Artificial Interface Derived from Diphenyl Ether Additive for High‐Voltage LiNi0.5Mn1.5O4 Cathode

Abstract Diphenyl ether (DPE) is investigated as a film‐forming additive to improve the cyclic stability of LiNi 0.5 Mn 1.5 O 4 at high voltage and elevated temperature (55 °C). Addition of DPE in the baseline electrolyte significantly improves the capacity retention of LiNi 0.5 Mn 1.5 O 4 at elevated temperature. Its capacity retention increases from 41.2 % at the baseline electrolyte to 90.5 % after 0.1 vol% DPE is added to the baseline electrolyte in 100 cycles. Calculations demonstrate that DPE is oxidized preferentially to the baseline electrolyte. The experimental results show that a robust and uniform film is generated on the LiNi 0.5 Mn 1.5 O 4 surface, alleviating the subsequent electrolyte decomposition and protecting LiNi 0.5 Mn 1.5 O 4 from transition metal dissolution and structural destruction.