Reinforce the Adhesion of Gel Electrolyte to Electrode and the Interfacial Charge Transfer via In Situ Electrospinning the Polymeric Nanofiber Matrix

The adhesion of a gel electrolyte to the electrode is one of the key factors to the electrochemical performance of lithium‐ion batteries (LIBs). Herein, gel electrolyte is prepared on the LiFePO4 electrode through in situ electrospinning the poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐HFP) nanofiber matrix, followed by lithium salt solution loading. The interfacial interactions between the in situ electrospun PVdF‐HFP matrix and LiFePO4 electrode before and after gelation are studied using dynamic thermomechanical analysis and scanning electron microscopy. The results demonstrate that the as‐prepared gel electrolyte can adhere tightly onto the LiFePO4 electrode. LIBs (half coin cells) are assembled using the as‐obtained gel electrolyte to evaluate their electrochemical properties. The results show that the lithium‐ion and electron transfer rates crossing the interface between gel electrolyte and LiFePO4 electrode are enhanced. The electrochemical performances of the half coin cells, including specific capacity, rate capability, and cycle stability, are improved significantly. The gel electrolyte prepared through in situ electrospinning the poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐HFP) nanofiber matrix on LiFePO4 electrode followed by lithium salt solution loading shows decent interfacial adhesion to the electrode. The assembled LiFePO4 half coin cell using in situ PVdF‐HFP gel electrolyte exhibits improved charge transfer capability, rate performance, and cycle stability, compared with that using freestanding one.