Carbon-nitrogen quantum dots modification of Li 4 Ti 5 O 12 anode material for lithium-ion batteries

Carbon-nitrogen co-modified Li4Ti5O12 (CNLTO) anode material for lithium-ion battery was synthesized by sol-gel method and two-step calcination process using tetrabutyl titanate, lithium acetate, citric acid, and chitosan as starting materials. The microstructure and morphology were characterized by XRD, XPS, SEM, and TEM. The electrochemical properties were measured by constant current charge-discharge test, CV, and EIS. The results show that the particle size of CNLTO is between 50 and 200 nm, and the particles adhere with nano-carbon-nitrogen quantum dots. The initial discharge specific capacity of CNLTO is 219.7 mAh g−1 at 0.5 C, and its capacity retention is 80.3% after 100 cycles. The discharge capacity of CNLTO is up to 140.4 mAh g−1 even at 40 C with the capacity retention of 94.8% after 100 cycles, attributed to the excellent conductivity and superfast ionic transport characteristic.