Heteroatom-based doping and neutron diffraction: doping strategies and mechanisms for ionic conductivity enhancement in inorganic solid-state electrolytes

Abstract

Inorganic solid-state electrolytes (ISEs) are ceramic materials with high ionic transport for lithium ions, which can provide a stable and efficient transport medium for ion flow between positive and negative electrodes. High ionic conductivity is their core issue in all-solid-state batteries, and structural stability is crucial for their performance. Studies have shown that the doping strategy is an effective method to improve the performance of such electrolytes. This paper systematically summarizes the research progress on heteroatom doping in ISEs in recent years. Firstly, the effect of doping on ISEs is introduced, focusing on the mechanism of different elemental doping strategies to improve the performance of ISEs from two perspectives, namely, isovalent elemental doping and heterovalent elemental doping. Their applications in sulphide, oxide and halide solid electrolytes are summarized separately. In addition, the progress of neutron diffraction techniques in analyzing the structure of doped solid electrolytes and revealing the mechanism of ion transport enhancement is comprehensively summarized. Finally, an outlook is given on how to rationally design doping strategies to enhance the performance of solid electrolytes and the potential application of neutron characterization techniques to reveal the doping ISE mechanism.