(Georgia Institute of Technology, 2021-12-14)
Yushin, Gleb
During the last 30 years the evolutionary improvements in lithium-ion battery (LIB) technologies increased LIB volumetric and gravimetric energy densities by over 3 times and reduced cell price by up to 50 times. As a result, LIBs mostly replaced other rechargeable battery technologies for most portable applications. To accelerate the transition to renewable energy economy and electric transportation the cost of LIBs should be reduced rapidly and drastically, from the current $100-200 kWh-1 to below $50 kWh-1. This can become feasible if traditional intercalation-type active electrode materials in LIB construction are replaced with low-cost, broadly available, high-capacity conversion-type active materials. Unfortunately, conversion active materials suffer from multiple limitations, such as large volume changes, low conductivity, and unfavorable interactions with liquid electrolytes, commonly leading to low attainable energy density, significant impedance growth, rapid capacity decay and premature cell failure. In my invited talk I will discuss the key materials’ challenges and provide examples to overcome these. For industrial applications, synthesis methods need to additionally be inexpensive at scale and rely on the use of low-cost, broadly available precursors. Finally, it is important that novel materials remain fully compatible with currently operating and planned LIB factories to enable their successful commercialization.
(Georgia Institute of Technology, 2020-01)
Sun, Zifei; Lu, Peilin; Fu, Wenbin; Wang, Baichuan; Magasinski, Alexandre; Zhang, Yawei; Yushin, Gleb
Iron fluoride (FeF3) is considered as a potential cathode for sodium-ion batteries due to its high capacity and low cost. However, the dissolution of active materials during cycling limits its further development. Herein, we design thin protective films at the surface of cathode materials by in-situ and ex-situ method. In in-situ method, an electrolyte of sodium-difluoro(oxalate)borate (NaDFOB) dissolved in a ternary solvent was utilized to develop the in-situ protective films. Ex-situ formed coatings are developed by atomic layer deposition technique. Both coatings minimize the active material dissolution and significantly improved the overall electrochemical performance of FeF3 cathodes in SIBs.