水分对NCA/石墨软包电芯的影响

Impact of moisture on NCA/Graphite pouch cells

研究了水分对NCA/石墨软包电芯的影响。通过测试电芯化成产气、电化学性能和高温存储性能来表征水分对NCA/石墨软包电芯的影响。气体分析结果表明,CO2含量随着NCA极片水分含量的增加而增加;电化学性能测试结果和高温存储性能结果表明,NCA极片水分含量对电芯的电化学性能和高温存储性能有非常大的影响。从循环后极片的XRD结果可以看出,过高的NCA极片水分含量会严重破坏材料的层状结构并导致锂镍混排加剧。循环后NCA极片的S EM图表明NCA极片水分含量越高,对材料结构破坏越严重。循环后负极极片表面状态和负极极粉ICP结果表明,过高的NCA极片水分含量会加大过渡金属的溶出,同时还会造成负极析锂。所有的结果表明,NCA极片水分对软包电芯有不利影响。

The influence of moisture content on NCA/Graphite pouch cells was circumstantial and systematical investigated.The gas production,electrochemical performance and high-temperature storage of the cells were examined to characteristic the effect of moisture on NCA/graphite soft cladding cells.Gas analysis shows that the content of CO2 will increase with the increase of NCA cathode moisture.The result of electrochemical performance and shows that the cathode moisture does affect the electrochemical performance and the high temperature storage performance of the pouch cells.The XRD results show that higher moisture will seriously destruct the layer structure of cathode materials and result in cation mixing.The scanning electron microscope(SEM)images and the crosssectional SEM images of cathode show that the structure of cathode materials is seriously destructed with the increase of moisture.Visual inspection and inductively coupled plasma(ICP)results of anode show that high moisture increases the dissolution of transition metals and the deposition of Li metal.All results show that the moisture has a negative effect on the performance of the pouch cells.