A dual functional wrapping layer for enhanced cyclic performance of high-loading silicon anodes

•A facile and efficient surface modification technique on Si electrode is developed.•Optimized coating layer greatly contributes to cycling stability of Si anode.•Highly enhanced capacity retention of 81% over 100 cycles is achieved.•A possible mechanism for performance improvement is proposed.

This work presents an efficient surface coating layer, a polyacrylic acid (PAA) layer doped with silica nanoparticles, providing highly enhanced cyclic stability of silicon anodes, without any loss in rate capability. Electrochemical characterizations show that the modified electrode retains 81% of the original capacity after 100 cycles, compared with 47% for the pristine electrode. The improved cyclic stability is ascribed to the porous and robust surface coating layer that makes the active material in intimate contact with both current collector and conductive additive while inhibits continuous parasitic reaction between silicon and electrolyte. In addition, the porosity of this coating layer provides the diffusion pathway for Li+ and thus ensures good rate capability.

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