Adil Md, Sarkar Ananta, Roy Amlan, Panda Manas Ranjan, Nagendra Abharana, Mitra Sagar
Electrochemical Energy Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
IITB-Monash Research Academy, Mumbai 400076, India.
ACS Appl Mater Interfaces. 2020 Mar 11;12(10):11489-11503. doi: 10.1021/acsami.9b20129. Epub 2020 Feb 28.
There is a pressing need for high-rate cycling and cost-effective stationary energy storage systems in concomitance with the fast development of solar, wind, and other types of renewable sources of energy. Aqueous rechargeable Ca-ion batteries have the potential to meet the growing demands of stationary energy storage devices because they are abundant and safe; they can also be manufactured at a low-cost and have a higher volumetric capacity. In this study, we have demonstrated a low-cost, safe, aqueous Ca-ion battery that is based on a low potential, lower specific weight, polymerized polyaniline as an anode, and a high redox-potential open-framework structured potassium copper hexacyanoferrate as a cathode. The charge-discharge mechanism of this battery includes doping/dedoping of NO at the anode, and intercalation and deintercalation of Ca-ion at the cathode. This Ca-ion battery works successfully in a 2.5 M Ca(NO) aqueous electrolyte that exhibits 70 Wh kg specific energy at 250 W kg and even maintains a high energy density of 53 Wh kg at a higher rate of 950 W kg; this indicates a good rate capability (calculation based on anode active mass). At 0.8 A g, the battery provides an average specific capacity of 130 mA h g, exhibiting high Coulombic efficiency (∼96%), with 95% capacity retention of over 200 cycles across its life span, which is a new achievement in the electrochemical performance of aqueous Ca-ion batteries. Furthermore, the calcium-ion storage mechanism is investigated using high-end X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) measurements. Thus, this significant electrochemical performance of the anode and the cathode renders the battery a promising candidate in grid-scale storage applications.
随着太阳能、风能和其他类型可再生能源的快速发展，对高倍率循环和具有成本效益的固定式储能系统有着迫切需求。水系可充电钙离子电池有潜力满足固定式储能设备不断增长的需求，因为它们储量丰富且安全；还能低成本制造且具有较高的体积容量。在本研究中，我们展示了一种低成本、安全的水系钙离子电池，该电池基于低电位、低比重的聚合聚苯胺作为阳极，以及高氧化还原电位的开放框架结构的六氰合铁酸钾铜作为阴极。这种电池的充放电机制包括阳极处NO的掺杂/脱掺杂，以及阴极处钙离子的嵌入和脱嵌。这种钙离子电池在2.5M Ca(NO)水系电解质中成功运行，在250W/kg时表现出70Wh/kg的比能量，甚至在950W/kg的更高倍率下仍保持53Wh/kg的高能量密度；这表明其具有良好的倍率性能（基于阳极活性质量计算）。在0.8A/g时，该电池提供130mAh/g的平均比容量，展现出高库仑效率（约96%），在其整个寿命周期内200多次循环中容量保持率达95%，这是水系钙离子电池电化学性能方面的一项新成就。此外，利用高端X射线吸收近边结构（XANES）和扩展X射线吸收精细结构（EXAFS）测量研究了钙离子存储机制。因此，阳极和阴极的这种显著电化学性能使该电池成为电网规模储能应用中有前景的候选者。
