Synthesis and electrochemical characterization of stoichiometric Cu2S as cathode material with high rate capability for rechargeable lithium batteries
Synthesis and electrochemical characterization of stoichiometric Cu2S as cathode material with high rate capability for rechargeable lithium batteries
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DOI：
10.1016/j.jpowsour.2016.09.047
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发表时间：
2016-11
影响因子：
9.2
通讯作者：
G. Kalimuldina;I. Taniguchi
中科院分区：
文献类型：
--
作者：
G. Kalimuldina;I. Taniguchi
采用喷雾热分解（SP）法，研究了不同Cu/S摩尔比、不同合成温度和退火温度下，硫化铜（Cu 2S）的合成。通过在400 °C下SP制备然后在460 °C下退火2小时的样品显示化学计量的Cu/S比，这通过电感耦合等离子体发射光谱法验证。X射线衍射（XRD）结果表明，样品为单斜晶系，空间群为P21/c。通过循环试验和微分容量分析研究了化学计量比Cu 2S电极的电化学性能。涂敷在Al箔上的Cu 2S电极在0.1C的充放电速率下表现出335 mAh g-1的首次放电容量，这对应于其理论容量的99.4%。但由于Cu对Al箔的腐蚀，其可逆性较差。相比之下，涂覆在Cu箔上的Cu 2S电极在高达30 C的高充放电速率下表现出稳定的循环性能。非原位XRD分析表明，从单斜Cu 2S结构的空间群P21/c的四相Cu1.96S结构的空间群P43212的相变逐渐进行在最初的五个循环。
Synthesis of stoichiometric copper sulfide (Cu2S) was studied by spray pyrolysis (SP) with heat treatment for different Cu/S molar ratios in the starting solution and different synthesis and annealing temperatures. The sample prepared via SP at 400 °C and then annealed at 460 °C for 2 h showed the stoichiometric Cu/S ratio, which was verified by inductively coupled plasma-optical emission spectroscopy. The X-ray diffraction (XRD) peaks of the sample were indexed to the monoclinic structure with space groupP21/c. The electrochemical performance of the stoichiometric Cu2S electrode was investigated by a cycle test and differential capacity analysis. The Cu2S electrode coated on an Al foil exhibited a first discharge capacity of 335 mAh g−1at a charge-discharge rate of 0.1 C, which corresponds to 99.4% of its theoretical capacity. However it showed poor reversibility owing to the corrosion of Al foil by Cu. In contrast, the Cu2S electrode coated on Cu foil demonstrated stable cyclability at high charge-discharge rates of up to 30 C. Exsitu XRD analysis showed that a phase transformation from the monoclinic Cu2S structure with the space groupP21/cto the tetragonal Cu1.96S structure with the space groupP43212 gradually progressed during the initial five cycles.