Interfaces Between Cathode and Electrolyte in Solid State Lithium Batteries: Challenges and Perspectives

Abstract

Solid state lithium batteries are widely accepted as promising candidates for next generation of various energy storage devices with the probability to realize improved energy density and superior safety performances. However, the interface between electrode and solid electrolyte remain a key issue that hinders practical development of solid state lithium batteries. In this review, we specifically focus on the interface between solid electrolytes and prevailing cathodes. The basic principles of interface layer formation are summarized and three kinds of interface layers can be categorized. For typical solid state lithium batteries, a most common and daunting challenge is to achieve and sustain intimate solid-solid contact. Meanwhile, different specific issues occur on various types of solid electrolytes, depending on the intrinsic properties of adjacent solid components. Our discussion mostly involves following electrolytes, including solid polymer electrolyte, inorganic solid oxide and sulfide electrolytes as well as composite electrolytes. The effective strategies to overcome the interface instabilities are also summarized. In order to clarify interfacial behaviors fundamentally, advanced characterization techniques with time, and atomic-scale resolution are required to gain more insights from different perspectives. And recent progresses achieved from advanced characterization are also reviewed here. We highlight that the cooperative characterization of diverse advanced characterization techniques is necessary to gain the final clarification of interface behavior, and stress that the combination of diverse interfacial modification strategies is required to build up decent cathode-electrolyte interface for superior solid state lithium batteries.

Intermolecular Chemistry in Solid Polymer Electrolytes for High‐Energy‐Density Lithium Batteries

“…The high‐voltage compatibility represents the capability of electrolyte to restrain oxidative decomposition. Thermodynamically, as shown in Figure , a high‐voltage‐stable SPE means all the components of polymer electrolyte (polymer, lithium salts, and additives) must simultaneously have lower energy level of highest occupied molecular orbital (HOMO) than cathode potential ( µ c ) . However, due to the strong and complicated oxidation state of the cathode materials during lithium deintercalation process, µ c could shift down to the lower state than the HOMO of SPEs, resulting an interfacial parasitic reaction.…”

Sulfide and Oxide Inorganic Solid Electrolytes for All-Solid-State Li Batteries: A Review

“…For example, Famprikis et al [51] and Zhang et al [116] reported on the fundamentals of electrolytes and Oudenhoven et al [117], Julien and Mauger [60], and Rambabu et al [118] reviewed the technology of solid-state microbatteries. Moreover, in situ and ex situ techniques were explored for elucidating the solid electrode/electrolyte interfaces [40,67,80,98,[119][120][121][122][123] and computational methods were reviewed by Xiao et al [94] for understanding the conduction mechanisms in both oxide and sulfide electrolytes.…”

Emerging Role of Non-crystalline Electrolytes in Solid-State Battery Research

“…Presently, the materials research community is wholly engaged in enabling the necessary radical departure(s) from conventional SIB technology. The replacement of the ubiquitous liquid electrolyte in commercial SIB with a solid-state electrolyte (SSE), the new battery configuration being termed an "all-solidstate battery" (ASSB), represents one such paradigmatic shift in energy storage technology (Nie et al, 2018).…”