Zinc-Catalyzed Two-Electron Nickel(IV/II) Redox Couple for Multi-Electron Storage in Redox Flow Batteries
Zinc-Catalyzed Two-Electron Nickel(IV/II) Redox Couple for Multi-Electron Storage in Redox Flow Batteries
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锌催化双电子镍（IV/II）氧化还原对用于氧化还原液流电池中的多电子存储
DOI：
10.1021/acs.inorgchem.2c03124
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发表时间：
2022
影响因子：
4.6
通讯作者：
Farnum, Byron H.
中科院分区：
文献类型：
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作者：
Mazumder, Md. Motiur;Dalpati, Niharika;Pokkuluri, P. Raj;Farnum, Byron H.
储能是在全球范围内成功实施可再生能源的一个重要方面。在此，我们研究了镍（II）双（二乙基二硫代氨基甲酸酯），镍（DTC）2，作为一个多电子存储阴极电解质在非水氧化还原液流电池（RFBs）的潜在用途的氧化还原循环。已有的研究表明，NiII（dtc）2独特的氧化还原循环是由NiII→ NiIV氧化为2 e-化学，由NiIV→ NiIII→ NiII还原为1 e-化学。电化学实验表明，在电解液中加入10 mol %的ZnII（ClO 4）2可将两个1 e还原峰合并为单一的2 e还原峰，其中[NiIV（dtc）3]+直接还原为NiII（dtc）2。这种催化增强被认为是由于ZnII去除的DTC-配体从NiIII（dtc）3中间体，导致更容易还原为NiII（dtc）2。此外，Zn Ⅱ也改善了2 e-氧化，移动阳极峰负，减少2 e-峰分离。氢电池循环实验表明，以0.1M ZnII（ClO 4）2为支持电解质，50次循环25 h后，库仑效率和电荷储存效率分别保持在97%和98%。用TBAPF 6代替ZnII（ClO 4）2后，库仑效率下降到78%。使用ZnII来增加2 e-转移的可逆性是一个有希望的结果，其指出使用二硫代碳酸镍用于RFBs中的多电子存储的能力。
Energy storage is a vital aspect for the successful implementation of renewable energy resources on a global scale. Herein, we investigated the redox cycle of nickel(II) bis(diethyldithiocarbamate), NiII(dtc)2, for potential use as a multielectron storage catholyte in nonaqueous redox flow batteries (RFBs). Previous studies have shown that the unique redox cycle of NiII(dtc)2offers 2e–chemistry upon oxidation from NiII→ NiIVbut 1e–chemistry upon reduction from NiIV→ NiIII→ NiII. Electrochemical experiments presented here show that the addition of as little as 10 mol % ZnII(ClO4)2to the electrolyte consolidates the two 1e–reduction peaks into a single 2e–reduction where [NiIV(dtc)3]+is reduced directly to NiII(dtc)2. This catalytic enhancement is believed to be due to ZnIIremoval of a dtc–ligand from a NiIII(dtc)3intermediate, resulting in more facile reduction to NiII(dtc)2. The addition of ZnIIalso improves the 2e–oxidation, shifting the anodic peak negative and decreasing the 2e–peak separation. H-cell cycling experiments showed that 97% Coulombic efficiency and 98% charge storage efficiency was maintained for 50 cycles over 25 h using 0.1 M ZnII(ClO4)2as the supporting electrolyte. If ZnII(ClO4)2was replaced with TBAPF6in the electrolyte, the Coulombic efficiency fell to 78%. The use of ZnIIto increase the reversibility of 2e–transfer is a promising result that points to the ability to use nickel dithiocarbonates for multielectron storage in RFBs.