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Copper sulfate as additive for Fe 3 O 4 electrodes of rechargeable Ni–Fe batteries
Author(s) -
Li Xiaofeng,
Dong Huichao,
Song Yanhua,
Zhang Linsen,
Wang Shuai
Publication year - 2020
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.2475
Subject(s) - electrode , copper , analytical chemistry (journal) , scanning electron microscope , cyclic voltammetry , current density , metal , materials science , sulfate , power density , chemistry , metallurgy , electrochemistry , composite material , chromatography , power (physics) , physics , quantum mechanics
CuSO 4 ·5H 2 O was used as an additive for paste Fe 3 O 4 electrode by a simple physical mixing method. The results of cyclic voltammetry and energy dispersive spectroscopy tests confirm that during the initial charge, copper sulfate could be converted to metallic Cu with uniform distribution in the electrode and stable during normal charge–discharge cycles. Compared with the electrode without the additive, the discharge capacity of the one with 5‐wt% CuSO 4 ·5H 2 O increases from 483 to 513 mAh·g −1 at a current density of 90 mAh·g −1 and from 147 to 221 mAh·g −1 at a current density of 900 mAh·g −1 , respectively. After 50 cycles at a current density of 225 mAh·g −1 , its capacity retention rate is 85.7%, but it is only 42.4% for the electrode without the additive. Combined with the results of powder X‐ray diffraction and scanning electron microscopy tests, the improvement in high‐power and cycle performance of the Fe 3 O 4 electrodes might be due to the obvious depassivation caused by metallic Cu.