Effective collaborative strategy enabling stable interphase and crystal structure for high-performance Ni-rich single-crystal LiNi0.83Co0.11Mn0.06O2 cathode

Abstract

To address the structural and interfacial degradation of Ni-rich layered cathodes, a collaborative strategy combining Ti⁴⁺ ions doping with in situ-formed Li₃PO₄ coating is designed to regulate and optimize Ni-rich single-crystal LiNi_0.83Co_0.11Mn_0.06O₂ (SC-NCM-TP) cathode. The introduced Ti⁴⁺ ions not only strengthen the crystal framework and inhibit harmful phase transition by forming stronger Ti-O bonds, but also boost Li⁺ ions kinetics by expanding migration channels. Moreover, a uniform Li₃PO₄ conductive coating with a thickness of about 3 nm, generated by converting surface residual lithium salts through NH₄H₂PO₄ treatment, enhances cathode/electrolyte interfacial stability. Benefiting from these advantages, the SC-NCM-TP based cell demonstrates exceptional capacity retention ratio of 90.3 % at 25 °C and 84.6 % at 60 °C after 100 cycles under 1.0 C, and maintains excellent capacity retention ratio of 81.3 % after 200 cycles even at 5.0 C. Hence, this work sheds new light on the design of advanced single-crystal cathodes for lithium-ion batteries.