Grafting of Lithiophilic and Electron‐Blocking Interlayer for Garnet‐Based Solid‐State Li Metal Batteries via One‐Step Anhydrous Poly‐Phosphoric Acid Post‐Treatment. (21st December 2022)

• Record Type: Journal Article
• Authors: Guo, Chang; Shen, Yu; Mao, Peng; Liao, Kaiming; Du, Mingjie; Ran, Ran; Zhou, Wei; Shao, Zongping
• Is Part Of: Advanced functional materials. Volume 33:Number 10(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-21
• Subjects: electron blockage -- garnet electrolytes -- li deposition -- polyphosphoric acid -- post‐treatments; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202213443
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Garnet‐based solid‐state Li‐metal batteries (GSSBs) have the merits of high energy density and high safety. However, the realization of a stable and well‐matched Li|garnet interface for GSSBs remains challenging due to electron leakage and lithiophobic Li2 CO3 impurity. To address these issues, herein, new surface chemistry is reported that converts the undesired Li2 CO3 contaminant into an ultra‐thin lithium polyphosphate (Li‐PPA) layer through anhydrous polyphosphoric acid ‐induced in situ substitution reaction without damaging the water‐sensitive garnet electrolyte. In particular, the Li‐PPA interlayer not only facilitates the homogenous spreading of molten Li but also creates a robust electron‐blocking shield to suppress Li dendrite formation. As a result, the assembled Li symmetric cell exhibits a low interfacial impedance (4 Ω cm 2 ) and high critical current density (1.8 mA cm −2 ) at 25 °C, which enables the cell to continuously cycle over 2500 h at 0.2 mA cm −2 . Furthermore, the GSSBs paired with LiFePO4 deliver a high capacity of 149.3 mAh g −1 at 1 C and maintain 92.3% of the initial capacity after 500 cycles and can be used for solar energy storage, suggesting the feasibility of this interfacial engineering strategy for GSSBs. Abstract : Anhydrous polyphosphoric acid is proposed as an enabler for creating an intimate Li | garnet interface with electron‐blocking characteristics, resulting in ultralow interfacial impedance, a fast charge–discharge rate, and remarkable long durability of all‐solid‐state Li metal symmetric and full cells.