Plicated mesoporous silica nanoparticles integrated poly(ionic liquids) composite polymer electrolyte for solid‐state lithium-ion batteries

Gel polymer electrolytes (GPEs) are valuable in preparing lithium-ion batteries (LIBs) with high safety, high energy density and high cycle life. However, the liquid component increases the performance of GPEs while decreasing their mechanical strength. For improving the mechanical strength and ionic conductivity of GPEs, one plicated mesoporous silica nanoparticles (PMSN) was prepared and introduced into the poly(ionic liquids) electrolyte to prepare a composite poly(ionic liquids) electrolyte (PIL-GPE@PMSN). PMSN with a high specific surface area could increase its contact area with the polymer electrolyte to form more Li+ migration channels. With the introduction of PMSN, the ionic conductivity of PIL-GPE@PMSN is elevated to 1.76 × 10−3 S cm−1, and the maximum tensile stress increased to 1.25 MPa. In addition, the good interfacial properties reduce the interfacial impedance between the electrolyte and electrodes, so Li/PIL-GPE@PMSN-5 %/LiFePO4 batteries exhibit greater discharge capacity and stable cycling performance. Li/PIL-GPE@PMSN-5 %/LiFePO4 batteries show high capacity of 147 mAh g−1 under current density of 0.5 C, and the capacity retention rate is greater than 94 % after 200 cycles. Moreover, Li/electrolyte/NCM811 batteries with LiNi0.8Co0.1Mn0.1O2 (NCM811) positive electrode also exhibit ideal rate performance and long cycle charge-discharge performance. The prepared PIL-GPE@PMSN exhibits the potential to improve the safety of high-energy density LIBs.