Ball-Cactus-Like Bi Embedded in N-Riched Carbon Nanonetworks Enables the Best Potassium Storage Performance

The potassium-ion battery (PIB) has emerged as a promising alternative to lithium-ion batteries. The major challenges confronted by PIB anodes lie in sluggish kinetics and poor cycling stability owing to the inherent large K+ size. Here, a hybrid of ball-cactus-like Bi nanospheres embedded in 3D N-riched carbon nanonetworks (Bi NSs/NCNs) is designed and synthesized by electrospinning. As an anode, Bi NSs/NCNs exhibits an unprecedented rate (489.3 mAh g(-1) at 50 A g(-1)) and long-cycling performance (457.8 mAh g(-1) at 10 A g(-1) after 2000 cycles), outperforming all reported PIB anode materials. Such outstanding performance mainly originates from the stable solid-electrolyte interface formed in the glyme-based electrolyte and the unique interconnected porous nanostructure, both of which contribute to fast kinetics and high pseudocapacitive contributions upon cycling.