Controllable construction of non-hydrophilic Cu-PmPD nanoshells on Ni-rich cathode materials in non-aqueous system for lithium-ion batteries

Due to high specific capacity and relatively low price, Ni-rich layered transition-metal oxides have been regarded as the promising cathode materials for next-generation lithium-ion batteries (LIBs), but the poor cycling stability and residual lithium hinder its widely application. Herein, by controlling the growth ki-netics of Cu2+- poly (m-phenylenediamine) (Cu-PmPD) in the mixed organic solvent, the non-hydrophilic Cu-PmPD nanoshells with controllable thickness (5 nm, 10 nm, 20 nm) were successfully coated on LiNi0.6Co0.2Mn0.2O2 (622) materials for the first time. As a consequence, Cu-PmPD nanoshells could effec-tively hinder the transition metal (Ni, Co, Mn) dissolution during the charge/discharge cycles. Benefiting from the non-hydrophilic Cu-PmPD nanoshells, 622 @Cu-PmPD as cathode materials for LIBs exhibit the greatly improved electrochemical performance than pristine LiNi0.6Co0.2Mn0.2O2 matrix, among 5 nm na-noshells were testified to be the optimized protective shells. Furthermore, the non-hydrophilic Cu-PmPD could hinder the formation of residual lithium through preventing the contact between H2O and LiNi0.6Co0.2Mn0.2O2, and thus the 622 @Cu-PmPD still possess excellent electrochemical properties even after storing in humid air for 2 months. The work opens a new avenue for modifying Ni-rich cathode materials in the non-aqueous system.(c) 2023 Elsevier B.V. All rights reserved.