Building sponge-like robust architectures of CNT-graphene-Si composites with enhanced rate and cycling performance for lithium-ion batteries

A three-dimensional robust architecture of a Si-based electrode material is designed and fabricated by shielding Si nanoparticles with intertwined CNTs and graphene. Such a sponge-like unique structure bestows long cycling stability of the electrode by providing void space and efficient confinement for the volume change of Si. In addition, the intimate contact between Si and highly conductive carbon networks improves the electrode kinetics. As a result, such a composite exhibits an outstanding capacity of 1337 mA h g^-1 after 100 cycles at a current density of 1.0 A g^-1, and an improved rate performance of higher than 1000 mA h g^-1 at a high current density of 5.0 A g^-1. This unique structure design endows the electrodes with high power and long cycling stability.