Electrolytes for High Nickel Lithium-Ion Batteries

We have shown different strategies 1, 2 in improving capacity retention and reducing impedance rise in modifying additives: in situ electrolyte additives to synthesize the beneficial lithium tetrafluorophosphate components 3, 4 or dual-salt electrolytes 1 for reducing cathodic impedance. The cathodes we have tested have a LiNiO 2 structure with an ultra-low amount of Co/Mn. An improved structural stability compared to that of LiNiO 2 can be achieved while maintaining the high Ni content and high specific capacity. Using an optimal ratio of Ni/Mn/Co of 90/5/5 for a LiNi 90 Mn 5 Co 5 O 2 cathodes, 5 we here report the reduced reactivity of electrolytes using a combinatorial approach of reducing EC and introducing effective additives, targeting both a more robust SEI formation and a less resistive cathode electrolyte interface. Multifaceted posttest analytical methods were used to understand the failure mechanism of the baseline cells and how additives/solvents approaches help the performance. For example, the new electrolytes prevent the transesterification reactions on anode surface, form a stable cathode interface, and mitigate structural damage on the cathode surface. Further analysis also investigated the how electrolytes protect the cathode bulk structure. [1] J. Yang, M.-T. Fonseca Rodrigues, S.-B. Son, J. C. Garcia, K. Liu, J. Gim, H. Iddir, D. P. Abraham, Z. Zhang and C. Liao, ACS Applied Materials & Interfaces , 2021. [2] J. Yang, I. Shkrob, K. Liu, J. Connell, N. L. Dietz Rago, Z. Zhang and C. Liao, Journal of The Electrochemical Society , 2020, 167 , 070533. [3] J. Yang, I. Shkrob, Q. Liu, N. L. Dietz Rago, Y. Liu, K. Liu, Z. Zhang and C. Liao, Journal of Power Sources , 2019, 438 , 227039. [4] I. A. Shkrob, B. Han, R. Sahore, A. P. Tornheim, L. Zhang, D. P. Abraham, F. Dogan, Z. Zhang and C. Liao, Chemistry of Materials , 2019, 31 , 2459-2468. [5] C. S. Yoon, M. H. Choi, B.-B. Lim, E.-J. Lee and Y.-K. Sun, Journal of The Electrochemical Society , 2015, 162 , A2483-A2489.