纳米CuO原位包覆的Mg_2NiH_4的电化学性能

Electrochemical performance of Mg_2NiH_4 in-situ coated with nano-CuO

研究了纳米CuO球磨原位包覆对氢化燃烧合成(HCS)产物Mg2NiH4结构和电化学性能的影响。XRD分析表明:球磨过程中,纳米CuO被Mg2NiH4还原为Cu,包覆于合金表面,提出了球磨原位包覆机制。电化学测试表明:纳米CuO球磨原位包覆提高了镁基合金氢化物电极的抗腐蚀性能,随着CuO添加量的增加和球磨时间的延长,电极的循环稳定性提高,首次放电比容量降低。添加30%CuO球磨40 h的电极,以30 mA/g的电流放电至-0.6 V,首次比容量为146 mAh/g,第10次循环(30 mA/g放电至-0.6 V,300 mA/g充电2 h)的容量保持率为48.6%。

The effect of in-situ coating with nano-CuO by mechanical milling on the structural and electrochemical performance of the hydriding combustion synthesis （HCS） product Mg2 NiH4 was investigated. XRD results showed that due to the reducibility of the HCS product Mg2NiH4,nano-CuO was reduced to Cu during milling, which was coated on the surface of Mg2NiH4.A mecha- nism of in-situ coating during milling process was presented. Electrochemical measurements indicated that the anti-corrosion cape- bility of the Mg-based alloy hydride electrode was improved by in-situ coating with nano-CuO, with the increasing of the CuO content and prolonging with the ball-milling time, the cycle stability of the electrode was improved, the initial specific discharge capaci- ty was decreased. The electrode ball-milled for 40 h with 30% nano-CuO had initial specific discharge capacity of 146 mAh/g （discharge to - 0.6 V with the current of 30 mA/g） ,the capacity retention rate was 48.6% at the 10th cycle（discharge to - 0.6 V with 30 mA/g;charge 2 h with 300 mA/g）.