Bismuth nanoparticles embedded in a carbon skeleton as an anode for high power density potassium-ion batteries

Bismuth is a promising anode for potassium-ion batteries (PIBs) due to its suitable redox potential, large theoretical capacity, and superior electronic conductivity. Herein, we report a Bi@C (Bi nanoparticles uniformly embedded in a carbon skeleton) composite anode which delivers a superior rate performance of 244.3 mA h g(-1) at 10.0 A g(-1) and a reversible capacity of 255.6 mA h g(-1) after 200 cycles in an optimized ether-based electrolyte. The outstanding electrochemical performance results from its robust structural design with fast reaction kinetics, which are confirmed by both experimental characterization studies and first-principles calculations. The reversible potassium storage mechanism of the Bi@C composite was also investigated by in situ X-ray diffraction. In addition, the full PIB cell assembled with a Bi@C composite anode and nickel-based Prussian blue analogue cathode exhibits high discharge voltage (3.18 V), remarkable power density (>10 kW kg(-1)), and an excellent capacity retention of 87.8% after 100 cycles. The results demonstrate that the PIBs with Bi anodes are promising candidates for power-type energy storage devices.

Automated summary

In this study, a Bi@C composite anode with superior rate performance and high reversible capacity was reported. The outstanding electrochemical performance is attributed to the robust structural design and fast reaction kinetics of the composite. Furthermore, the assembled PIB cell with Bi@C anode and nickel-based Prussian blue analogue cathode exhibits remarkable power performance and cycling stability.