Recent Advancements in Li-Ion Conductors for All-Solid-State Li-Ion Batteries

TLDR

Inorganic solid lithium‑ion conductors are promising safety alternatives to conventional organic electrolytes, but achieving liquid‑electrolyte‑level conductivities (>1 mS cm⁻¹) remains a challenge. The study discusses strategies to enhance ionic conductivity, including theoretical approaches, to optimize the electrolyte/electrode interface and improve cell performance. The authors review doping strategies and theoretical approaches to enhance conductivity, and describe the structure and conductivity of crystalline Li‑ion conductors such as NASICON, garnet, perovskite, and LISICON types.

Abstract

Inorganic solid lithium ion conductors are potential candidates as replacement for conventional organic electrolytes for safety concerns. However, achieving a Li-ion conductivity comparable to that in existing liquid electrolytes (>1 mS cm–1) remains a challenge in solid-state electrolytes. One of the approaches for achieving a desirable conductivity is doping of various elements into the lattice framework. Our discussion on the structure and conductivity of crystalline Li-ion conductors includes description of NAtrium Super Ionic CONductor (NASICON)-type conductors, garnet-type conductors, perovskite-type conductors, and Lithium Super Ionic CONductor (LISICON)-type conductors. Moreover, we discuss various strategies currently used to enhance ionic conductivity, including theoretical approaches, ultimately optimizing the electrolyte/electrode interface and improving cell performance.