Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180.
Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180.
Proc Natl Acad Sci U S A. 2022 Jul 26;119(30):e2205762119. doi: 10.1073/pnas.2205762119. Epub 2022 Jul 21.
Looming concerns regarding scarcity, high prices, and safety threaten the long-term use of lithium in energy storage devices. Calcium has been explored in batteries because of its abundance and low cost, but the larger size and higher charge density of calcium ions relative to lithium impairs diffusion kinetics and cyclic stability. In this work, an aqueous calcium-ion battery is demonstrated using orthorhombic, trigonal, and tetragonal polymorphs of molybdenum vanadium oxide (MoVO) as a host for calcium ions. Orthorhombic and trigonal MoVOs outperform the tetragonal structure because large hexagonal and heptagonal tunnels are ubiquitous in such crystals, providing facile pathways for calcium-ion diffusion. For trigonal MoVO, a specific capacity of ∼203 mAh g was obtained at 0.2C and at a 100 times faster rate of 20C, an ∼60 mAh g capacity was achieved. The open-tunnel trigonal and orthorhombic polymorphs also promoted cyclic stability and reversibility. A review of the literature indicates that MoVO provides one of the best performances reported to date for the storage of calcium ions.
锂在储能设备中应用的长期可持续性面临资源稀缺、价格高昂和安全性等问题的威胁。钙由于其丰富的储量和低廉的成本，被广泛探索应用于电池领域。然而，钙离子的尺寸较大且电荷密度较高，这会影响扩散动力学和循环稳定性。在这项工作中，使用正交、三角和四方多晶型的钼钒氧化物 (MoVO) 作为钙离子的宿主，展示了一种水系钙离子电池。正交和三角 MoVOs 的性能优于四方结构，因为在这些晶体中普遍存在大的六角形和七角形隧道，为钙离子扩散提供了便捷的通道。对于三角 MoVO，在 0.2C 时获得了约 203 mAh g 的比容量，在 20C 的 100 倍快速率下，获得了约 60 mAh g 的容量。开放隧道的三角和正交多晶型也促进了循环稳定性和可逆性。对文献的综述表明，MoVO 是目前报道的用于存储钙离子的性能最佳的材料之一。
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