Three‐Dimensional Hierarchical Ternary Nanostructures Bismuth/Polypyrrole/CNTs for High Performance Potassium‐Ion Battery Anodes

Comprehensive Summary In recent years, the anode materials of bismuth(Bi)‐based potassium ion batteries with high theoretical capacity and suitable potassium ion insertion potential have attracted extensive attention. However, due to the volume expansion of Bi, the performance of Bi‐based anode materials is not ideal during potassium ion (de)intercalation. In order to solve these problems, we report a three‐dimensional (3D) ternary bismuth nanoparticles/conductive polymers/carbon nanotubes (Bi/PPy/CNT) hybrid anode material for K‐ion batteries. At a current density of 100 mA·g –1 , its reversible capacity reaches 302 mAh·g –1 after 200 cycles, while it reaches 195.7 mAh·g –1 after 600 cycles at 1 A·g –1 . Its excellent performance is attributed to the hydrogel network which provides a range of electron transport networks and high porosity. Carbon nanotubes are used as electron enhancers to reduce the volume expansion of Bi particles during the reaction. This study provides a prerequisite for expanding the application of 3D ternary materials.