A multi-faceted approach towards improving the performance of silicon electrodes for next-generation lithium-ion batteries
Open Access
- Author:
- Melnyk, Michael Joseph
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 24, 2015
- Committee Members:
- Donghai Wang, Thesis Advisor/Co-Advisor
- Keywords:
- battery
lithium-ion
silicon anode
secondary storage
electrochemical energy - Abstract:
- Although lithium-ion battery technology has been the catalyst in enabling modern electric vehicle, mobile device, and large-scale energy storage technology, the increasing power demands by end-users has motivated research in developing the next-generation of lithium-ion batteries. This next generation of batteries will need to achieve higher energy and power densities, while remaining chemically stable. Silicon-based active material has been proposed as a solution in achieving superior battery performance, as it can offer a lithium storage capacity (4200 mAh/g) tenfold higher than the carbonaceous electrodes employed in commercial Li-ion cells, while also offering superior safety characteristics. Unfortunately, the higher lithium storage capacity translates into an immense volume expansion (300 - 400%) upon lithiation, and thus the mechanical integrity and electrochemical performance of the electrodes are very unstable. Within the past decade, the performance of Si-based electrodes has been greatly improved as active material morphologies, polymer binders, electrolyte additives, and theoretical models have provided solutions in alleviating the stresses and strains generated during Si lithiation/delithiation. A multi-faceted solution pathway is enacted in this research to develop a Si-based electrode that can achieve cycling performance relevant to industrial application, while also offering insight on the influence of several aspects of the Si-based electrode design on cycling performance. From this investigation, a Si-based electrode has been developed with carbon-coated silicon monoxide active material and polyacrylic acid polymer binder, both of which offer several complimentary attributes that enable a moderately stable cycling performance at high active mass loading while offering a gravimetric and areal lithium capacity magnitude relevant to industrial applications. Although much work lies ahead in further improving the capacity retention of the Si-based electrodes reported in this thesis, this work presents an economical platform for future work on the topic.