Functional Thin Films Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen, China.
Nat Chem. 2018 Jun;10(6):667-672. doi: 10.1038/s41557-018-0045-4. Epub 2018 Apr 23.
Calcium-ion batteries (CIBs) are attractive candidates for energy storage because Ca has low polarization and a reduction potential (-2.87 V versus standard hydrogen electrode, SHE) close to that of Li (-3.04 V versus SHE), promising a wide voltage window for a full battery. However, their development is limited by difficulties such as the lack of proper cathode/anode materials for reversible Ca intercalation/de-intercalation, low working voltages (<2 V), low cycling stability, and especially poor room-temperature performance. Here, we report a CIB that can work stably at room temperature in a new cell configuration using graphite as the cathode and tin foils as the anode as well as the current collector. This CIB operates on a highly reversible electrochemical reaction that combines hexafluorophosphate intercalation/de-intercalation at the cathode and a Ca-involved alloying/de-alloying reaction at the anode. An optimized CIB exhibits a working voltage of up to 4.45 V with capacity retention of 95% after 350 cycles.
钙离子电池（CIBs）作为储能候选物极具吸引力，因为钙的极化率低，还原电位（相对于标准氢电极，-2.87 V）接近锂的还原电位（-3.04 V），有望实现更宽的电池工作电压窗口。然而，其发展受到诸多因素的限制，如缺乏可逆的 Ca 嵌入/脱嵌用合适的阴极/阳极材料、工作电压低（<2 V）、循环稳定性差，尤其是在室温下的性能较差。在此，我们报道了一种在新的电池构型中，使用石墨作为阴极、锡箔作为阳极和集流体的 CIB，该电池在室温下可稳定工作。这种 CIB 基于正极的六氟磷酸盐嵌入/脱嵌和负极的 Ca 参与的合金化/脱合金化反应，实现了高度可逆的电化学反应。优化后的 CIB 具有高达 4.45 V 的工作电压，经过 350 次循环后容量保持率为 95%。
