Unique CNTs-chained Li4Ti5O12 nanoparticles as excellent high rate anode materials for Li-ion capacitors

Composite anode materials with a unique architecture of carbon nanotubes (CNTs)-chained spinel lithium titanate (Li4Ti5O12, LTO) nanoparticles are prepared for lithium ion capacitors (LICs). The CNTs networks derived from commercial conductive slurry not only bring out a steric hindrance effect to restrict the growth of Li4Ti5O12 particles but greatly enhance the electronic conductivity of the CNTs/LTO composites, both have contributed to the excellent rate capability and cycle stability. The capacity retention at 30 C (1 C = 175 mA g(-1)) is as high as 89.7% of that at 0.2 C with a CNTs content of 11 wt%. Meanwhile, there is not any capacity degradation after 500 cycles at 5 C. The LIC assembled with activated carbon (AC) cathode and such a CNTs/LTO composite anode displays excellent energy storage properties, including a high energy density of 35 Wh kg(-1) at 7434 W kg( 1), and a high capacity retention of 87.8% after 2200 cycles at 1 A g(-1). These electrochemical performances outperform the reported data achieved on other LTO anode-based LICs. Considering the facile and scalable preparation process proposed herein, the CNTs/LTO composites can be very potential anode materials for hybrid capacitors towards high power-energy outputs.

Automated summary

Composite anode materials with a unique structure of carbon nanotubes (CNTs)-chained spinel lithium titanate (LTO) nanoparticles were prepared for lithium ion capacitors (LICs). The CNTs networks derived from commercial conductive slurry not only restricted the growth of LTO particles but also significantly enhanced the electronic conductivity of the CNTs/LTO composites, contributing to excellent rate capability and cycle stability. The LIC assembled with AC cathode and CNTs/LTO composite anode exhibited excellent energy storage properties, including high energy density and capacity retention after cycles.