Porous Structuring of Si Microparticles for Li-Ion Battery Anodes by Urea-Assisted Etching

after 100 cycles at 0.1 C, with Coulombic efficiencies of 98.8-99.7%, whereas higher silicon loadings lead to rapid capacity decay. Cycling-resolved impedance and differential-capacity analyses reveal the formation of a thicker yet mechanically resilient interphase that stabilizes charge-transfer kinetics, while rate capability tests show 65-74% capacity retention at 2 C.