Valvo Mario, Liivat Anti, Eriksson Henrik, Tai Cheuk-Wai, Edström Kristina
Department of Chemistry-Ångström Laboratory, Uppsala University, Box 538, 75121, Uppsala, Sweden), Fax: (+46) 018-513-548.
Department of Materials and Environmental Chemistry-Arrhenius Laboratory, Stockholm University, 10691, Stockholm, Sweden.
ChemSusChem. 2017 Jun 9;10(11):2431-2448. doi: 10.1002/cssc.201700070. Epub 2017 May 5.
Environmentally friendly and cost-effective Li-ion cells are fabricated with abundant, non-toxic LiFePO cathodes and iron oxide anodes. A water-soluble alginate binder is used to coat both electrodes to reduce the environmental footprint. The critical reactivity of LiPF -based electrolytes toward possible traces of H O in water-processed electrodes is overcome by using a lithium bis(oxalato)borate (LiBOB) salt. The absence of fluorine in the electrolyte and binder is a cornerstone for improved cell chemistry and results in stable battery operation. A dedicated approach to exploit conversion-type anodes more effectively is also disclosed. The issue of large voltage hysteresis upon conversion/de-conversion is circumvented by operating iron oxide in a deeply lithiated Fe/Li O form. Li-ion cells with energy efficiencies of up to 92 % are demonstrated if LiFePO is cycled versus such anodes prepared through a pre-lithiation procedure. These cells show an average energy efficiency of approximately 90.66 % and a mean Coulombic efficiency of approximately 99.65 % over 320 cycles at current densities of 0.1, 0.2 and 0.3 mA cm . They retain nearly 100 % of their initial discharge capacity and provide an unmatched operation potential of approximately 2.85 V for this combination of active materials. No occurrence of Li plating was detected in three-electrode cells at charging rates of approximately 5C. Excellent rate capabilities of up to approximately 30C are achieved thanks to the exploitation of size effects from the small Fe nanoparticles and their reactive boundaries.
采用丰富、无毒的磷酸铁锂阴极和氧化铁阳极制造出了环保且经济高效的锂离子电池。使用水溶性海藻酸盐粘合剂涂覆两个电极，以减少对环境的影响。通过使用双（草酸根）硼酸锂（LiBOB）盐，克服了基于LiPF的电解质对水处理电极中可能存在的微量H₂O的关键反应性。电解质和粘合剂中不含氟是改善电池化学性能的基石，并导致电池运行稳定。还公开了一种更有效地利用转换型阳极的专用方法。通过以深度锂化的Fe/Li₂O形式操作氧化铁，规避了转换/去转换时大电压滞后的问题。如果将磷酸铁锂与通过预锂化程序制备的此类阳极进行循环，则可证明锂离子电池的能量效率高达92%。在0.1、0.2和0.3 mA cm⁻²的电流密度下，这些电池在320次循环中显示出平均能量效率约为90.66%，平均库仑效率约为99.65%。它们保留了近100%的初始放电容量，并为这种活性材料组合提供了约2.85 V的无与伦比的工作电位。在三电极电池中，以约5C的充电速率未检测到锂镀层的出现。由于利用了小铁纳米颗粒的尺寸效应及其反应边界，实现了高达约30C的优异倍率性能。
