Reaction Mechanisms of Ta-Substituted Cubic Li7La3Zr2O12 with Solvents During Storage

Ionic Conductivity and Cycling Performance in PEO Polymer Electrolyte Enhanced by Non-Milled In Situ Nano-LLZO Powders

High Li+ conductivity, good interfacial compatibility, and nano-scale particle size have always been essential conditions for selecting inorganic fillers in high-performance composite solid electrolytes. In this study, non-milled in situ LLZO fillers with nanosize was synthesized via the sol-gel method by rapid heating sintering, which resulted in more surface defects and fewer impurities in LLZO. Compared with milled LLZO fillers, these non-milled LLZO fillers with more surface defects and fewer impurities can effectively reduce the crystallinity of PEO and agglomeration in PEO, which can form composite electrolytes with high Li+ conductivity. Most importantly, the discharge capacity of the 7.5% non-milled LLZO-PEO-based LiFePO4/Li battery is about 135.5 mA h g-1 at 1C and 60 °C. After 100 cycles, the discharge specific capacity remains at 99%. It is worth noting that nano-sized non-milled LLZO will improve the discharge capacity of LiFePO4/Li batteries to 122.1 mA h g-1 at 0.2C and 30 °C.

Processing and Properties of Garnet-Type Li7 La3 Zr2 O12 Ceramic Electrolytes

Garnet-type solid electrolyte Li₇ La₃ Zr₂ O₁₂ (LLZO) is widely considered as one of the most promising candidates for solid state batteries (SSBs) owing to its high ionic conductivity and good electrochemical stability. Since its discovery in 2007, great progress has been made in terms of crystal chemistry, chemical and electrochemical properties, and battery application. Nonetheless, reliable and controllable preparation of LLZO ceramics with desirable properties still remains as big challenges. Herein, this review summarizes various synthetic routes of LLZO ceramics and examines the influence of various key processing parameters on the chemical and electrochemical properties. Focusing on correlation of processing parameters and properties, this review aims to provide new insights on a reliable and controllable production of high-quality LLZO ceramic electrolytes for SSB application.

Tailoring Practically Accessible Polymer/Inorganic Composite Electrolytes for All-Solid-State Lithium Metal Batteries: A Review

Highlights

The current issues and recent advances in polymer/inorganic composite electrolytes are reviewed. The molecular interaction between different components in the composite environment is highlighted for designing high-performance polymer/inorganic composite electrolytes. Inorganic filler properties that affect polymer/inorganic composite electrolyte performance are pointed out. Future research directions for polymer/inorganic composite electrolytes compatible with high-voltage lithium metal batteries are outlined.

Abstract

Solid-state electrolytes (SSEs) are widely considered the essential components for upcoming rechargeable lithium-ion batteries owing to the potential for great safety and energy density. Among them, polymer solid-state electrolytes (PSEs) are competitive candidates for replacing commercial liquid electrolytes due to their flexibility, shape versatility and easy machinability. Despite the rapid development of PSEs, their practical application still faces obstacles including poor ionic conductivity, narrow electrochemical stable window and inferior mechanical strength. Polymer/inorganic composite electrolytes (PIEs) formed by adding ceramic fillers in PSEs merge the benefits of PSEs and inorganic solid-state electrolytes (ISEs), exhibiting appreciable comprehensive properties due to the abundant interfaces with unique characteristics. Some PIEs are highly compatible with high-voltage cathode and lithium metal anode, which offer desirable access to obtaining lithium metal batteries with high energy density. This review elucidates the current issues and recent advances in PIEs. The performance of PIEs was remarkably influenced by the characteristics of the fillers including type, content, morphology, arrangement and surface groups. We focus on the molecular interaction between different components in the composite environment for designing high-performance PIEs. Finally, the obstacles and opportunities for creating high-performance PIEs are outlined. This review aims to provide some theoretical guidance and direction for the development of PIEs.