Multi-scale carbon@Sb mesoporous composites activated by in situ localized electrochemical pulverization as high-rate and long-life anode materials for potassium-ion batteries†

Abstract

Hard carbon and antimony (Sb) are two promising anode candidates for future potassium-ion batteries. Herein, we successfully solve the low-capacity problem of highly conductive carbon and poor cycling stability of high-capacity Sb through uniformly dispersing and embedding sub-nano and nanoscale Sb particles (∼36.4 wt%) inside nitrogen-doped two-dimensional hard carbon nanosheets to form a multi-scale carbon@Sb mesoporous composite, denoted as Sb₃@HCNS. The electrochemical results show that the optimized Sb₃@HCNS anode exhibits an exceptional potassium-ion storage performance, delivering a reversible capacity of 580.8, 413.0, and 215.5 mA h g⁻¹ at the current density of 0.1, 1, and 4 A g⁻¹, respectively. Furthermore, it still maintains a high capacity of 382 mA h g⁻¹ at a high current density of 2 A g⁻¹ after 1000 cycles. The characterization results further manifest that the in situ localized electrochemical pulverization activation of Sb during the (de)alloying process and the pseudo-capacitive effect of good electronic conductive hard carbon nanosheets are mainly responsible for the exceptional properties of Sb₃@HCNS. Together with its controllable preparation strategy, the newly-developed Sb₃@HCNS composite is expected to be a promising anode material for high-performance potassium-ion batteries.