Thursday, 2 June 2022: 08:00
West Meeting Room 109 (Vancouver Convention Center)
Conventional graphite may not be the best choice as the negative electrode against LiNiMnCoO2 (NMC, 1:1:1 or 5:2:2 or 6:2:2) positive electrode of fast chargeable high-power Li-ion cells in view of lithium plating and possible thermal runaway. Li4Ti5O12 (LTO) has replaced graphite anode of the Li-ion cells assuring high safety and long cycle life for high power applications especially in all marine sectors for safety reasons [1]. Though phosphate-based cathodes are proven to be far safer than oxide-based cathodes, 18650-sized cells of LiNi0.33Mn0.33 Co0.33O2 vs Li4Ti5O12 show higher energy density, 65Wh/kg than LiFePO4 vs Li4Ti5O12 cells with 50Wh/kg. Comparatively LiFePO4 vs graphite cells have 105Wh/kg. As a result, LTO technology is more expensive than graphite technology (~ $500-600/kWh vs $100-150/kWh).
In this talk, we present our recent work towards developing high-power Li-ion cells with higher energy density and lower cost than LTO technologies.
- Heat generation and internal resistance of LiNi33Mn0.33 Co0.33O2 vs Li4Ti5O12 high-power cell using two component and three component electrolytes are compared. It is shown that the SEI formation in these LTO cells is quite sensitive to the electrolyte composition.
- Replacing NMC using LiMnFePO4 helps in improving the safety features especially at high voltage and high temperature [2]. Full cell data on LiMnFePO4 vs Li4Ti5O12 safe Li-ion cell will be shared (Fig 1).
- Mesoporous TiO2 negative electrode [3] is proposed as an alternate to Li4Ti5O12.
- High rate performance of 18650-sized cells using mesoporous TiO2 negative electrode will be presented.
Our preliminary results show that LiMnFePO4 vs mesoporous TiO2 technology can address safety as well as cost aspects of the proposed high-power Li-ion cells.
References:
[1] EMSA Maritime Battery Study: Electrical Energy Storage for Ships, DNV GL – Report No. 2019-0217, Rev. 04, 2020.
[2] V. Ramar and P. Balaya, Physical Chemistry Chemical Physics, 2013, 15, pp 17240-17249.
[3] K. Saravanan, K. Ananthanarayan, and P. Balaya, Energy & Environmental Science, 2010, 3, pp 939 – 948.