Improving the cycleability of Si anodes by covalently grafting with 4-carboxyphenyl groups

In this study, the lithium storage capacity of Si nanoparticles is significantly enhanced by grafting with 4-carboxyphenyl groups via diazonium salts. The modified Si anodes exhibit reversible capacities of 1173 and 527 mA h g−1 at the 1st and 50th cycle, while those of the bare Si electrodes are only 56 and 62 mA h g−1, respectively. The improved electrochemical performance is supposed to arise from the formation of a robust and flexible solid electrolyte interface on the surfaces of the modified Si nanoparticles.