Si/Cu/C Nanohybrid Lithium-Ion Battery Anode with in Situ Incorporation of Nonagglomerated Super-Small Copper Nanoparticles Based on Epoxy Resin

Silicon anode has a huge potential to replace graphite anode. Nevertheless, it shows poor long-term cyclic stability and rate capability due to a huge volume change upon lithiation and intrinsic semiconductor property. In this manuscript, a silicon composite with nonagglomerated super-small sized copper nanoparticles (average diameter: 7 nm) was obtained. First, the super-small copper nanoparticles (NPs) are beneficial to enhance the electron conductivity and electrochemical kinetics. Second, the copper NPs help to stabilize the electrode by absorbing mechanical stress. An amine based curing agent works as not only the solvent but also the carbon precursor. The thermosetting epoxy resin inhibits the agglomeration of the copper and silicon nanoparticles. Both silicon and copper nanoparticles are homogeneously dispersed in the carbon formed during the calcination under an inert atmosphere. The influence of the silicon and copper contents on the composition, structure, morphology, crystallinity, porosity, dispersion, and electrochemical performance of the Si/Cu/C nanohybrids are thoroughly studied by various techniques. The structure–property correlation of Si/Cu/C nanohybrids is investigated. A good balance among capacity, cyclic stability, and rate performance is achieved.