Solid-state battery (SSB) has a new application prospect in the fields of safe energy storage, but the solid electrolyte usually fails to maintain excellent ionic conductivity, good mechanical properties and close interfacial contact with the electrode materials simultaneously. A newly-designed poly(ionic liquid)-based quasi solid electrolyte (PIL-QSE) is prepared via one-step in-situ cross-linked polymerizing 1-vinyl-3-dodecylimidazolium bis(trifluoromethanesulfonyl) imide (VDIM-TFSI), which is filled in poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) porous membrane prepared via phase inversion. The leakage-free PIL-QSE containing a compact cross-linked network structure exhibits optimal performances with outstanding flexibility, favorable thermal stability and improved electrochemical performances including a high room-temperature ionic conductivity of 0.70 mS cm⁻¹, a superior electrochemical window up to 5.0 V as well as a high lithium ion transference of 0.52. Furthermore, the PIL-QSE can suppress dendrite formation leading to a good battery performance. The LiFePO₄|PIL-QSE|Li cells can maintain a discharge capacity 140.7 mAh g⁻¹ at 0.05 C with 99.8% coulomb efficiency after 200 cycles and 125.9 mAh g⁻¹ at 0.1 C with 98.9% capacity contention after 100 cycles at 25 °C. Because of the flexibility of PIL-QSE, the pouch-type battery based on PIL-QSE cannot only light the red LED lamp in a normal state, but also in a bended/cut state. Both of the excellent performance and easy fabrication of PIL-QSE make it potentially as one of the most promising electrolyte materials for SSPB.

固态电池（SSB）在安全的能量存储领域中具有新的应用前景，但是固态电解质通常无法保持优异的离子导电性，良好的机械性能以及与电极材料的紧密界面接触。通过一步一步原位交联聚合1-乙烯基-3-十二烷基咪唑双（三氟甲磺酰基）酰亚胺（VDIM-TFSI），制备了一种新设计的基于聚离子液体的准固体电解质（PIL-QSE），将其装入通过相转化制得的聚偏二氟乙烯-六氟丙烯（PVdF-HFP）多孔膜中。包含紧凑的交联网络结构的无泄漏PIL-QSE具有最佳性能和出色的灵活性，^-1，高达5.0 V的优异电化学窗口以及0.52的高锂离子迁移率。此外，PIL-QSE可以抑制枝晶形成，从而具有良好的电池性能。LiFePO ₄ | PIL-QSE | Li电池在200循环后，在0.05摄氏度下可保持140.7 mAh g ^-1的放电容量，库仑效率为99.8％；在200循环后，在0.1摄氏度下可保持125.9 mAh g ^-1的放电容量，在9个循环中可保持98.9％ ℃。由于PIL-QSE的灵活性，基于PIL-QSE的袋式电池不仅可以在正常状态下点亮红色LED灯，而且还可以在弯曲/切割状态下点亮红色LED灯。PIL-QSE的优异性能和易制造性使其潜在地成为SSPB最有希望的电解质材料之一。