace’s quartz sample boat. h. Carefully slide it in the measured center of the furnace. i. Plug the tube with the ceramic plugs and seal it with open valves carefully so to avoid toppling the sample in the tube. j.  Stabilization: i. connect the valve with a pressure gauge to a drain tube applying a negative pressure. ii. Turn on the furnace. iii. Under the Home list, set the set point SP = 250 °C and  iv. Under the SP (set point) list, set the set point rate limit SPrr = 2 °C.min-1, the dwell time dWell = 120 min and the timer operating mode tm.OP = OPT.1 (this option is described later).  k. Carbonization: i. when the stabilization of the fiber comes to an end, close both valves. ii. Connect the valve with the pressure gauge to the vacuum pump and carefully open it (to avoid rapid changes in build-up pressure release) until the furnace reaches a stable negative pressure. iii. Close the gauged valve and stop the vacuum pump.  iv. Switch the connection of the gauged valve from the vacuum pump to the positive pressure mineral oil bubbler. v. Release the nitrogen gas tank valve to fill the connection tube with nitrogen flowing out. vi. Connect the nitrogen tube to a flow regulator set on its minimum, in turn connected to the furnace’s other valve.   vii. Open that valve carefully (to avoid build-up pressure release) until atmospheric pressure is reached inside the furnace tube before carefully opening the gauged valve (to avoid sucking oil from the bubbler up, into the tube and furnace). viii. Increase the flow of nitrogen to produce 2 bubbles per second in the mineral oil bubbler.  ix. Increase the set point, SP = 900c°C. x. Increase the set point rate limit to  SPrr = 5 °C.min-1. xi. Increase the dwell time to dWell = 300 minutes. 4) Two point probe method: a. Cut out a 3mm wide strip of ECNF onto a glass slide. b. Silver paint perpendicular lines over the ECNF strip and onto the slide. c. Place in glass petri dish over 50 °C hot plate for 5 minutes. d. Measure and record the sample strip’s length, width and its thickness with a digital caliper. Measuring the length requires taking the smallest distance between each silver lines as it is the shortest path the current will flow through e. Measure the resistance using an ohmmeter, across each pair of silver paint lines. A picture is available in the appendix. f. Repeat the measurement for each nearest pair of silver paint lines as the strip is divided into half and then quarters with silver paint (breaking the sample down isolates major cracks in the fiber due to mishandling which significantly decreases the conductivity of the overall sample). The dimensions and resistances collected can be processed as described in the Results section..  5 This report aims to vary the temperature profiles used during the stabilization and carbonization heat treatments as laid out in Table.  I. The set point temperatures, set point rate limits and dwell times were adjusted around previously optimized values corresponding to similar ratios of Kraft lignin [1].  The timer operating mode was set as option 1 in the heat treatment procedure. This profile represents the temperature curve displayed in Fig.  2 below.   Fig.  2. Timer Operating Mode : Option 1 [14] However, the carbonization following the stabilization was performed when the stabilization profile reaches the standby mode, before it cools down. The resulting graph in Fig.  3 shows a consecutive 2 step increase in temperature. The reason being that successive heating conserve energy and saves time during large scale manufacturing.   Fig.  3. Heat Treatment Temperature Profile [1] VII. RESULTS The ECNFs were successfully electrospun, though some droplets -  due to poor parametrization - are present, as well as beads stuck to the fiber– due to humidity. These were observed over the microscope as seen in Fig.  4 and Fig.  5 [1].   Fig.   4. 1st layer of ECNF  Fig.   5. 1nd layer of ECNF  20                                                                                     Part Number HA026270    Issue 5.0    Aug 07  3.11 To Use The Timer • Press  until you reach the SP list • Press  until you reach the tM.OP parameter • Press  or  to select the timer operating mode, Opt.1 to Opt.5 as follows:  3.11.1 Opt.1 - Mode 1, Dwell and Switch Off            In reset In reset, you can switch between automatic control and standby mode, using the parameter m-A in the HOME list. The controller is supplied with the m-A parameter hidden.  