Island-like coating with Pr₆O₁₁ nanoparticles enables high-voltage and durable LiNi_0.5Mn_1.5O₄ cathode

Spinel LiNi_0.5Mn_1.5O₄ (LNMO) is a promising high-voltage cathode material for next generation lithium-ion batteries. However, its application is limited by severe interfacial side reactions and structural degradation under high-voltage conditions, which lead to poor cycling stability and inferior rate performance. Conventional full-coverage coatings cannot withstand cyclic mechanical stress during charge-discharge processes, easily causing cracks and performance fading. In this work, an island-like coating structure based on Pr₆O₁₁ nanoparticles was immobilized on the LNMO surface (Pr₆O₁₁-LNMO). The island-like structure can adapt to volume changes during cycling, inhibit the dissolution of transition metals and slow down electrolyte decomposition. The oxygen vacancies in Pr₆O₁₁ enable fast Li⁺ transport, and the Pr⁴⁺/Pr³⁺ valence equilibrium of Pr₆O₁₁ can increase the Mn⁴⁺ content in LNMO, thereby alleviating the Jahn-Teller distortion induced by Mn³⁺. In-situ XRD results reveal that faster Li⁺ kinetics and better interfacial stability inhibit the two-phase transition of LNMO and orient it toward a reversible solid-solution reaction. The optimized Pr₆O₁₁-LNMO exhibits superior cycling stability (94.6% capacity retention after 500 cycles at 1C) and excellent rate capability (111.9 mAh g⁻¹ at 20C). This strategy provides a promising solution for preparing durable high-voltage LNMO cathodes and facilitates the advancement of lithium-ion batteries with high energy density.