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

Abstract

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 −1 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 −1 at 20 mA cm −2 ) 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 Li 6 PS 5 Cl. 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.

Dual-ion conductors: from liquid to solid

“…9 In our recent work, we constructed a Li + /Cu + dual-ion conductor based on solid electrolytes for the first time. 26 The universal anion framework of the dual-ion conductor enables the rapid transport of Li + and Cu + , which is the critical foundation for a dual-ion conductor. Thanks to the ionhopping transport mechanism of solid electrolytes, 9 dual-ion conductors can restrict the range of ion transport, and thus dual-ion conductors can prevent the ion crossover between the cathode and anode materials.…”

“…In our previous work, we successfully constructed a dual-ion conductor based on Li + and Cu + , leveraging the close proximity of their ionic radii as a fundamental factor. 26 Additionally, the electronegativity of the elements may be a crucial factor affecting ion transport. Cations not only experience the influence of coulombic forces within the electrolyte framework, but also undergo bonding interactions between ions.…”

“…Secondly, dual-ion conductors can also enhance the interfacial compatibility between the cathode active materials and electrolytes, improving ion transport at the interface and thereby significantly enhancing the kinetic performance of all-solid-state batteries (ASSBs). 26 In our previous work, we constructed a dual-ion conductor to create an ion highway connecting the active material Cu 2 S with the electrolyte (Fig. 5b), increasing the number of mobile charge carriers and significantly enhancing the kinetic performance of all-solid-state batteries.…”

“…Thirdly, dual-ion conductors can activate additional redox reactions in some cathode active materials by facilitating the migration of transition metal ions, thereby significantly increasing the discharge specific capacity and energy density of all-solid-state batteries. 26 In traditional single-ion electrolytes, the Cu 2 S cathode can only achieve the redox reaction of Cu + /Cu through the transport of lithium ions, resulting in limited discharge capacity. However, we successfully activated the valence change of S in the Cu 2 S cathode using a dual-ion conductor (Fig.…”