Argyrodite-type advanced lithium conductors and transport mechanisms beyond peddle-wheel effect

Development of next-generation solid-state Li-ion batteries requires not only electrolytes with high room-temperature (RT) ionic conductivities but also a fundamental understanding of the ionic transport in solids. In spite of considerable work, only a few lithium conductors are known with the highest RT ionic conductivities similar to 0.01 S/cm and the lowest activation energies similar to 0.2 eV. New design strategy and novel ionic conduction mechanism are needed to expand the pool of high-performance lithium conductors as well as achieve even higher RT ionic conductivities. Here, we theoretically show that lithium conductors with RT ionic conductivity over 0.1 S/cm and low activation energies similar to 0.1 eV can be achieved by incorporating cluster-dynamics into an argyrodite structure. The extraordinary superionic metrics are supported by conduction mechanism characterized as a relay between local and long-range ionic diffusions, as well as correlational dynamics beyond the paddle-wheel effect.

Automated summary

Developing high-performance solid-state lithium-ion batteries requires electrolytes with high room-temperature ionic conductivities, new design strategies, and ionic conduction mechanisms. Incorporating cluster-dynamics into an argyrodite structure can achieve higher room-temperature ionic conductivity and lower activation energies.