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

• Published in: Journal of alloys and compounds 2023-05, Vol.944, p.169264, Article 169264
• Main Authors: Tao, Xian-Sen, Wang, Tong, Wang, Yunliang, Song, Xue-Jing, Li, Xin-Run, Sha, Jingquan
• Format: Article
• Language: English
• Subjects: Cu2+- poly (m-phenylenediamine); Cycling stability; Lithium-ion batteries; Ni-rich cathode materials; Residual lithium
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2023.169264

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 kinetics 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 effectively 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 nanoshells 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. •Non-hydrophilic Cu2+-poly(m-phenylenediamine) (Cu-PmPD) nanoshells form on LiNi0.6Co0.2Mn0.2O2 in non-aqueous system.•Cu-PmPD nanoshells could protect the LiNi0.6Co0.2Mn0.2O2, and suppress the formation of residual lithium.•Uniform Cu-PmPD nanoshells with adjustable thickness are achieved through controlling the growth kinetics.