A New Strategy to Stabilize Capacity and Insight into the Interface Behavior in Electrochemical Reaction of LiNi_0.5Mn_1.5O₄/Graphite System for High-Voltage Lithium-Ion Batteries

The performance of CEI and SEI configuration and formation mechanism on the cathode and anode side for LiNi 0.5 Mn 1.5 O 4 /natural graphite (LNMO/NG) batteries is investigated, where series permutations of the NG electrodes modified with TEOS species as the anode for the LNMO full cells. It is believed that the excellent long-term cycling performance of LNMO/NG full cells at the high voltage is a result of alleviating the devastated reaction to form the CEI and SEI on the both electrodes with electrolyte, respectively. At a voltage range from 3.4 to 4.8 V for the LNMO full cells, 95.0% capacity retention after 100 cycles is achieved when cycled with TEOS-modifying NG anode. This mechanism may be explained that eliminating the HF and absorbing water impurities in the electrolyte by introducing the TEOS group, which can transform the SiO 2 species that react with the acid of HF at the organic solvent environment instead of destroying/forming the anode SEI and attacking the LNMO spinel structure to form the dense and high resistance CEI, meanwhile the SiO 2 species will absorb the water molecule and precipitate into the anode surface further stabilizing the SEI configuration during the cycling.