Si/Ti3SiC2 composite anode with enhanced elastic modulus and high electronic conductivity for lithium-ion batteries

Large volume changes (similar to 300%) during cycling and low electronic conductivity of silicon (Si) always lead to the failure of the Si anode for lithium-ion batteries. In this paper, we report a facile method to fabricate Si/Ti3SiC2 composites by one-step sand-milling process. Ti3SiC2 is used as a mechanical strengthening and high conductive matrix for Si-based anode for the first time. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are conducted to characterize the structure and morphology of the Si/Ti3SiC2 composites. Capacity and cycling performance are studied by galvanostatic method. Nanoindentation test is performed to measure the elastic modulus and hardness of the electrodes. Electrochemical impedance spectroscopy (EIS) and four-probe electronic conductivity measurement are used to assess the effect of Ti3SiC2 on the electronic conductivity of Si anode. Electrochemical investigations show that both cycling stability and rate performance of Si/Ti3SiC2 anodes are significantly improved comparing with those of the pure Si anode. SEM, nanoindentation and four-probe electronic conductivity measurement results reveal that the Ti3SiC2 can not only significantly enhance the electronic conductivity of the Si/Ti3SiC2 anodes but also maintain the integrity of the electrode during cycling by markedly increasing the elastic modulus and hardness of the electrodes.