Construction of LiNi_0.5Mn_1.5O₄ Spinel Layer-Bearing Heterostructural Li-Rich Layered Oxide Cathodes with Enhanced Structural Integrity and Cycling Stability

Li-rich layered oxides (LLOs) are promising candidates for the cathode materials of next-generation high-energy density lithium-ion batteries because of their high reversible capacity and operating voltages. However, the LLOs always undergo structure transformation, which can result in rapid decay of capacity and voltage. Herein, LiNi0.5Mn1.5O4 (LNMO) spinel layers are constructed on the surfaces of Li1.2Mn0.54Ni0.13Co0.13O2 (LLO) particles synthesized by a coprecipitation method to form a heterostructural LLO-LNMO cathode. The LLO-LNMO cathode with 1% LNMO displays a more stable long-cycling life with 82.3% capacity retention and 0.534 V voltage drop after 400 cycles at 1 C. A capacity retention of 79.6% with a voltage decay of 0.545 V after 1000 cycles at 5 C is also achieved. A calculation based on density functional theory (DFT) also indicates that lattice oxygen can be stabilized by the LNMO spinel layer. This work demonstrates that the construction of a heterostructural LLO-LNMO cathode with an LNMO spinel layer covering the surfaces of LLO can inhibit the degradation of the layered structure of LLO, restrain the voltage attenuation, and achieve enhanced long-cycling properties for potential applications of high-performance lithium-ion batteries.