Construction of Bi/Bi2O3 particles embedded in carbon sheets for boosting the storage capacity of potassium-ion batteries.

ABSTRACT

Bismuth-based materials have attracted interest in potassium-ion batteries (PIBs). However, the large volume expansion prevents further use of bismuth-based materials for potassium storage. This work employs a two-step synthesis method to innovatively synthesize of Bi/Bi2O3 nanoparticles assembled on N-doped porous carbon sheets (Bi/Bi2O3@CN). The layered structures with uniformly shaped and N-doped porous carbon skeleton buffer the expansion of Bi and the Bi/Bi2O3 particles increase the capacity of potassium storage. In brief, the Bi/Bi2O3@CN served as anode in half-cell of PIBs have a good rate capacity of more than 234.7 mAh/g at 20 A/g. The specific capacity retention was 73 % compared with 322.16 mAh/g at 1 A/g, demonstrating good holding capacity for diverse current densities. The cycle also displays 163 mAh/g after 1500 cycles at 2 A/g in the KPF6 metal salt solution, showing its potential as one of the anode materials in PIBs.