Synergetic modulation of LATP coating and Se doping enables enhanced rate capability of layered Li-rich oxide

Abstract

Lithium-rich manganese-based cathode materials (LRMO) have emerged as the predominant cathode materials for next-generation lithium-ion batteries (LIBs) due to their advantages of high energy density. At elevated voltages (≥4.5 V), the partly reversible oxidation and reduction reactions of oxygen anions within LRMO give rise to the degradation of lattice oxygen, facilitating the migration of transition metal (TM) ions towards the lithium sites. Ultimately, the disintegration of the lamellar structure for LRMO leads to substantial voltage decay and reduced initial coulombic efficiency (ICE). In this work, a novel dual modification strategy of solid electrolyte coating layer construction of Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) and Se doping for Li_1.2Mn_0.52Ni_0.2Co_0.08O₂ (LRMO) have been adopted to enhance the structure stability and improve the lithium diffusion kinetics. Coating LRMO with LATP can effectively suppress the migration of TM ions to the lithium layer, while Se substitute for oxygen vacancies in LRMO, thereby inhibiting lattice oxygen loss and achieving excellent performance. The obtained sample exhibits a notably enhanced capacity retention of 75.1% from 61.9% after 300 cycles at 1C compared to the bare LRMO. This strategy, which stabilizes the layered structure of the material from two different perspectives, extends the research approach for LIBs.