Anion Solvation Reconfiguration Enables High‐Voltage Carbonate Electrolytes for Stable Zn/Graphite Cells. Issue 48 (21st September 2020)

• Record Type: Journal Article
• Authors: Chen, Zheng; Tang, Yue; Du, Xiaofan; Chen, Bingbing; Lu, Guoli; Han, Xiaoqi; Zhang, Yaojian; Yang, Wuhai; Han, Pengxian; Zhao, Jingwen; Cui, Guanglei
• Is Part Of: Angewandte Chemie international edition. Volume 59:Issue 48(2020)
• Page Start: 21769
• Page End: 21777
• Publication Date: 2020-09-21
• Subjects: anion solvation -- carbonate electrolytes -- high power density -- micro-heterogeneous distribution -- oxidation stability; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202010423
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Conventional carbonate solvents with low HOMO levels are theoretically compatible with the low‐cost, high‐voltage chemistry of Zn/graphite batteries. However, the nucleophilic attack of the anion on carbonates induces an oxidative breakdown at high potentials. Here, we restore the inherent anodic stability of carbonate electrolytes by designing a micro‐heterogeneous anion solvation network. Based on the addition of a strongly electron‐donating solvent, trimethyl phosphate (TMP), the oxidation‐vulnerable anion‐carbonate affinities are decoupled because of the preferential sequestration of anions into solvating TMP domains around the metal cations. The hybridized electrolytes elevate the electrochemical window of carbonate electrolytes by 0.45 V and enable the operation of Zn/graphite dual‐ion cells at 2.80 V with a long cycle life (92 % capacity retention after 1000 cycles). By inheriting the non‐flammability from TMP and the high ion‐transport kinetics from the carbonate systems, this facile strategy provides cells with the additional benefits of fire retardancy and high‐power capability. Abstract : Through the strategy of anion solvation regulation, a reconfigurated anion solvation network is formed which significantly reduces the oxidative‐vulnerable anion‐carbonate affinities. This leads to an enhanced oxidation stability of carbonate electrolytes which enables highly stable Zn/graphite cells.