Chando Paul Alexis, Chen Sihe, Shellhamer Jacob Matthew, Wall Elizabeth, Wang Xinlu, Schuarca Robson, Smeu Manuel, Hosein Ian Dean
Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States.
Department of Physics, Binghamton University State University of New York, Binghamton, New York 13902, United States.
Chem Mater. 2023 Oct 6;35(20):8371-8381. doi: 10.1021/acs.chemmater.3c00659. eCollection 2023 Oct 24.
The dependence on lithium for the energy needs of the world, coupled with its scarcity, has prompted the exploration of postlithium alternatives. Calcium-ion batteries are one such possible alternative owing to their high energy density, similar reduction potential, and naturally higher abundance. A critical gap in calcium-ion batteries is the lack of suitable cathodes for intercalating calcium at high voltages and capacities while also maintaining structural stability. Transition metal oxide postspinels have been identified as having crystal structures that can provide low migration barriers, high voltages, and facile transport pathways for calcium ions and thus can serve as cathodes for calcium-ion batteries. However, experimental validation of transition metal oxide postspinel compounds for calcium ion conduction remains unexplored. In this work, calcium manganese oxide (CaMnO) in the postspinel phase is explored as an intercalation cathode for calcium-ion batteries. CaMnO is first synthesized via solid-state synthesis, and the phase is verified with X-ray diffraction (XRD). The redox activity of the cathode is investigated with cyclic voltammetry (CV) and galvanostatic (GS) cycling, identifying oxidation potentials at 0.2 and 0.5 V and a broad insertion potential at -1.5 V. CaMnO can cycle at a capacity of 52 mAh/g at a rate of C/33, and calcium cycling is verified with energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) and modeled with density functional theory (DFT) simulations. The results from the investigation concluded that CaMnO is a promising cathode for calcium-ion batteries.
世界对锂的能源需求依赖及其稀缺性，促使人们探索后锂时代的替代方案。钙离子电池因其高能量密度、相似的还原电位以及天然更高的丰度，是一种可能的替代方案。钙离子电池的一个关键差距在于缺乏合适的阴极，无法在高电压和高容量下嵌入钙，同时保持结构稳定性。过渡金属氧化物后尖晶石已被确定具有能够提供低迁移势垒、高电压以及钙离子便捷传输路径的晶体结构，因此可作为钙离子电池的阴极。然而，过渡金属氧化物后尖晶石化合物用于钙离子传导的实验验证仍未得到探索。在这项工作中，探索了后尖晶石相的钙锰氧化物（CaMnO）作为钙离子电池的嵌入阴极。首先通过固态合成法合成CaMnO，并通过X射线衍射（XRD）对其相进行验证。用循环伏安法（CV）和恒电流（GS）循环研究阴极的氧化还原活性，确定氧化电位为0.2和0.5 V，以及在-1.5 V处有一个较宽的嵌入电位。CaMnO在C/33的倍率下能够以52 mAh/g的容量循环，通过能量色散X射线光谱（EDS）和X射线光电子能谱（XPS）验证了钙的循环，并利用密度泛函理论（DFT）模拟进行建模。研究结果表明，CaMnO是一种有前景的钙离子电池阴极材料。
