Vertical Channels Design for Polymer Electrolyte to Enhance Mechanical Strength and Ion Conductivity

Polymer electrolytes are the key candidates for solid-state batteries benefiting from their intrinsic advantages over inorganic electrolytes in terms of flexibility and easy processability. However, they suffer from low ionic conductivity and poor mechanical strength, which restrict their wide utilization. Conventional ceramic fillers are used to improve the mechanical properties of polymer electrolytes but lack sufficient Li+ conductivity. In this work, a framework with vertical channels that possess fast Li+ movement is designed. It is found that the poly(ethylene oxide) (PEO) compound in the vertical channel framework benefits to improve the ionic conductivity and mechanical strength synchronously. The framework in which ionic liquids are loaded on a zirconium dioxide surface (ZrO2@ILs) helps to improve ionic conductivity by 2 orders of magnitude compared with PEO, which is due to the enhanced orientation of ion transport. By optimizing the content of ZrO2@ILs, the elastic modulus is also tripled. Therefore, the symmetric lithium battery can cycle stably for more than 800 h at a current density of 0.25 mA cm–1, whereas the lithium metal battery has a specific capacity of 135 mAh g–1 at a current density of 2C and can cycle stably for more than 200 cycles at 60 °C.