A prototype of dual-ion conductor for all-solid-state lithium batteries.

All-solid-state batteries (ASSBs) represent a promising battery strategy to achieve high energy density with great safety. However, inadequate kinetic property and poor interfacial compatibility remain great challenges, which impede their practical application. A prototype of dual-ion conductor of Li synchronized with Cu unlocks a four-electron redox reaction with high reversibility and fast kinetics. As a result, the constructed ASSB exhibited a high reversible capacity of 603.0 mA·hour g and an excellent cycling retention of 93.2% over 1500 cycles. Moreover, because of the ion highway connecting active materials and catholytes constructed by dual-ion conductor, remarkable temperature tolerance (-60°C) and excellent rate performance (231.6 mA·hour g at 20 mA cm) were achieved. The superior electrochemical performance can be ascribed to the migration pathway with small energy barrier and low tortuosity once the Cu introduced into LiPSCl. This work creates a unique perspective of ASSBs with dual-ion conducting strategy, thus inspiring a potential developing strategy of state-of-the-art ASSBs.