Ultra‐High Initial Coulombic Efficiency Induced by Interface Engineering Enables Rapid, Stable Sodium Storage

• Published in: Angewandte Chemie International Edition 2021-05, Vol.60 (20), p.11481-11486
• Main Authors: Wan, Yanhua, Song, Keming, Chen, Weihua, Qin, Changdong, Zhang, Xixue, Zhang, Jiyu, Dai, Hongliu, Hu, Zhe, Yan, Pengfei, Liu, Chuntai, Sun, Shuhui, Chou, Shu‐Lei, Shen, Changyu
• Format: Article
• Language: English
• Subjects: Batteries; Catalysis; Construction; defect repair; Defects; Diethylene glycol; Dimethyl ether; Efficiency; Electrolytes; initial coulombic efficiency; interface catalysis; Interphase; Iron sulfides; Nanoclusters; Power consumption; Pyrite; Sodium; sodium-ion batteries; solid electrolyte interphase; Solid electrolytes
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202102368

High initial coulombic efficiency is highly desired because it implies effective interface construction and few electrolyte consumption, indicating enhanced batteries’ life and power output. In this work, a high‐capacity sodium storage material with FeS2 nanoclusters (≈1–2 nm) embedded in N, S‐doped carbon matrix (FeS2/N,S‐C) was synthesized, the surface of which displays defects‐repaired characteristic and detectable dot‐matrix distributed Fe‐N‐C/Fe‐S‐C bonds. After the initial discharging process, the uniform ultra‐thin NaF‐rich (≈6.0 nm) solid electrolyte interphase was obtained, thereby achieving verifiable ultra‐high initial coulombic efficiency (≈92 %). The defects‐repaired surface provides perfect platform, and the catalysis of dot‐matrix distributed Fe‐N‐C/Fe‐S‐C bonds to the rapid decomposing of NaSO3CF3 and diethylene glycol dimethyl ether successfully accelerate the building of two‐dimensional ultra‐thin solid electrolyte interphase. DFT calculations further confirmed the catalysis mechanism. As a result, the constructed FeS2/N,S‐C provides high reversible capacity (749.6 mAh g−1 at 0.1 A g−1) and outstanding cycle stability (92.7 %, 10 000 cycles, 10.0 A g−1). Especially, at −15 °C, it also obtains a reversible capacity of 211.7 mAh g−1 at 10.0 A g−1. Assembled pouch‐type cell performs potential application. The insight in this work provides a bright way to interface design for performance improvement in batteries. A defect‐repairing‐induced dot–matrix distributed interface efficiently catalyzes electrolyte decomposition. This strategy enables an ultra‐thin and robust solid–electrolyte interface achieving ultra‐high initial coulombic efficiency in sodium‐ion batteries.