一种基于PEO-PEG-Al_(2)O_(3)的固态锂离子电池

Asolid-state lithium-ion battery based on PEO-PEG-Al_(2)O_(3)

PEO基电解质的低离子电导率是由环氧乙烷链段进行自发结晶引起的,这里采用共混和交联的方法,利用氧化物Al_(2)O_(3)和聚环氧乙烷(PEO)共混以打乱PEO晶相的规则排列,利用小分子聚乙二醇(PEG)和PEO交联以增加更多的游离链段,同时增强PEO主链的塑性。在50℃下测试结果表明,PEO-PEG-Al_(2)O_(3)的离子电导率为2.19×10^(-4)S/cm,可在0.1 mA/cm^(2)稳定电镀剥离200 h左右,组装的磷酸铁锂(LFP)电池在0.1 C时放电比容量约为131 mAh/g,且能保持较高的库伦效率;此外,通过SEM发现,改进的PEO-PEG-Al_(2)O_(3)电解质表面缺陷少,在循环时能适当地减缓锂枝晶的生长速度。

The low ion conductivity of the PEO-based electrolyte is mainly due to the higher crystallinity.Here,through blending and crosslinking,the oxide Al_(2)O_(3)is used to disrupt the regular arrangement of the PEO crystal phase,and the small molecule polymer PEG is used to obtain more free chain segments,while enhancing the plasticity of the PEO main chain.The test results at 50℃show that the ionic conductivity of PEO-PEG-Al_(2)O_(3)is 2.19×10^(-4)S/cm,which can be stably electroplated and peeled for about 200 h at 0.1 mA/cm^(2).The assembled LFP battery has an impressive specific capacity(~131 mAh/g)at 0.1 C and a stable coulombic efficiency.In addition,it is found through SEM that the improved PEO-PEG-Al_(2)O_(3)electrolyte has fewer surface defects and can appropriately slow down the growth rate of lithium dendrites during cycling.