Solid-State Electrolytes in Lithium Battery Systems

Solid-state electrolytes (SSEs) represent a transformative advance in lithium battery technology, offering the prospect of higher energy density, improved safety and wider operating temperatures compared with conventional liquid electrolytes. By replacing flammable organic solvents with ion-conductive solids, SSEs can enable the use of lithium metal anodes, potentially doubling cell capacity. Key material classes include oxide, sulfide and polymer electrolytes, as well as composites that combine different phases to optimise conductivity and mechanical robustness. Sulfide electrolytes stand out for their room-temperature ionic conductivities approaching those of liquids, but their environmental sensitivity and interfacial instability pose challenges. Oxide ceramics deliver excellent chemical stability yet often require higher pressures to maintain intimate contact with electrodes. Polymer electrolytes provide flexibility and ease of processing but generally need elevated temperatures to achieve acceptable conductivities. Recent efforts focus on interfacial engineering to suppress degradation reactions, nanostructuring to enhance ion pathways and compositional tuning to improve air stability. The integration of glass–ceramic materials and argyrodite frameworks has yielded record conductivities, while novel halogen doping and additive strategies address moisture tolerance. Collectively, these innovations advance the practical realisation of all-solid-state lithium batteries for electric vehicles, portable electronics and grid-scale storage.

Research from Nature Portfolio

Researchers have developed a series of silicon- and tin-substituted arsenic-sulfide electrolytes that deliver exceptional cycling stability when paired with lithium-indium and titanium-sulphide electrodes. These materials sustain tens of thousands of cycles at high current densities, demonstrating the viability of tailored sulfide chemistries for long-life cells. In parallel, systematic variation of chlorine content and cooling protocols in lithium-phosphorus-sulfur-chloride ceramics has been shown to create surface-bound LiCl frameworks, which migrate to form a stabilising interphase and suppress parasitic reactions at the lithium interface. Most recently, investigations into glassy sulfide networks have revealed that increasing interstitial volume enables unprecedented solubility of halogen dopants, producing glass electrolytes with ionic conductivities among the highest recorded for amorphous materials and serving as effective fillers in composite membranes to arrest lithium intrusion.

Research from all publishers

A newly synthesised Bi- and I-co-doped glass-ceramic electrolyte exhibits robust air stability and high ionic conductivity, thanks to strong Bi–S bonds and an in situ LiI interphase that protects lithium metal. This material retains over 95 % capacity in prototype cells after hundreds of cycles. Another study has demonstrated that treating argyrodite Li6PS5Cl particles with Lewis acid additives at the nanoscale markedly enhances moisture tolerance by forming protective surface interactions without compromising conductivity. A distinct approach employs fluorine- and oxygen-rich nanoshells on Li6PS4Cl-based electrolytes, simultaneously improving air stability, electrode compatibility and lithium deposition homogeneity, thereby enabling high-voltage and high-loading operation over extended cycling.

Solid-State Electrolytes in Lithium Battery Systems publication trend

The graph below shows the total number of articles in solid-state electrolytes in lithium battery systems across all publications each year (not limited to Nature Index journals).

Technical terms

Ionic conductivity: the ability of a material to transport charged ions under an electric field, typically expressed in siemens per centimetre.

Interphase: a thin region of modified chemistry and structure that forms between electrode and electrolyte during cell operation.

Argyrodite: a family of sulfide electrolytes characterised by a unique anion framework that facilitates rapid lithium-ion migration.

Glass–ceramic electrolyte: a hybrid solid electrolyte featuring both amorphous glassy regions and crystalline domains to balance conductivity and mechanical strength.

All-solid-state battery: an electrochemical cell in which both the electrolyte and electrodes are solid materials, eliminating liquid components.

Interstitial volume: the free space within a solid matrix that can accommodate dopant atoms or mobile ions, influencing conductivity and solubility.

References

1. Air‐stable Li3.12P0.94Bi0.06S3.91I0.18 solid‐state electrolyte with high ionic conductivity and lithium anode compatibility toward high‐performance all‐solid‐state lithium metal batteries. SusMat (2024).
2. Moisture Robustness of Li6PS5Cl Argyrodite Sulfide Solid Electrolyte Improved by Nano-Level Treatment with Lewis Acid Additives. ACS Energy Letters (2024).
3. Realizing long-cycling all-solid-state Li-In||TiS2 batteries using Li6+xMxAs1-xS5I (M=Si, Sn) sulfide solid electrolytes. Nature Communications (2023).
4. Promoting favorable interfacial properties in lithium-based batteries using chlorine-rich sulfide inorganic solid-state electrolytes. Nature Communications (2022).
5. Deciphering the critical role of interstitial volume in glassy sulfide superionic conductors. Nature Communications (2024).
6. One Stone, Three Birds: An Air and Interface Stable Argyrodite Solid Electrolyte with Multifunctional Nanoshells. Advanced Science (2023).