Polymer Electrolyte Systems for Lithium Battery Applications

Polymer electrolyte systems have emerged as a promising route to safer, more flexible and high‐energy‐density lithium batteries by replacing volatile liquid electrolytes with solid or quasi‐solid media. These systems typically employ a polymer matrix—commonly polyethylene oxide or related backbones—into which lithium salts are dissolved or gelled. Solid polymer electrolytes offer intrinsic safety and mechanical robustness but are often limited by low room‐temperature ionic conductivity. Gel polymer electrolytes combine liquid‐like conductivity with a stabilised polymer scaffold, while composite polymer electrolytes integrate inorganic fillers or nanosheets to disrupt polymer crystallinity, enhance ion transport channels and improve interfacial contact with electrodes. Recent advances have addressed challenges such as dendrite suppression, limited Li‐ion transference number and electrode–electrolyte interphase stability through materials design, supramolecular architectures and interfacial engineering. The result is a growing portfolio of polymer electrolytes capable of supporting high‐rate cycling, wide electrochemical windows and long‐term stability, paving the way for next‐generation all‐solid‐state and hybrid lithium battery technologies.

Research from Nature Portfolio

Innovative composite membranes assembled from high‐modulus aramid nanofibres and a polyethylene oxide matrix have demonstrated simultaneous enhancement of mechanical strength and ionic conductivity, effectively suppressing lithium dendrite penetration under extreme discharge conditions. A supramolecular polymer electrolyte design employs orthogonal hydrogen‐bonding and ion‐conducting domains to decouple mechanical toughness from ionic transport, yielding materials that are both highly stretchable and capable of supporting robust Li‐ion flux. Ultraviolet‐induced co-polymerisation of ethylene oxide chains with tetraglyme plasticiser has produced all-ethylene oxide networks exhibiting ambient‐temperature ionic conductivities above 0.1 mS cm−1, high Li transference numbers and a wide electrochemical stability window, while maintaining interfacial stability with lithium metal.

Polymer Electrolyte Systems for Lithium Battery Applications publication trend

The graph below shows the total number of articles in polymer electrolyte systems for lithium battery applications across all publications each year (not limited to Nature Index journals).

Technical terms

Solid polymer electrolyte: A solvent‐free polymer matrix containing dissolved lithium salt that conducts ions through segmental polymer motion.

Gel polymer electrolyte: A semi‐solid system in which a polymer scaffold is swollen by liquid electrolyte, combining liquid‐phase conductivity with structural integrity.

Composite polymer electrolyte: A polymer electrolyte incorporating inorganic fillers or nanosheets to enhance ionic conductivity, mechanical strength and interfacial stability.

Ionic conductivity: A measure of the ability of ions to migrate through the electrolyte, typically expressed in siemens per centimetre (S cm−1).

Transference number: The fraction of total current carried by lithium ions in an electrolyte, indicating the efficiency of charge transport.

Dendrite: Needle‐like lithium deposits that can form during cycling and risk short-circuiting by penetrating separators or electrolyte layers.

References

1. The Critical Role of Fillers in Composite Polymer Electrolytes for Lithium Battery. Nano-Micro Letters (2023).
2. Fluorinated boron nitride nanosheet enhanced ultrathin and conductive polymer electrolyte for high‐rate solid‐state lithium metal batteries. Interdisciplinary Materials (2023).
3. A dendrite-suppressing composite ion conductor from aramid nanofibres. Nature Communications (2015).
4. Super Soft All-Ethylene Oxide Polymer Electrolyte for Safe All-Solid Lithium Batteries. Scientific Reports (2016).
5. Decoupling of mechanical properties and ionic conductivity in supramolecular lithium ion conductors. Nature Communications (2019).
6. Ionic Conduction in Polymer‐Based Solid Electrolytes. Advanced Science (2023).