Ti3SiC2 modified Li3V2(PO4)3/C cathode materials with simultaneous improvement of electronic and ionic conductivities for lithium ion batteries

Abstract Li 3 V 2 (PO 4 ) 3 /C (LVP/C) is synthesized by an improved sol–gel method and modified with various amounts of Ti 3 SiC 2 (TSC). It is found that both electronic and ionic conductivities are increased simultaneously with one single addition due to the nanolaminated structure of TSC. TSC not only constitutes continuous electron pathways via a “point-to-plane” conducting mode, which improves the electronic conductivity, but also enhances lithium ionic conductivity. Therefore, electrochemical performances of TSC-modified samples are significantly improved. TSC-modified samples exhibit improved cyclic stability, rate performance and initial discharge capacity at high rates. An extremely low charge transfer resistance (5.57 Ω) and significantly reduced polarization were obtained. The 4 wt% TSC-modified LVP/C sample exhibits the best electrochemical performances in the voltage range of 3.0–4.8 V, especially at high rates. It shows initial discharge capacity of 114.5 mAh g −1  at 10 C, while the discharge capacity of the pristine sample is only 37.2 mAh g −1  at the same rate. The 4 wt% TSC-modified LVP/C sample holds capacity retention of 88.5% at 10 C after 200 cycles, which is much higher than that of pristine one. A model of double-decker bus is proposed to understand the significant improvements of both electronic and ionic conductivities.