You must first reveal it.  See ‘To Hide, Reveal and Promote Parameters’.              Standby mode Temperature Setpoint Reset Timing Running EndEnd flashes Waiting to reach temperature  Auto     m-A From the HOME display press  until the m-A parameter is displayed.  Press  or  to select:  Auto  Automatic control mAn  Standby mode. (the MAN beacon below OP2 will illuminate) Press  and   together to return to the HOME display a soaking time of 12 hours was necessary to remove the all of the PEO from thesurface of the fibres and that soaking for longer than this did not contribute to ad-ditional mass loss from the fibres in a significant way. The fibre mats were thenremoved from the water and dried on a stainless steel rack in a vacuum oven at50C for 12 hours.4.1.4 Stabilization and CarbonizationFigure 4.1: Graphical representation of the stabilization and carbonizationprocess.In order to convert the electrospun fibres into conductive carbon nanofibres,fibre mats were placed on stainless steel racks in a Thermo Scientific F21135 fur-nace, with a controllable gas input and a mineral oil bubbler to regulate positive48TABLE I HEAT TREATMENT PARAMETERS  Stabilization Carbonization Sample # SP SPrr dWell SP SPrr dWell 1 250 1 120 900 5 300 2 240 1 120 900 5 300 3 260 1 120 900 5 300 4 250 2 120 900 5 300 5 250 1 180 900 5 300 6 250 1 120 900 2.5 300 7 250 1 120 900 5 150 8 250 1 120 900 5 450                          6  The 6 parameters of set point, set point rate limit and dwell time for each stabilization and carbonization heat treatment were assumed to behave as independent variables.   The data collected includes measured resistances and dimensions listed in tables for each sample in the appendix. The conductance of the samples were calculated and normalized using (1) with s representing conductivity measured in  Ω"#𝑚"#	or 𝑆 ∙ 𝑚"#, L: length, t: thickness and width in mm and R as electrical resistance in Ω using the 2-probe method. 𝜎 = *+,- (1)  Table.  II presents the average of the conductance of each segment as well as the best conductivity found in a single segment. Increased conductivity relative to the 1st reference sample was highlighted in green, else red.  The results demonstrate that the effect of varying the temperature profiles vary significantly from Kraft lignin. Despite the many carbonization temperatures tested in [1], these values must now be re-evaluated. Increasing the temperature of stabilization from 250 to 260 ºC produced by far the most conductive samples. This large increase demands further investigation for an optimized stabilization temperature. Increasing the dwelling time during the stabilization from 2 to 3 hours has not proven significant changes in conductivity. Further inquiry might not necessarily prove useful, by the law of diminishing returns, to sustain high temperatures over long periods of time. However, lowering the set point rate during carbonization from 5 to 2.5 ºC has revealed poorer conductivity, therefore an increase in set point rate to 7.5 ºC should be performed and reiterated for values pointing to better conductive performances. Finally, increasing the carbonization dwelling time from 5 to 7.5 hours significantly increased the conductivity of the sample. Perhaps investigating longer carbonization times will not lead to an increase in conductivity significant enough to convince the production of Lignin-based ECNF to carry carbonization heat treatment at 900 ºC for extended periods of time. VIII. FURTHER ANALYSIS The heat treated ECNF produced can be further analyzed and characterized for morphological and structural properties through Scanning Electron Microscopy (SEM) techniques and x-ray diffraction analysis [2][1].  Specific surface area can be  measured by Nitrogen sorption [1][2]. Total pore volume and average pore size and pore size distribution can also be estimated [2]. The molecular composition of the ECNF is revealed by Raman spectroscopy and thermogravimetric analysis (TGA) [1].  