Adjusting the interface structure of graphdiyne by H and F co-doping for enhanced capacity and stability in Li-ion battery

Abstract

The 18–C triangular ring structure of graphdiyne (GDY) can form three-dimensional channel between layers and make GDY an excellent anode material for lithium ion batteries (LIBs). The stable solid electrolyte interface (SEI) film and strong C–F bond formed by fluoride can forcefully enhance the cycle stability in LIBs. Additionally, the stable synthesis of hydrogen-containing carbon material reduces cost and the effective lithium storage of H increases specific capacity. Herein, we propose a strategy of H and F positioning balanced co-doped GDY, combining the lithium storage contributions of H and F elements and achieving an extraordinarily high capacity of 2050 ​mA ​h g−1 at 50 ​mA ​g−1 and only 23% reduction after even 8000 cycles. The fibrous network porous structure can be formed and generate excellent electrolyte infiltration and interface stability with SEI film when H and F is evenly co-doped. This work provides approach to interface structure adjustment that effectively improved lithium storage stability. Besides, the combination approach of positioning substitution and co-doping contributes to high lithium storage capacity and provides reference for elements co-doping.