A mixing entropy battery (MEB) based on a pair of cationic and anionic electrodes is a novel method to extract salinity gradient (SG) energy. However, so far, only precious AgCl electrodes are reported as anionic electrodes in MEBs. Herein, it is demonstrated that bismuth oxychloride (BiOCl) can be an alternative anionic electrode for MEBs to harvest SG energy. In tests with 30 and 1 g L⁻¹ NaCl solutions, the origin MEB with uncoated BiOCl anionic and copper hexacyanoferrate (CuHCF) cationic electrodes produces an energy density of 8 J m⁻² and an average power density of 59 mW m⁻². To boost the power output, the origin BiOCl and CuHCF electrodes are coated with polyelectrolytes. The energy density (12 J m⁻²) and average power density (87 mW m⁻²) of the coated MEB are nearly 50% higher than those of the origin MEB and are stable over 50 cycles, which is comparable and even higher than those with AgCl anionic electrodes. These results indicate that BiOCl can be a cheap alternative to the AgCl anionic electrode, and polyelectrolyte coatings can be a cheaper alternative to ion‐exchange membranes in MEBs for efficient SG energy recovery.

中文翻译：

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聚电解质包覆的六氰基高铁酸铜和三氧化二铋电极可在电容混合中有效地恢复盐度梯度能量

基于一对阳离子和阴离子电极的混合熵电池（MEB）是一种提取盐度梯度（SG）能量的新方法。然而，到目前为止，在MEB中仅报道了贵重的AgCl电极作为阴离子电极。在本文中，已证明氯氧化铋（BiOCl）可以作为MEB收集SG能量的替代阴离子电极。在使用30 g和1 g L ^-1 NaCl溶液的测试中，未涂覆的BiOCl阴离子和六氰合铁酸铜（CuHCF）阳离子电极的原始MEB产生的能量密度为8 J m ^-2，平均功率密度为59 mW m ^-2。为了提高功率输出，原始BiOCl和CuHCF电极均涂有聚电解质。能量密度（12 J m ^-2）和涂覆的MEB的平均功率密度（87 mW m ^-2）比原始MEB的平均功率密度高近50％，并且在50个循环中保持稳定，这与AgCl阴离子电极相当甚至更高。这些结果表明，BiOCl可以便宜地替代AgCl阴离子电极，而聚电解质涂层可以便宜地替代MEB中的离子交换膜，从而有效地回收SG能量。