Through a hydrothermal phosphatization method synthesized NiCo and Fe-based electrodes for high-performance battery-supercapacitor hybrid device

摘要

It is a challenge to build a hybrid energy storage system by combining the power of supercapacitors with the energy of batteries. In this work, an effective and promising phosphatized method using aluminium phosphide as phosphorus source was proposed to prepare metal phosphides. The introduction of water vapor in phosphatized process not only participates in the reaction, but also accelerates the etching and phosphatization of electrode, which promotes the formation of characteristic architecture. Then, NiCo and Fe-based electrodes were synthesized through hydrothermal phosphatization. The NiCoPickel foam (NiCoP/NF) electrodes which have favorable electrochemical performance at high current densities achieved a high areal capacity (19.90 F cm(-2) at 50 mA cm(-2)) and favorable cycling stability (capacity retention of 92% at a high current density of 50 mA cm(-2) after 2000 cycles). Furthermore, we successfully built NiCoP/NF//FexPOy/IF battery-supercapacitor hybrid system with advanced electrochemical performance. The device possesses a high areal capacity of 6.28 F cm(-2), a maximum volumetric energy density of 56.11 mW h cm(-3) and power density of 0.642 W cm(-3). These results confirm that the phosphatized method is promising for the preparation of metal compounds, and the battery-supercapacitor hybrid system effectively combine the merits of supercapacitors and batteries, indicating the Fe-based electrode as a potentially candidate for next generation anode for hybrid systems.