Graphene oxide-immobilized NH₂-terminated silicon nanoparticles by cross-linked interactions for highly stable silicon negative electrodes

There is a great interest in the utilization of silicon-based anodes for lithium-ion batteries. However, its poor cycling stability, which is caused by a dramatic volume change during lithium-ion intercalation, and intrinsic low electric conductivity hamper its industrial applications. A facile strategy is reported here to fabricate graphene oxide-immobilized NH₂-terminated silicon nanoparticles (NPs) negative electrode (Si@NH₂/GO) directed by hydrogen bonding and cross-linked interactions to enhance the capacity retention of the anode. The NH₂-modified Si NPs first form strong hydrogen bonds and covalent bonds with GO. The Si@NH₂/GO composite further forms hydrogen bonds and covalent bonds with sodium alginate, which acts as a binder, to yield a stable composite negative electrode. These two chemical cross-linked/hydrogen bonding interactions - one between NH₂- modified Si NPs and GO, and another between the GO and sodium alginate - along with highly mechanically flexible graphene oxide, produced a robust network in the negative electrode system to stabilize the electrode during discharge and charge cycles. The as-prepared Si@NH₂/GO electrode exhibits an outstanding capacity retention capability and good rate performance, delivering a reversible capacity of 1000 mAh g^-1 after 400 cycles at a current of 420 mA g^-1 with almost 100% capacity retention. The results indicated the importance of system-level strategy for fabricating stable electrodes with improved electrochemical performance. © 2014 American Chemical Society.