Improved adhesion of cross-linked binder and SiO2-coating enhances structural and cyclic stability of silicon electrodes for lithium-ion batteries

Silicon (Si) has been considered as a promising alternative anode material for high energy density lithium-ion batteries because of high theoretical capacity, low cost, environmentally benign, and abundant source. But the huge volume change during cycles greatly hinders the application of Si anodes. Constructing robust electrode structures via effective binders are still a challenge. Herein, a cross-linked polyacrylic acid and glycerol (PAA-GL) binder is synthesized in situ and a surface coating of silicon dioxide is obtained on silicon nanoparticles (Si@SiO2), both of which together construct a strong electrode. The Cross-linked binder with massive hydroxyl and carboxyl groups possesses luxuriant contact sites to Si@SiO2, meanwhile, the free carboxyl groups of binder and hydroxyl of Si@SiO2 offer an enhanced interaction, leading to robust electrode with strong mechanical properties. Except for binder, the SiO2-modified coat acts as a protective layer to buffer volume change of Si. Therefore, the remarkable structural stability is obtained. In addition, the Si@SiO2-PAA-GL electrode exhibits excellent electrochemical performance, a high capacity of 1192.7 mA h g(-1) at 2 C after 500 cycles with a teeny capacity decay rate of 0.0337% per cycle.