Metal-Rich Porous Copper Cobalt Phosphide Nanoplates as a High-Rate and Stable Battery-Type Cathode Material for Battery-Supercapacitor Hybrid Devices

In recent years, transition-metal phosphides (TMPs) have drawn increasing attention as a battery-type cathode material for battery-supercapacitor hybrid (BSH) devices owing to their superior electrochemical activity as well as a rich valence state, and the reasonably designed composition and structure of bimetallic phosphides are considered to be an efficient approach to fully utilize their advantages and overcome their defects of low rate capability and poor cycle life for potential applications. Herein, the metal-rich porous Cu-Co-P well-defined hexagonal nanoplates were synthesized via a simple hydrothermal approach and the subsequent phosphorization treatment. Thanks to the well-designed metal-rich composition and unique meso/macropore-rich structure, the Cu-Co-P electrode exhibits a large specific capacity (110.6 mA h g(-1) at 1 A g(-1)), a splendid rate performance (48.1 mA h g(-1) at 100 A g(-1)), and an outstanding cyclic property (89% of initial capacity for 10,000 cycles at 5 A g(-1)). Impressively, the as-assembled Cu-Co-P nanoplates//porous carbon (PC) BSH device shows a considerable energy/power density of 41.3 W h kg(-1)/17.625 kW kg(-1) and an exceptional cycle performance (90.1% of initial capacity for 10,000 cycles at 3 A g(-1)). This work provides a valuable reference for designing and exploiting high-property TMPs by simultaneously regulating their composition and structure.

Automated summary

This study synthesized metal-rich porous Cu-Co-P hexagonal nanoplates, demonstrating excellent electrochemical properties, rate performance, and cyclic stability. The well-designed composition and structure enabled the Cu-Co-P electrode to exhibit a large specific capacity, splendid rate performance, and outstanding cyclic property, highlighting the potential of transition-metal phosphides in BSH devices.