Theoretical insights on alleviating lattice-oxygen evolution by sulfur substitution in Li_(1.2)Ni_(0.6)Mn_(0.2)O_(2) cathode material

Here,we demonstrate that the lattice oxygen release on the high-capacity cathode,Li_(1.2)Ni_(0.6)Mn_(0.2)O_(2)(LNMO)surface can be successfully suppressed through S-anion-substitution using density functional theory(DFT)calculations and ab initio molecular dynamics(AIMD)simulations.The oxygen evolution mechanisms on pristine and sulfur(S)-substituted LNMO(003)surfaces in the presence of an electrolyte mixture are compared.Over-oxidation of O^(2−)anions during delithiation in the pristine surface results in oxygen evolution and subsequent structural deformation.Whereas,in the S-substituted LNMO,S^(2−)anions primarily participate in charge compensation and further inhibit oxygen evolution and O vacancy formation at high degrees of delithiation.Furthermore,the S-substitution effectively prevents the formation of Ni^(3+)ions and Jahn-Teller distortion,retaining the layered structure during delithiation.Our findings provide insight into improving the structural stability of the LNMO(003)surface,paving the way for developing Li-rich LNMO cathode materials for next-generation LIBs.