The urgent need for safer batteries is leading research to all-solid-state lithium-based cells. To achieve energy density comparable to liquid electrolyte-based cells, ultrathin and lightweight solid electrolytes with high ionic conductivity are desired. However, solid electrolytes with comparable thicknesses to commercial polymer electrolyte separators (~10 μm) used in liquid electrolytes remain challenging to make because of the increased risk of short-circuiting the battery. Here, we report on a polymer–polymer solid-state electrolyte design, demonstrated with an 8.6-μm-thick nanoporous polyimide (PI) film filled with polyethylene oxide/lithium bis(trifluoromethanesulfonyl)imide (PEO/LiTFSI) that can be used as a safe solid polymer electrolyte. The PI film is nonflammable and mechanically strong, preventing batteries from short-circuiting even after more than 1,000 h of cycling, and the vertical channels enhance the ionic conductivity (2.3 × 10⁻⁴ S cm⁻¹ at 30 °C) of the infused polymer electrolyte. All-solid-state lithium-ion batteries fabricated with PI/PEO/LiTFSI solid electrolyte show good cycling performance (200 cycles at C/2 rate) at 60 °C and withstand abuse tests such as bending, cutting and nail penetration.

迫切需要更安全的电池，这导致对全固态锂基电池的研究处于领先地位。为了获得与基于液体电解质的电池可比的能量密度，需要具有高离子传导性的超薄和轻质的固体电解质。然而，由于增加了电池短路的风险，因此具有与液体电解质中使用的商用聚合物电解质隔膜（〜10μm）相当的厚度的固体电解质仍然具有挑战性。在这里，我们报告了一种聚合物-聚合物固态电解质的设计，该演示用厚度为8.6μm的纳米多孔聚酰亚胺（PI）膜填充了聚环氧乙烷/双（三氟甲烷磺酰基）酰亚胺锂（PEO / LiTFSI）安全的固体聚合物电解质。PI膜不易燃，机械强度高，注入的聚合物电解质在30°C下为^-4  S cm ^-1。由PI / PEO / LiTFSI固体电解质制成的全固态锂离子电池在60°C时表现出良好的循环性能（在C / 2速率下为200次循环），并且可以经受弯曲，切割和钉子穿透等滥用测试。