Nano-sized Li₄Ti₅O₁₂/C anode material with ultrafast charge/discharge capability for lithium ion batteries

Nano-structured Li₄Ti₅O₁₂ crystals coated with carbon layer are in situ synthesized via one-step liquid process taking advantage of low-cost sucrose as carbon source in this work. The as-prepared LTO/C particles present much larger specific surface area (58 m² g⁻¹) relative to the value of pure LTO, with a size around 13 nm in average. Its electronic conductivity of 6.56 × 10⁻⁴ S cm⁻¹ is over three orders of magnitude higher than the pure one. The composite anode displays a distinguished electrochemical charge/discharge performance, especially, quite high rate capability along with a stable cyclability. It delivers the initial discharge specific capacities of 156.7 and 142.1 mA h g⁻¹ at 40C and 60C respectively, and remains the values of 114.2 and 98.1 mA h g⁻¹ after 200 cycles. Furthermore, a capacity of 132.8 mA h g⁻¹ is delivered even at an 80C rate and the value of 82.7 mA h g⁻¹ can be maintained after 200 cycles. The ultrafast charge/discharge capability may be attributed to the shorten Li⁺ transport path in the nanosized composite and the enlarged access area with electrolyte. Additionally, the carbon coating may provide an effective conductive network among the particles promoting charge transfer.