Electrolyte with New Composition for High Nickel Lithium Ion Batteries

We previously reported 1-4 the in situ electrolyte additives to selectively synthesize the beneficial lithium tetrafluorophosphate components in high yield (> 98%) and maximize the battery performance. The in situ method is particularly of interest to scale up electrolyte preparation since it would alleviate any requirements of extra separation and purification of the desired additives. Here we used a new strategy of change both the composition and materials in the standard electrolyte to formulate advanced electrolytes for lithium ion batteries (LIBs). New electrolytes for high voltage LIBs were demonstrated to be more effective than the previous additives. The LIBs containing Ni-rich cathodes cycled with the new electrolytes in optimal composition rendered better electrochemical performance than cells cycled with the start-of-art Gen2 electrolyte when cycled between 3.0 to 4.2 V, exhibiting effective suppression of the impedance rise during aging. 1 H Nuclear Magnetic Resonance spectra of cycled new electrolyte suggested their capabilities in preventing the transesterification reactions on anode surface, while X-ray photoelectron spectroscopy and inductively coupled plasma mass spectrometry analysis indicated its ability to form a stable cathode interface and mitigate structural damage on the cathode surface. Further analysis also indicated the benefits of the new composition electrolyte in protecting the cathode bulk structure. [1] 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. [2] C. Liao, eTransportation , 2020, 5 , 100068. [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.