Industrialization progress of polymer-based solid-state <?A3B2 pi6?>lithium-ion batteries

Solid-state lithium-ion batteries represent a groundbreaking advancement in energy storage technology, driven by the imperative to replace flammable liquid electrolytes while achieving energy densities exceeding 500 Wh kg−1 and charge/discharge lifespan beyond 2000 cycles. This review offers a comprehensive evaluation of the industrialization of polymer-based solid-state lithium-ion batteries, focusing on three critical challenges: high interfacial impedance caused by poor solid–solid contact, insufficient ionic conductivity at room temperature (typically ​−4 S cm−1 in conventional systems), and mechanical degradation resulting from electrode volume changes. Through a systematic comparison of inorganic ceramics (e.g., oxides, sulfides, and chlorides), organic-inorganic composites, and polymer electrolytes, we identify material-specific bottlenecks impeding large-scale manufacturing.Inorganic ceramic electrolytes, such as Li7La3Zr2O12 (LLZO) and Li10GeP2S12 (LGPS), demonstrate impressive bulk ionic conductivities (>10−2 S cm−1 for LGPS) and outstanding thermal stability (>1000℃ for LLZO). However, their commercial potential is limited by inherent brittleness (e.g., LLZO fracture toughness of 1.25 MPa m1/2), high material costs (e.g., Ta-doped LLZO exceeding 1500 USD kg−1), and significant interfacial impedance (>103 Ω cm2). Sulfide electrolytes offer liquid-like ionic conductivities (~1.2×10−2 S cm−1), but face critical drawbacks including irreversible oxidation at high voltages, moisture-induced H2S generation, and intrinsic flammability, as recently confirmed by BYD’s thermal abuse tests, which demonstrated violent thermal runaway above 150℃.Polymer electrolytes fabricated via in situ polymerization have emerged as one of the most scalable solutions, largely due to their compatibility with existing battery manufacturing infrastructure and ability to form ultra-conformal electrode-electrolyte interfaces with low impedance. This method involves injecting low-viscosity precursors (e.g., acrylate or vinyl carbonate monomers) into batteries, followed by UV or thermal curing to create solid networks capable of accommodating over 300% volume expansion of silicon anodes. Recent advances in quasi-solid polymer electrolytes (QSPEs) incorporating fluorinated solvents (e.g., fluoroethylene carbonate, FEC) or ionic liquids (e.g., [BMIM][TFSI]) have achieved room-temperature ionic conductivities as high as 2.95×10−3 S cm−1 with battery operational stability spanning –40 to 105℃. Industrial validations underscore QSPEs’ potential: QSPEs with gradient Li+ solvation structures were engineered to reduce Li+ migration activation energy to 0.18 eV, enabling 4 C fast charging with 95.52% capacity retention (relative to 0.2 C) and over 3500 cycles with 77.2% capacity retention. Meanwhile, a French manufacturer developed solid-state batteries using 20 μm lithium metal anodes delivering energy densities of 450 Wh kg−1 at 105℃ without thermal management. Additionally, a Beijing-based company’s polymer–oxide composite electrolytes have passed rigorous nail penetration and crush tests at energy densities exceeding 300 Wh kg−1. Notably, cells developed by the Wuhan company survived 5.8 mm ballistic impacts without thermal runaway—A safety milestone unattainable with conventional liquid electrolytes.This review highlights the manufacturing advantages of polymer electrolytes, particularly their compatibility with the roll-to-roll processing, which can significantly reduce production costs compared to sulfide- or oxide-based alternatives. Policy initiatives such as China’s mandate for 500 Wh kg−1 batteries by 2025 under the New Energy Vehicle Industry Development Plan (2021–2035), alongside the European Union’s Battery 2030+ program supporting gigafactory expansion, are accelerating commercialization efforts. Future progress will depend on the synergistic integration of AI-guided copolymer design (e.g., topology-engineered Li+ hopping pathways), in situ interfacial diagnostics via cryo-electron microscopy, and dynamic covalent chemistry (e.g., boronic ester exchange) to enable self-healing electrolyte systems. With the solid-state battery market projected to reach approximately ¥10 trillion (USD 1.4 trillion) by 2030, polymer-based technologies are well-positioned to lead electric vehicles, grid-scale storage, and aerospace applications—Charting a definitive path toward safe, high-energy-density, and sustainable energy storage solutions. This review aims to provide valuable insights and strategic guidance for advancing next-generation battery technologies.