SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3449-5
The escalating demand for high-performance lithium-ion batteries (LIBs) in portable electronics and electric vehicles has driven extensive research into advanced electrolytes. Ionic liquids (ILs) and their derived electrolytes, including poly(ionic liquids), ionogels, and IL-functionalized systems, offer significant potential for enhancing the safety and electrochemical performance of LIBs due to their unique properties such as non-volatility, wide electrochemical windows, and excellent thermal stability. These properties enable safer, high-energy, and long-lasting batteries. This review conducts a thorough analysis of the physicochemical properties of ILs and their versatile applications in electrolytes, particularly emphasizing their adaptability to fulfill the specific needs of different battery systems. In liquid electrolyte systems, ILs can function as solvents, interfacial modifiers, and critical components for constructing artificial solid electrolyte interphase (SEI). In (quasi-)solid-state electrolyte systems, ILs can be polymerized to form poly(ionic liquid)s or integrated with organic, inorganic, or composite materials to develop IL-based electrolytes, demonstrating multifunctional electrochemical performance. Finally, the review critically examines the challenges and opportunities in this field, offering insightful perspectives for future advancements.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3590-8
Solid polymer electrolytes (SPEs) are promising for safer, high-energy solid-state lithium batteries, yet they suffer from low ionic conductivity (10^-5–10^-6 S/cm) and low lithium-ion transference numbers (t_Li+ ≈ 0.2) due to sluggish Li+ diffusion and incomplete salt dissociation. Polyethylene oxide (PEO) hosts exhibit high crystallinity, restricting conduction to amorphous domains, and a narrow electrochemical stability window (~3.6–3.8 V), limiting compatibility with high-voltage cathodes. This study introduces nanoscale Lewis-acid fluorides (e.g., AlF3, 5–10 wt%) into PEO–LiTFSI to address these limitations. The additive preferentially binds TFSI− anions, enhancing salt dissociation and transference number; disrupts PEO crystallinity, increasing amorphous content and segmental mobility; and forms a LiF-rich interphase that suppresses dendrites and parasitic reactions. Symmetric Li|Li cells with AlF3 cycled >3600 h without short-circuit, versus ~550 h for neat PEO. The approach extends to other polymers (polycarbonates, PVDF-HFP) and metal systems (Na, Zn, Mg), promising room-temperature conductivities beyond 10^-4 S/cm, near-unity cation transport, and dendrite-free cycling. This work establishes Lewis-acid fluorides as a versatile strategy to transform polymer electrolytes into actively engineered media for high-performance solid-state batteries.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3717-6
Poly(ethylene oxide) (PEO)-based all-solid-state polymer electrolytes (SPEs) hold significant promise for high-specific-energy and high-safety Li batteries, yet suffer from poor mechanical robustness and low Li+-conducting efficiency. Aramid nanofibers (ANFs), with exceptional mechanical strength and abundant intramolecular/intermolecular interactions, are effective additives, but their strictly symmetric interchain interactions generate a highly ordered hydrogen-bond network, producing inert aggregates that compromise electrolyte stability. Here, we construct a poly(ethylene glycol) (PEG)-mediated asymmetric interaction between ANF chains. PEG chains introduce weaker H-bonding acceptor sites, higher steric hindrance, and abundant lithiophilic groups, simultaneously disrupting strong symmetric ANF-ANF interactions and creating rapid Li-ion channels. The resulting electrolyte maintains excellent mechanical properties (yield stress of 3.25 MPa) and enables stable cycling of Li||Li symmetric cells for over 1600 h with low polarization voltage. In LCO||Li cells, the electrolyte achieves a capacity retention of 82.7% after 300 cycles at 1 C, markedly higher than the unmodified counterpart (35.5%). This synergistic optimization of interfacial compatibility and mechanical performance demonstrates a practical route toward safe, high-energy-density all-solid-state polymer batteries.