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A Dual Plating Battery with the Iodine/[ZnI x (OH 2 ) 4− x ] 2− x Cathode
Author(s) -
Hong Jessica J.,
Zhu Liangdong,
Chen Cheng,
Tang Longteng,
Jiang Heng,
Jin Bei,
Gallagher Trenton C.,
Guo Qiubo,
Fang Chong,
Ji Xiulei
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201909324
Subject(s) - cathode , electrolyte , iodide , plating (geology) , electrode , chemistry , inorganic chemistry , iodine , analytical chemistry (journal) , materials science , organic chemistry , geophysics , geology
Plating battery electrodes typically deliver higher specific capacity values than insertion or conversion electrodes because the ion charge carriers represent the sole electrode active mass, and a host electrode is unnecessary. However, reversible plating electrodes are rare for electronically insulating nonmetals. Now, a highly reversible iodine plating cathode is presented that operates on the redox couples of I 2 /[ZnI x (OH 2 ) 4− x ] 2− x in a water‐in‐salt electrolyte. The iodine plating cathode with the theoretical capacity of 211 mAh g −1 plates on carbon fiber paper as the current collector, delivering a large areal capacity of 4 mAh cm −2 . Tunable femtosecond stimulated Raman spectroscopy coupled with DFT calculations elucidate a series of [ZnI x (OH 2 ) 4− x ] 2− x superhalide ions serving as iodide vehicles in the electrolyte, which eliminates most free iodide ions, thus preventing the consequent dissolution of the cathode‐plated iodine as triiodides.