Primary Particle Thickness of Mn-Based Hydroxide Precursors: Impact on Li-Rich Mn-Based Cathode Structure and Electrochemical Performance

Li-rich manganese-based layered oxides (LMR) are pivotal for next-generation high-energy-density lithium-ion batteries due to their capacity exceeding 250 mAh/g. Although previous studies have investigated morphology control and performance comparisons between carbonate and hydroxide precursors for ternary cathode materials, research on the critical structural parameter of primary particle thickness in hydroxide precursors remains fragmented and lacks systematic summarization. Consequently, a clear structure–property relationship linking this parameter to the electrochemical performance of the final cathode material has yet to be established. Research indicates that reducing the thickness of the precursor primary particles enhances the uniformity of lithiation during sintering. Simultaneously, cathode materials synthesized from thinner precursor primary particles typically exhibit higher porosity, which can effectively mitigate stress accumulation during charge–discharge cycles and significantly improve the lithium-ion migration efficiency. The final study showed that the sheet thickness was reduced from 190 to 98 nm, the first-cycle discharge capacity was increased to 266.63 mAh·g–1, and the discharge capacity retention at 5C relative to 0.1C was increased by 46% (from 42.4 to 61.9%). It establishes primary particle thickness as a key descriptor for precursor design, enabling targeted optimization of ion-transport kinetics. This work establishes a microcrystalline engineering strategy that reconciles the rate–stability trade-off in Mn-based cathodes, advancing the commercialization of LMR for emerging applications requiring high energy density and longevity.