Once the electrodes are punched out of the thermally treated ECNF mat, they will be assembled in a home made battery cell with a separator and electrolyte as represented in Fig.  6 and pictured in Fig.  7, further test can be carried out to evaluate the overall performance of the resulting battery prototype test cell.  Fig.   6. Electrochemical battery cell cross section schematic [1]  Fig.   7. Disassembled electrochemical battery cell Cyclic voltametry (CV) studies the capacitive behavior of the test cell [2]. Galvanostatic (dis-)charge provides an estimate of the cycling life of the battery. Finally, Electrochemical Impedance Spectroscopy (EIS) reveals the charge transfer and resistance properties of the electrode material [1][2].  With this information, the fibers’ performance as electrodes in a prototype cell can be better evaluated for different electrode purposes. IX. FURTHER APPLICATIONS ECNF can be tailored for applications in electrical conversion systems through their structural, electrical, optical and thermal properties. They include fuel cells, dye-sensitized solar cells (DSSC) and quantum-dot sensitized solar cells (QDSSC) [4].  ECNF deserve an attempt to replace the expensive and scarce platinum (Pt) used in highly efficient DSSCs or QDSSCs and even fuel cells. The current Lithium ion batteries can be updated with ECNF electrodes - resulting in large 5.1.2 El ctrod PreparationCircular electrodes were stamped from as-carbonized sheets of ECNFs using agasket punch set purchased from General Tools Mfg. Co. and were 6mm in di-ameter. The mass of the circular ECNFs electrodes was measured with a SartoriusCPA225D semimicro balance. A Celgard 2500 m cr por us membrane was usedas a separator and was stamped into circular pieces of 8mm diameters. Electrodesand separators where then soaked in electrolyte for at least 6 hours prior to electro-chemical testing. 6M KOH electrolyte was prepared by adding KOH Pellets to theappropriate amount of DI water and stirring for at least 1 hour.5.1.3 Test Cell FabricationFigure 5.1: Sche atic representation of the electrochemical testing cell.Two-electrode cells were put together in a lab-designed testing cell (Fig 5.1)that included two stainless steel columns as current collectors surrounded in a PFAair-tight casing. Two electrodes were placed between the two current collectors73TABLE II AVERAGE CONDUCTIVITIES Sample # Average conductivity, 𝜎 in 𝑆 ∙ 𝑚"#  Best conductivity, 𝜎 in 𝑆 ∙ 𝑚"# 1 0.59 0.87 2 1.37 1.63 3 1.33 1.77 4 25.10 35.2 5 0.72 0.81 6 0.41 0.54 7 1.29 1.95 8 6.39 7.21   7 energy conversion density and improved cyclical performance [4]. Doping the fibers also further increases these qualities [4]. Similarly, Lithium Sulfur batteries can also rely on carbon nanostructures to prevent high solubility of long-chain polysulfide ions. Furthermore, the carbon nanostructure allows for better electrical conductivity than Sulfur [4]. ECNF find themselves in Lithium air batteries as well (as catalysts) or in Sodium-ion batteries. All batteries, including the ones mentioned above, have in common a separator, an anode, cathode and electrolyte. The separator separates the anode and cathode physically, thus preventing short circuits through the electrolyte [5]. Today’s polyolefin micro-porous membrane have provided batteries the means of a separator but their poor thermal resistance compromises the safely and stability of the resulting batteries [5]. PAN membranes have proven superior in that regard. Their greater porosity also allowed for larger electrolyte absorption and surface area, in turn, increasing cycling capacity. Increased wettability also boosts the assembly of the batteries [5]. The simple and inexpensive preparation of ECNF separators therefore becomes very attractive.  