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

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 Li₄Ti ₅O₁₂ and restrict the Li₄Ti₅O ₁₂ particle size at the nanoscale. The CNTs were introduced to construct a three-dimensional (3D) network between Li₄Ti ₅O₁₂ 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.