Electric charge helped guide lithium ions through a solid polymer electrolyte in laboratory battery tests, researchers report in a peer-reviewed Nature Communications paper published September 24. One lithium-metal/lithium iron phosphate coin cell completed nearly 5,000 cycles at 5C, a rate equivalent by nominal capacity to a full charge or discharge in 12 minutes. The −40°C result came from a separate cell.
The design targets a weakness in solid polymer electrolytes: too little of the ionic current is carried by lithium ions rather than their negatively charged counterions. The researchers anchor those anions along a one-dimensional, electrically charged interface in the polymer, drawing lithium ions into that same pathway. They say the resulting crowding makes nearby lithium ions repel one another, loosening the local polymer layer that normally surrounds them and letting the ions move together. The paper calls this arrangement a “Li⁺ shuttle bus.”
The electrolyte's ionic conductivity—a measure of how readily ions carry current through a material—was 0.92 millisiemens per centimetre at 28°C. In the lithium-metal/lithium iron phosphate coin-cell test, the supplement lists 1.5 milligrams of cathode material per square centimetre and 2 microlitres of electrolyte. A different coin cell retained 77% of its starting capacity after 900 cycles at −40°C; that test used a current density of 0.052 milliamps per square centimetre.
A separate lithium-metal pouch cell using a nickel-rich NCM811 cathode was reported at 508 watt-hours per kilogram, with 95.2% capacity retention after 200 cycles. The supplementary table gives a 2.04-amp-hour capacity, 25.2 milligrams per square centimetre of cathode loading and a total cell mass of 16.47 grams; at 28°C, it was charged at 0.1C and discharged at 0.3C—one-tenth and three-tenths of nominal capacity per hour. The test also used 0.5007 grams of carbonate liquid electrolyte to wet the interface, so this was not a liquid-free cell or a battery-pack measurement.
The work offers a specific way to organize ion movement, but it does not show one large-format battery combining the high-rate, cold-temperature and pouch-cell results. Repeating the tests at practical electrode loadings and charging rates in larger cells is the next step toward judging whether the approach can scale.
Sources
- Chen et al., “Li⁺ Shuttle bus enables safe fast ion transport in solid polymer electrolytes,” Nature Communications, published September 24, 2026. Research paper and abstract.
- Official supplementary information (cell loading, current density, cycling conditions and pouch-cell mass).
- Illustrative cell-format diagram by CRBAman, Wikimedia Commons, CC BY-SA 4.0; not the study’s tested cells.