Today’s batteries contain flammable, toxic, liquid electrolytes. Therefore, safer all-solid-state batteries are a current research goal. This requires solid-electrolyte materials with high ionic mobilities, high chemical and electrochemical stabilities, and good formability. The status-quo solid-electrolyte materials have various shortcomings. NIST has developed a novel solid superionic conductor material to satisfy the current lack of suitable electrolytes for incorporation into next-generation all-solid-state energy devices.
These materials combine Li+, Na+, or other cations with large polyhedral borate and/or carbaborate anions to form a new class of ionic salt compounds that can exhibit superionic conductivities in their disordered salt phases. Using treatment strategies that involve particle-size reduction and compound mixing, NIST is able to create modified materials that remain in their superionic state at all temperatures. They can be used as fast-ion solid electrolytes in all-solid-state batteries. They possess favorable electrochemical and thermal stability while also displaying relatively high ionic conductivities at technically relevant device temperatures. These new materials could be gamechangers.
The figure below is an exemplary ambient-temperature, superionic solid electrolyte salt formed by the incorporation of either Li+ or Na+ cations (orange spheres) within a hexagonally stacked mixture of orientationally disordered, randomly distributed, polyhedral CB9H10−and CB11H12−anions (large green/gray spheres).
Terrence John Udovic
Materials Physics and Chemistry
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