Abstract
Electrospun nanofibrous separators,despite lacking superior mechanical strength,have gained widespread attention with high poros-ity and facile processing.Herein,utilizing the fact that thermal imidization temperature of poly(amic acid)(PAA)into polyimide(PI)coincides with the pre-oxidation temperature of polyacrylonitrile(PAN)into carbon fiber,we proposed a new cross-electrospinning strategy to obtain a com-posite nanofibrous separator(PI/oPAN)randomly interwoven by PI and pre-oxidized PAN(oPAN)nanofibers,via synchronously electrospinning the PAA and PAN onto the same collector and then heat-treating for 2 h at 300 ℃.The resultant PI/oPAN separator was able to preserve high porosity(71.7％),electrolyte wettability and thermal stability of PI nanofibrous membrane,and surprisingly exhibited high mechanical strength,being 3 times of PI,which mainly because of the numerous adhesion points generated by the melting of PAN in the pre-oxidation process.Mean-while,the polar groups of oPAN and 3D fibrous network enhanced the PI/oPAN separator's ionic conductivity and Li+transference number,ren-dering the corresponding cell with more stable cycling performance than cells assembled with pure PI,PAN or commercial PP separator.There-fore,this work might provide a new avenue for the ongoing design and further development of LIB separators capable of high safety and high performance.
维普
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