H-Transfer Mediated Self-Enhanced Interphase for High-Voltage Lithium-Ion Batteries

Abstract

The dehydrogenation of solvents presents a significant challenge at the cathode–electrolyte interface (CEI) in high-voltage lithium-ion batteries (LIBs), resulting in the generation of corrosive HF and posing detrimental effects on the sustainability of LIBs. Herein, we propose an interfacial self-enhanced strategy mediated by H-transfer to mitigate solvent dehydrogenation at the CEI. As a proof of concept, trimethyl phosphate (TMP) was coupled with 1,1,2,2,3,3,4-heptafluorocyclopentane (HFCP) to prepare the high-voltage electrolyte, where TMP serves to capture H free radicals produced by the dehydrogenation of HFCP, while the dehydrogenated-HFCP radicals would in situ passivate the cathode/electrolyte interface. The TMP/HFCP electrolyte enables a 4.4 V graphite||LiNi_0.8Co_0.1Mn_0.1O₂ LIB to achieve over 90% capacity retention after 1300 cycles at 0.5 C. Furthermore, the TMP/HFCP electrolyte exhibits favorable properties in terms of nonflammability and minimal gas production during electrochemical and thermal tests. This work presents a promising pathway for realizing high-voltage and high-safety LIBs.