Self-supporting and high-loading hierarchically porous Co-P cathode for advanced Al-ion battery

Abstract

Metallic cathode materials for Al-ion batteries (AIBs) are attracting more and more attention due to high intrinsic capacity. However, powdery metal-based active materials loaded on a current collector by binders are often designed. Low loading mass, small practical capacity and poor cycling stability limit the advancement of high-energy Al-ion batteries. Here, a novel self-supporting hierarchically porous cobalt phosphide (Co-P) on 3D carbon cloth (CC) as cathode for AIBs was designed and constructed by Co-P electrodeposition on gas-liquid-solid interface and heating treatment. The self-supporting hierarchically porous Co-P/CC cathode exhibits high initial discharge capacity of 257.9 mAh g−1 and maintains 85.1 mAh g−1 with a high Coulombic efficiency of 99.6% after 400 cycles at 200 mA g−1. The value is much higher than that of powdery Co2P/Ta cathode (43.7 mAh g−1 with Coulombic efficiency less than 90%). More importantly, the loading mass of self-supporting Co-P is up to 12.6 mg cm−2 and delivers extremely high areal capacity of 1072 mAh cm−2, which is more than 10 times compared with those of powdery active materials. This work provides effective metal-based cathode to develop advanced high-energy-density Al-ion battery.