Reverse microemulsion-assisted in situ SiO₂ interfacial engineering for enhanced stability of NCM523 cathodes

Interfacial instability and structural degradation remain critical challenges for layered oxide cathodes in lithium-ion batteries. Herein, a reverse microemulsion-assisted strategy is reported to achieve in situ SiO₂ interfacial engineering of NCM523 cathodes during precursor synthesis. The introduction of an amphiphilic silane coupling agent enables synergistic regulation of particle growth and formation of a conformal amorphous SiO₂ coating after calcination. By optimizing the SiO₂ content, the NCM-3%Si cathode exhibits reduced polarization, suppressed interfacial side reactions, and improved structural integrity during electrochemical cycling. As a result, enhanced cycling stability and rate performance are achieved compared with the uncoated counterpart. This work demonstrates that microemulsion-assisted in situ coating provides an effective route for interfacial stabilization of layered oxide cathodes and offers practical insights for improving the durability of lithium-ion battery materials.