正极集流体对可充镁电池电化学性能的影响

以目前常用的Chevrel相Mo₆S₈作为正极材料, 涂覆在不同集流体(不锈钢、镍、铜、钛) 上, 以镁为负极,研究了在(PhMgCl)₂-AlCl₃/四氢呋喃(简称THF)“二代”电解液中集流体对可充镁电池电化学性能的影响. 恒流放电-充电结果显示在不锈钢集流体上电池电压极化最小, 并且具有较好的循环稳定性; 镍、铜次之; 钛集流体上的极化最大, 循环稳定性也最差. 并通过对比放电-充电循环前后电极和集流体表面的微观结构, 探讨了集流体对电池性能显著影响的原因. 电解液对集流体会造成腐蚀, 不同集流体在电解液中的稳定性有差异; 正极材料涂覆在不同集流体上, 电极表面状况有差异; 负载活性材料后集流体发生腐蚀的电位有所降低, 使集流体更易受到电解液的腐蚀.

Effects of Cathode Current Collectors on the Electrochemical Performance of Rechargeable Magnesium Batteries

The effects of different cathode current collectors (stainless steel, nickel, copper, and titanium) on the electrochemical performance of rechargeable magnesiumbatteries were investigated. Chevrel phase Mo₆S₈ acted as the cathode, (PhMgCl)₂- AlCl₃/tetrahydrofuran (THF) (the second generation electrolyte) as the electrolyte, and magnesium as the anode. Constant current discharge-charge results indicated that the electrochemical polarization of the electrode on stainless steel was the smallest and its cycling stability was the best, followed by nickel, copper, and titanium. Microstructure analyses for the electrodes and current collectors before and after discharge-charge were analyzed to investigate the differing electrochemical performance. The electrolyte corroded the current collectors to differing degrees. The surfaces of the electrodes differed after coating the active material on different current collectors. The corrosion potentials of the current collectors decreased after loading the active material. This resulted in the current collectors being more susceptible to corrosion by the electrolyte.