Furthermore, supercapacitors formulate expectations to use these ECNF electrodes when graphene has outperformed itself in supercapacitors but with one inconvenient: clustering of graphene. Electrospinning a precursor solution with graphene remedies to the re-stacking of graphene and remain a free-standing electrode [4][2]. Supercapacitors are electrochemical devices capable of rapidly storing and releasing electrical charge at its electrode’s surface thanks to their exceptional surface area. Additionally, supercapacirors’s competitive cycle life and low discharging requires low maintenance in addition to being environmentally friendly, safe over a wide range of temperatures. They become therefore very attractive for applications requiring exceptionally fast charging like with portable electronics, memory back-up systems or hybrid cars [11]. Finally, the method used to produce photocatalysts must be attempted for electrochemical electrodes. It involves a gelation process for the dopant before it is mixed with a polymer precursor and dried. It is then dissolved into a solution for electrospinning before undergoing thermal treatment [10]. Although the dopant nanoparticles were much smaller than diameter of the spun fiber, this method provides a starting point to inlay ECNF nano-powder into the pores of the very same ECNFs. This technique is hopeful when, until now, soaking the thermally treated ECNF in a solution of ground ECNF particles has only proven surface penetration by the particles. As a matter of fact, ECNF serve as air and water filtration membranes [9]. X. CONCLUSION Filling the many pores of ECNF produced from Lignin by electrospinning provides hope to increase the low capacity of such cells using ECNF electrodes. This report did not mention electrospinning higher concentrations of PEO in the Lignin solution. The resulting increase in viscosity boosts the porosity of the ECNF after a hydrothermal treatment [1]. So once the thermal treatment of ECNFs is optimized for native lignin ECNFs, larger portions of PEO can be used to increase the porosity of the electrodes produced. The capacity of these electrodes can be heightened by filling the gap with the gelation of graphene nanoparticles into the electrospinning solution. Attempts to replace graphene nanoparticles with ECNF nano-powder can then be carried through. The resulting production of highly porous and performant electrodes from abundant, renewable and safe Lignin by a simple scalable electrospinning process brings new hopes for a sustainable future. One with the abundance of high capacity, cyclic ability and safe electronics, whether integrated in the civilian infrastructure, electric vehicles, on the go or as wearable electronics and photovoltaic devices. APPENDIX Results: A primary reference sample was attempted from a single layer of ECNF which failed during the heat treatment:  The tables of dimensions and resistance for each segment of each of the 8 samples produced are presented below with corresponding conductivities, including the average reported in Table.  II. The average conductivity omitted failed measurements highlighted in red. The best conductivity highlighted in green was also presented in Table.  II.   1st and reference sample stabilized at 250 ºC at 1 ºC/min for 2 hours:  Sample # 1 Segment L W T R 𝛔 1-5 26 4.58 0.12 60 0.788452208 1-3 9.5 4.58 0.12 25 0.691411936 3-5 10.83 4.58 0.12 40 0.492631004 1-2 1.13 4.58 0.12 inf 0 2-3 4.91 4.58 0.12 13 0.687213078 3-4 7.16 4.58 0.12 15 0.868510432 4-5 6.25 4.58 0.12 50 0.227438137 Average      0.59  8  2nd sample stabilized at 240 ºC:  Sample # 2 Segment L W T R 𝛔 1-5 43.11 2.92 0.08 132.00 1.40 1-3 21.70 2.92 0.08 57.00 1.63 3-5 19.25 2.92 0.08 62.00 1.33 1-2 9.53 2.92 0.08 28.00 1.46 2-3 7.47 2.92 0.08 23.00 1.39 3-4 8.23 2.92 0.08 23.00 1.53 4-5 7.02 2.92 0.08 34.00 0.88 Average 	    1.37  3rd sample stabilized at 260 ºC:   Sample # 3 Segment L W T R 𝛔 1-5 35.42 2.49 0.07 100.00 2.03 1-3 31.00 2.49 0.07 11.11 16.01 3-5 33.00 2.49 0.07 10.35 18.29 1-2 0.60 2.49 0.07 1.91 1.80 2-3 13.00 2.49 0.07 2.10 35.52 3-4 15.00 2.49 0.07 4.00 21.51 4-5 15.00 2.49 0.07 2.52 34.15 Average 	    25.10         4th sample with stabilization set point rate at 2 ºC/min   Sample # 4 Segment L W T R 𝛔 1-5 26.08 2.37 0.09 70.00 1.75 1-3 7.94 2.90 0.09 22.10 2.25 3-5 13.00 1.83 0.09 41.50 0.50 1-2 3.42 3.01 0.09 13.00 0.97 2-3 2.09 2.81 0.09 11.00 0.75 3-4 4.78 1.77 0.09 17.00 1.77 4-5 5.02 1.84 0.09 23.00 1.32 Average 	    1.33  5th sample with a stabilization dwell time of 180min:  Sample # 5 Segment L W T R 𝛔 1-5 31.82 3.11 0.12 165.50 0.52 1-3 15.51 3.11 0.12 77.00 0.54 3-5 14.52 3.11 0.12 88.00 0.44 1-2 7.01 3.11 0.12 47.50 0.40 2-3 5.73 3.11 0.12 32.00 0.48 3-4 12.39 3.11 0.12 100.50 0.33 4-5 3.07 3.11 0.12 44.00 0.19 Average 	    0.41     9 6th sample