Gómez-Berenguer Irene, Herradón Bernardo, Amarilla José Manuel, Castillo-Martínez Elizabeth
Departamento de Química Inorgánica, Universidad Complutense de Madrid, 28040 Madrid, Spain.
Instituto de Química Orgánica General, Consejo Superior de Investigaciones Científicas, 28006 Madrid, Spain.
Materials (Basel). 2024 Oct 8;17(19):4918. doi: 10.3390/ma17194918.
Bismine sodium salt (BSNa), a Schiff base with two sodium carboxylates, has shown promising electrochemical performance as an anode material. However, its synthesis involves toxic reagents and generates impurities, requiring significant solvent use for purification. This study introduces a novel synthetic method using sodium hydroxide as the sole reagent, which acts as both a base and Na source in the ion exchange step. With this procedure, we reduce the amounts of chemicals, diminish toxicity, improve the purity of the target compound, and use less solvent while maintaining comparable electrochemical performance. Additionally, the procedure is carried out under anhydrous conditions that avoid the undesirable hydrolysis of the imine linkages. In a previous report, the processing of the composite electrode was not established. In this article, we address this issue; the electrochemical performance, specifically the rate capability, is enhanced by processing the electrodes in laminate form rather than powder. As alternative to N-methyl-2-pyrrolidone (NMP), a common but disadvantageous solvent in laminate processing, other solvents were explored by testing acetone (DMK), methylisopropylketone (MIPK), and a DMK-NMP mixture. The remarkable electrochemical performance (specific capacity of 260-280 mAh/g, and capacity retentions higher than 84% at 1C (260 mA/g) remained consistent across these solvents. Furthermore, we investigated replacing copper with aluminum as the current collector to reduce costs and increase the energy density of the battery. While aluminum performed comparably to copper at low specific currents C/10 (26 mA/g), it showed a significant shift in the redox process potentials at higher specific currents.
双胺钠盐（BSNa）是一种含有两个羧酸钠的席夫碱，作为阳极材料已展现出有前景的电化学性能。然而，其合成涉及有毒试剂并会产生杂质，纯化时需要大量溶剂。本研究引入了一种以氢氧化钠作为唯一试剂的新型合成方法，氢氧化钠在离子交换步骤中既作为碱又作为钠源。通过此方法，我们减少了化学试剂用量，降低了毒性，提高了目标化合物的纯度，减少了溶剂使用量，同时保持了相当的电化学性能。此外，该方法在无水条件下进行，避免了亚胺键的不良水解。在之前的一份报告中，复合电极的制备方法尚未确立。在本文中，我们解决了这个问题；通过将电极加工成层压形式而非粉末形式，电化学性能，特别是倍率性能得到了提高。作为层压加工中常用但有缺点的溶剂N - 甲基 - 2 - 吡咯烷酮（NMP）的替代品，我们通过测试丙酮（DMK）、甲基异丙基酮（MIPK）以及DMK - NMP混合物探索了其他溶剂。在这些溶剂中，显著的电化学性能（比容量为260 - 280 mAh/g，在1C（260 mA/g）下容量保持率高于84%）保持一致。此外，我们研究了用铝替代铜作为集流体以降低成本并提高电池的能量密度。虽然在低比电流C/10（26 mA/g）下铝的性能与铜相当，但在较高比电流下它在氧化还原过程电位上出现了明显偏移。
