DEVELOPMENT OF ADVANCED ANODE MATERIALS AND SOLID-STATE ELECTROLYTES FOR SODIUM-ION BATTERY
Open Access
- Author:
- Yu, Zhaoxin
- Graduate Program:
- Mechanical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- July 14, 2017
- Committee Members:
- Donghai Wang, Dissertation Advisor/Co-Advisor
Donghai Wang, Committee Chair/Co-Chair
Adrianus C Van Duin, Committee Member
Zi-Kui Liu, Committee Member
Thomas E Mallouk, Outside Member
Sulin Zhang, Outside Member - Keywords:
- Sodium ion battery
red phosphorus
solid state electrolyte
solid state battery
anode - Abstract:
- Na-ion batteries (NIBs) are promising candidates for widely used Li-ion batteries (LIBs) and have attracted increasing attention due to the abundance of sodium sources, the even global distribution of such sources, and NIBs’ similar intercalation chemistry to LIBs. However, the current existing anode materials are still not satisfying for the practical application due to their low specific capacity or limited cycling life. Therefore, Chapter 3 and 4 focuses on development of phosphorus-based anode material for NIBs. In Chapter 3, phosphorus-graphene nanosheet (P/G) hybrid is synthesized by ball-mill method and show extremely high specific discharge capacity of 2077 mAhg-1 for the initial cycle as well as capacity retention of 95% relative to the second cycle after 60 cycles. Taking the facile and general method as well as the low cost starting materials into account, this promising P/G hybrid nanostructured anode has a great potential for practical application in high performance NIB. In Chapter 4, two phosphorus-carbon composites, P@carbon nanotube (P@CNT) and P@porous carbon, are developed. Nano-sized phosphorus particles have been deposited on the surface of two carbon hosts through well-controlled vaporization-deposition-conversion method. By confining P inside micropores of carbon host, P@porous carbon composite exhibits a high initial specific capacity of 1705 mAhg-1p (~ 852 mAhg-1composite) and superior capacity retention of 92% after 100 cycles and 46% after 1000 cycles, which is much better than that for P@CNT composite. All the above mentioned work have been done by using organic liquid electrolyte. It is well known that severe safety issues exist in NIBs because of extremely high reactivity of sodium metal in volatile and flammable organic liquid electrolyte. Solid-state NIB with solid-state electrolyte (SSE) is attractive because it can potentially address the safety issues and also achieve long cycle life. Therefore, Chapter 5 and 6 focus on development of sulfide-based solid-state electrolyte for NIBs. In Chapter 5, a new Na-ion SSE, Na3P0.62As0.38S4, has been discovered with an exceptionally high conductivity of 1.46 mS cm-1 at room temperature, enhanced moisture stability, superior electrochemical stability and performance. In Chapter 6, a new Na-ion superior conductor, Na11Sn1.94PS12, with a unique structure different from that for any reported solid-state electrolyte has been developed and exhibits a superior grain conductivity of 3.0 mS cm-1 and total ionic conductivity of 1.06 mS cm-1 at 25 °C.