Free-standing and binder-free sodium-ion electrodes based on carbon-nanotube decorated Li4Ti5O12 nanoparticles embedded in carbon nanofibers

Abstract

Free-standing CNT/Li₄Ti₅O₁₂/C composite nanofibers with uniformly dispersed Li₄Ti₅O₁₂ nanoparticles and CNTs in a one-dimensional (1D) carbon nanofiber matrix were developed for high-power electrode materials in Na-ion batteries. The carbon nanofibers act as a matrix to enable better dispersion of Li₄Ti₅O₁₂ and restrict the Li₄Ti₅O₁₂ particle size at the nanoscale. The CNTs were introduced to construct a three-dimensional (3D) network between Li₄Ti₅O₁₂ particles and to enhance the conductivity of the electrode, thereby realizing the full potential of the active materials. Free-standing CNT/Li₄Ti₅O₁₂/C composite nanofibers achieved a discharge capacity of 119 mA h g⁻¹ after 100 cycles at a current density of 100 mA g⁻¹, corresponding to 95.2% of the initial charge capacity (125 mA h g⁻¹) and a better rate capability (77 mA h g⁻¹ at 500 mA g⁻¹). This design could also be further extended to other electrode materials, which promises to promote the development of next-generation Li-ion batteries or Na-ion batteries.