In-situ implanted carbon nanofilms into lithium titanate with 3D porous structure as fast kinetics anode for high-performance dual-ion battery

Abstract

Dual-ion battery (DIB) paring lithium titanate (LTO) anode with graphite cathode is attractive for energy storage applications owing to its merits of environmental friendly, excellent cyclic stability, and good safety. However, the specific capacity of the LTO-DIB is still relatively low (<50 mAh g−1), which ascribe to the mismatching reaction kinetics between the graphite cathode and LTO anode for the low conductivity of LTO. In this work, we propose a strategy of in-situ implanting carbon nanofilms into LTO composite and simultaneous formation of 3D porous structure (LTO@3DC) via combining organic molecule coupling, freeze drying and pyrolysis processes. Consequently, the diffusion coefficient of Li+ ions is dramatically enhanced from ~2 × 10−12cm2 s−1 for pristine LTO to ~6 × 10−12cm2 s−1 for the 3D porous LTO@3DC due to the 3D porous Li+ ions diffusion pathways and conductive carbon skeleton of the LTO@3DC. Further, a DIB configuration combining this fast kinetics LTO@3DC anode and environmental friendly expanded graphite (EG) cathode is constructed (LTO@3DC-DIB), which exhibits a high specific capacity (110 mAh g−1 at 2 C), good rate capability up to 10 C, and long cycling stability with a capacity retention of ~100% after 700 cycles under 5 C, among the best cycle performance of the reported DIBs.