Wang Da, Gao Xiangwen, Chen Yuhui, Jin Liyu, Kuss Christian, Bruce Peter G
Nat Mater. 2018 Jan;17(1):16-20. doi: 10.1038/nmat5036. Epub 2017 Nov 27.
There is considerable interest in multivalent cation batteries, such as those based on magnesium, calcium or aluminium. Most attention has focused on magnesium. In all cases the metal anode represents a significant challenge. Recent work has shown that calcium can be plated and stripped, but only at elevated temperatures, 75 to 100 °C, with small capacities, typically 0.165 mAh cm, and accompanied by significant side reactions. Here we demonstrate that calcium can be plated and stripped at room temperature with capacities of 1 mAh cm at a rate of 1 mA cm, with low polarization (∼100 mV) and in excess of 50 cycles. The dominant product is calcium, accompanied by a small amount of CaH that forms by reaction between the deposited calcium and the electrolyte, Ca(BH) in tetrahydrofuran (THF). This occurs in preference to the reactions which take place in most electrolyte solutions forming CaCO, Ca(OH) and calcium alkoxides, and normally terminate the electrochemistry. The CaH protects the calcium metal at open circuit. Although this work does not solve all the problems of calcium as an anode in calcium-ion batteries, it does demonstrate that significant quantities of calcium can be plated and stripped at room temperature with low polarization.
人们对多价阳离子电池，比如基于镁、钙或铝的电池，有着浓厚的兴趣。大部分关注都集中在镁电池上。在所有情况下，金属阳极都是一个重大挑战。最近的研究表明，钙可以进行电镀和脱镀，但只能在75至100°C的高温下进行，且容量较小，通常为0.165 mAh cm，同时还伴随着明显的副反应。在此，我们证明钙可以在室温下以1 mA cm的电流密度、1 mAh cm的容量进行电镀和脱镀，极化程度低（约100 mV），且循环次数超过50次。主要产物是钙，同时会生成少量的CaH，它是由沉积的钙与四氢呋喃（THF）中的电解质Ca(BH)反应形成的。这种情况优先于在大多数电解质溶液中发生的生成CaCO、Ca(OH)和钙醇盐的反应，而这些反应通常会终止电化学过程。CaH在开路时保护钙金属。尽管这项工作并没有解决钙作为钙离子电池阳极的所有问题，但它确实证明了在室温下可以以低极化程度大量地进行钙的电镀和脱镀。
