Nonmetallic Se/N Co-Doped Amorphous Carbon Anode Collaborates to Realize Ultra-High Capacity and Fast Potassium Storage for Potassium Dual-Ion Batteries

Heteroatom doping in carbon-based anode materials is crucial to improve their capacity and promoting the practical application of low-cost potassium-ion batteries (KIBs). Herein, the selenium/nitrogen co-doped amorphous carbon nanocluster (SeN-ACN) anodes exhibit an ultra-high reversible capacity of 621 mAh g-1 at 0.75 C (225 mA g-1) and a capacity retention of 93% after 2000 cycles at 5 C, which represent a remarkable achievement in potassium storage in nonmetallic doped carbon materials. This is attributed to the synergistic effects of Se/N co-doping and their anchoring effects on potassium ions. As a proof of concept, a potassium-based dual-ion battery (K-DIB), which consists of a SeN-ACN anode and low-cost graphite cathode, demonstrates a high reversible capacity of 118 mAh g-1 at 150 mA g-1 with a high cut-off voltage of 5.2 V. Moreover, it presents excellent long-term cycling performance, with 70% capacity retention after 500 cycles, among the best reported results of K-DIBs. Thanks to the synergistic and anchoring effect of Se/N co-doping in amorphous carbon nanoclusters, the SeN-ACNs-based KIB half-cells demonstrate high capacity of 621 mAh g-1 at 0.75 C with high-capacity retention of 93% after 2000 cycles at 5 C. Furthermore, the integration of SeN-ACNs/EG K-DIBs also exhibits a high capacity of 118 mAh g-1 and remarkable cycling performance.image