with a carbonization set point rate of 2.5 ºC/min:   Sample # 6 Segment L W T R 𝛔 1-5 40.14 2.69 0.16 71.00 1.31 1-3 18.82 2.69 0.16 350.00 0.12 3-5 14.26 2.69 0.16 17.00 1.95 1-2 8.67 2.69 0.16 28.00 0.72 2-3 6.63 2.69 0.16 11.00 1.40 3-4 5.12 2.69 0.16 6.60 1.80 4-5 5.96 2.69 0.16 8.20 1.69 Average 	    1.29  7th sample with a carbonization dwell time of 150min:  Sample # 7 Segment L W T R 𝛔 1-5 34.61 4.39 0.14 72.00 0.78 1-3 16.33 4.39 0.14 41.00 0.65 3-5 16.92 4.39 0.14 34.00 0.81 1-2 6.51 4.39 0.14 19.00 0.56 2-3 7.90 4.39 0.14 17.00 0.76 3-4 7.88 4.39 0.14 17.00 0.75 4-5 6.23 4.39 0.14 14.00 0.72 Average 	    0.72    8th sample with carbonization dwell time of 450min:  Sample # 8 Segment L W T R 𝛔 1-5 18.57 3.88 0.02 35.00 6.84 1-3 0.00 3.88 0.02 5.00 0.00 3-5 12.86 3.88 0.02 23.00 7.21 1-2 0.00 3.88 0.02 8.00 0.00 2-3 0.00 3.88 0.02 9.00 0.00 3-4 3.98 3.88 0.02 10.00 5.13 4-5 0.00 3.88 0.02 5.00 0.00 Average     6.39     10 The set up used during the electrospinning process is pictured below: Step 2) c. d.   Step 2) e.   Step 2) m.     Step 3) e. f.   Step 4) b. f.   REFERENCES [1] T. Watson, “Engineering High Performance Electrodes for Energy Storage Devices from Low-cost, Sustainable and Naturally Abundant Biomaterials,” M.S. thesis, ApSc, UBC, Vancouver, BC, 2017. [2] Lai, Chuilin, et al. "Free-Standing and Mechanically Flexible Mats Consisting of Electrospun Carbon Nanofibers made from a Natural Product of Alkali Lignin as Binder-Free Electrodes for High-Performance Supercapacitors." Journal of Power Sources, vol. 247, 2014, pp. 134-141, doi:10.1016/j.jpowsour.2013.08.082.Link [3] Aslanzadeh, Samira, et al. "Electrospinning of Colloidal Lignin in Poly(Ethylene Oxide) N,N-Dimethylformamide Solutions." Macromolecular Materials and Engineering, vol. 301, no. 4, 2016, pp. 401-413, doi:10.1002/mame.201500317.Link [4] Peng, Shengjie, et al. "Electrospun Carbon Nanofibers and their Hybrid Composites as Advanced Materials for Energy Conversion and Storage." Nano Energy, vol. 22, 2016, pp. 361-395, doi:10.1016/j.nanoen.2016.02.001.Link [5] Zhao, Man, et al. "An Electrospun lignin/polyacrylonitrile Nonwoven Composite Separator with High Porosity and Thermal Stability for Lithium-Ion Batteries." RSC Adv, vol. 5, no. 122, 2015, pp. 11115-1112, doi:10.1039/c5ra19371k.Link [6] Wang, Su-Xi, et al. "Lignin-Derived Fused Electrospun Carbon Fibrous Mats as High Performance Anode Materials for Lithium Ion Batteries." ACS applied materials & interfaces, vol. 5, no. 23, 2013, pp. 12275.Link [7] Dallmeyer, Ian, Frank Ko, and John F. Kadla. "Electrospinning of Technical Lignins for the Production of Fibrous Networks." Journal of Wood Chemistry and Technology, vol. 30, no. 4, 2010, pp. 315-329, doi:10.1080/02773813.2010.527782.Link [8] Dallmeyer, Ian, et al. "Preparation and Characterization of Interconnected, Kraft Lignin-Based Carbon Fibrous Materials by Electrospinning." Macromolecular Materials and Engineering, vol. 299, no. 5, 2014, pp. 540-551, doi:10.1002/mame.201300148.Link [9] Huang, Zheng-Ming, et al. "A Review on Polymer Nanofibers by Electrospinning and their Applications in Nanocomposites." Composites  11 Science and Technology, vol. 63, no. 15, 2003, pp. 2223-2253, doi:10.1016/S0266-3538(03)00178-7.Link [10] Nyamukamba, Pardon, et al. "Preparation of Titanium Dioxide Nanoparticles Immobilized on Polyacrylonitrile Nanofibres for the Photodegradation of Methyl Orange." International Journal of Photoenergy, vol. 2016, 2016, pp. 1-9, doi:10.1155/2016/3162976.Link [11] Ding, Bin, et al. Electrospun Nanofibers for Energy and Environmental Applications. Springer Berlin Heidelberg, Berlin, Heidelberg, 2014, doi:10.1007/978-3-642-54160-5. ch. 6, pp. 142. ch. 7, sec. 7.1, pp. 163,–165.Link [12] Bagot͡ skiĭ, V. S., et al. Electrochemical Power Sources: Batteries, Fuel Cells, and Supercapacitors. John Wiley & Sons, Inc, Hoboken, New Jersey, 2015. ch. 1, sec. 1.5. ch. 13.Link [13] Calvo-Flores, Francisco G., et al. Lignin and Lignans as Renewable Raw Materials: Chemistry, Technology and Applications. John Wiley and Sons, Inc, Chichester, West Sussex, 2015. ch. 1, sec. 1.2, pp. 5. ch. 2, sec. 2.1, pp. 11. [14] “2132 and 2116 PID Temperature Controllers,” Aug 07.  


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