Structure-Optimized Phosphorene for Super-Stable Potassium Storage

摘要

Few-layer phosphorene is a promising anode material in potassium-ionbatteries, yet suffers from poor electronic properties and large volumeexpansion during the potassiation/depotassiation process. In this study,a facile synthesis method for a high-performance phosphorene-carbonnanotubes/polyaniline ((P-CNTs)/PANI) composite is reported. The CNTsin the (P-CNTs)/PANI composite serve as electron transport channels andimprove the conductivity of phosphorene, while the PANI coating alleviatesthe structural degradation caused by the volume expansion of phosphorene.This results in super-stable, high-performance potassium storage.Structure-optimized (P-CNTs)/PANI anodes combined with a potassiumbis-(fluorosulfonyl)imide (KFSI)-based electrolyte (3 m KFSI/dimethoxyethane)exhibits a high reversible capacity of 642.7 mAh g~(?1) at 50 mA g~(?1) and amaximum reversible capacity of 417.6 mAh g~(?1) at 500 mA g~(?1) during stablecycling. A capacity retention rate of 94 is observed after 500 stable cycles,while the average capacity decay rate per cycle is as low as 0.012. Moreover,the anode exhibits an excellent rate performance of 147.8 mAh g~(?1)at 2000 mA g~(?1). The results of the effect of the PANI coating show that(P-CNTs)/PANI has a more stable structure and superior performance thanP-CNTs.