采用水热法合成Co-S合金,并对工艺参数进行了优化。通过XRD、SEM分析了合金的表面形貌及物相的变化；用恒电流充放电测试、循环伏安以及交流阻抗对合金进行了电化学性能表征。结果表明：反应溶液填充度为70%,160℃保温12 h制得的Co-S合金含有Co与Co9S8两相,颗粒结晶度好,呈厚约50 nm的交叉薄片状。在150 mA/g的充放电电流下, Co-S合金最大放电容量可达536 mAh/g,循环50次的容量保持率为77.4%。Co-S合金电极充放电时主要发生Co与Co(OH)2之间的氧化还原反应,部分Co的不可逆脱溶,导致活性物质减少,电极容量衰减。
The Co-S alloys were prepared by a hydrothermal method and the process parameters were optimized. The surface morphology and phase structure of Co-S alloys were characterized by SEM and XRD. The electro-chemical properties of Co-S alloys were investigated by galvanostatic charge and discharge tests, cyclic voltam-metry and AC impedance. The results indicated that the as-prepared Co-S alloy, which was synthesized using a 70%packing volume of the reaction solution at 160℃ for 12 h, showed good crystallinity. This alloy consisted of me-tallic Co and Co9S8 phases with a cross-linked lamellar morphology of about 50 nm in thickness. It possessed a maximum discharge capacity of 536 mAh/g at charge and discharge current density of 150 mA/g and a good cycling stability with capacity retention rate of 77.4%after 50 cycles. The redox reactions between Co and Co(OH)2 were the main reaction during charge and discharge. Partial dissolution of Co reduced the active material and led to ca-pacity decay.
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