A New Strategy to Stabilize Capacity and Insight into the Interface Behavior in Electrochemical Reaction of LiNi0.5Mn1.5O4/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 LiNi0.5Mn1.5O4/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 SiO2 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 SiO2 species will absorb the water molecule and precipitate into the anode surface further stabilizing the SEI configuration during the cycling.