Lignin-derived hard carbon anode for potassium-ion batteries : interplay among lignin molecular weight, material structures, electrolyte chemistry, and storage mechanisms
department or school: Applied Science, Faculty of
department or school: Engineering, School of (Okanagan)
data provider: DSpace
degree campus: UBCO
creator: Wu, Zhenrui
issued: 2021-07-12T22:01:18Z
issued: 2021
related degree: Master of Applied Science - MASc
degree grantor: University of British Columbia
description: Potassium-ion battery (PIB) is a rising star in the rechargeable battery field due to its potential low cost and high energy for large-scale applications. Hard carbon (HC) is one of the most popular anodes for practical PIBs due to its high K-ion storage and relatively low material cost. Primarily, biomass (such as lignin) represents an abundant source for synthesizing HC. This thesis developed a series of HCs from lignin with different molecular weights (MWs) at serial pyrolysis temperatures (PTs) of 500–1000 °C, exhibiting varying electrochemical performance. The best lignin-derived HC (LHC) was pyrolyzed from medium-MW lignin at 700 °C (M700) and delivered a high reversible specific capacity of ~300 mAh g⁻¹ at 50 mA g⁻¹. M700 exhibited an optimal mixture of graphite-like nanocrystals with the most significant interlayer distance and amorphous structure to maximize K-ion storage from bulk insertion and surface adsorption. The role of electrolytes was then investigated to determine the LHC performance and K-ion storage mechanism. We systematically studied the influence of four electrolyte systems, i.e., two K salts (KPF⁶ and KFSI) in carbonate ester and ether solvents, on ionic mobility, cycling stability, and charge transfer kinetics of M700 in PIBs. It is found that the M700 anode achieved the best cycling stability and kinetics performance in the KFSI EC/DEC electrolyte. Mechanimsic study disclosed that the improved performance could be ascribed to the formation of robust KF-rich SEI resulting from FSI⁻ decomposition, which effectively prevented irreversible side reactions and severe structural decay (e.g., exfoliation and pulverization). The degradation mechanisms of other electrolyte systems are also explained by SEI formation and solvation/desolvation effect. It is expected that this work will provide guidance on the anode and electrolyte selection and design for PIBs in the near future.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/78925
note: LIGNIN-DERIVED HARD CARBON ANODE FOR POTASSIUM-ION BATTERIES: INTERPLAY AMONG LIGNIN MOLECULAR WEIGHT, MATERIAL STRUCTURES, ELECTROLYTE CHEMISTRY, AND STORAGE MECHANISMS by Zhenrui Wu B.Sc., University of Electronic Science and Technology of China, 2019 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE COLLEGE OF GRADUATE STUDIES (Mechanical Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Okanagan) June 2021 © Zhenrui, 2021 ii The following individuals certify that they have read, and recommend to the College of Graduate Studies for acceptance, a thesis/dissertation entitled: LIGNIN-DERIVED HARD CARBON ANODE FOR POTASSIUM-ION BATTERIES: INTERPLAY AMONG LIGNIN MOLECULAR WEIGHT, MATERIAL STRUCTURES, ELECTROLYTE CHEMISTRY, AND STORAGE MECHANISMS submitted by Zhenrui Wu in partial fulfillment of the requirements of the degree of Master of Applied Science . Dr. Jian Liu, School of Engineering Supervisor Dr. Dimitry Sediako, School of Engineering Supervisory Committee Member Dr. Mohammad Arjmand, School of Engineering Supervisory Committee Member Dr. Sumi Siddiqua University Examiner iii Abstract Potassium-ion battery (PIB) is a rising star in the rechargeable battery field due to its potential low cost and high energy for large-scale applications. Hard carbon (HC) is one of the most popular anodes for practical PIBs due to its high K-ion storage and relatively low material cost. Primarily, biomass (such as lignin) represents an abundant source for synthesizing HC. This thesis developed a series of HCs from lignin with different molecular weights (MWs) at serial pyrolysis temperatures (PTs) of 500–1000 °C, exhibiting varying electrochemical performance. The best lignin-derived HC (LHC) was pyrolyzed from medium-MW lignin at 700 °C (M700) and delivered a high reversible specific capacity of ~300 mAh g-1 at 50 mA g-1. M700 exhibited an optimal mixture of graphite-like nanocrystals with the most significant interlayer d…
has type: Thesis/Dissertation
date issued: 2021-09
is shown at: 10.14288/1.0400127
language: eng
degree discipline: Mechanical Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Liu, Jian
type: Text
identifier URI: http://hdl.handle.net/2429/78925