Rational Design of a Piezoelectric BaTiO3 Nanodot Surface‐Modified LiNi0.6Co0.2Mn0.2O2 Cathode Material for High‐Rate Lithium‐Ion Batteries

Abstract Nickel‐rich cathode materials have been regarded as the most promising candidates for lithium‐ion batteries because of their superior specific capacity and cost‐effectiveness. However, the rapid capacity fade under high current density and serious side reactions during long‐term cycling hinder its wide application. In this study, piezoelectric BaTiO 3 nanodots are employed as a functional coating layer on the LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode material to balance the relationship between structure and performance. A three‐phase interface model is proposed including the LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode material, uniform piezoelectric BaTiO 3 nanodots, and the electrolyte. The coating layer plays a key role in the rapid diffusion of lithium‐ions as well as stabilizing the bulk structure of the cathode materials. Furthermore, the possible by‐products generated during the electrochemical cycling that can be alleviated by the modification of BaTiO 3 are detected by using differential electrochemical mass spectrometry. As expected, our strategy efficiently improves the structural stability and holds a high‐rate performance.