Sodium-ion batteries (SIBs) are among the plethora of energy storage devices (ESDs) developed by researchers in the lithium-ion battery (LIB) era of the modern electronic world. Regardless of whether SIBs can replace LIBs or not in the electric vehicle (EV) market, SIBs have undoubtedly brought about a much-needed balance to the world, where large-scale ESDs can be utilized to store electricity. Though exploitation of layered oxide cathode materials for SIBs has had a major impact, upon repeated sodium (de)intercalation, phase transition and volume expansion of these materials have been the major limitations to the realization of SIBs as mainstream ESDs. Notably, the recent development of phase transition-free, layered copper-doped sodium manganese oxide Na_2.3Cu_1.1Mn₂O_7−δ (NCuMnO) as a cathode material has helped to overcome the major limitation of sodium layered oxide materials. In the present study, we prepared NCuMnO nanoflakes by an ultrafast pyrosynthesis process and utilized them for the fabrication of SIBs. The ex situ XANES, in situ X-ray diffraction and galvanostatic intermittent titration technique results revealed the occurrence of a highly reversible electrochemical process at the NCuMnO cathode. With the novel material, superior average discharge capacities of 127 mA h g⁻¹ and 79.24 mA h g⁻¹ at rates of 0.2C and 20C, respectively were achieved, which were attributed to fast sodium-ion diffusion, and an exceptionally high specific energy of 457.2 W h kg⁻¹ at a specific power of 72 W h kg⁻¹ were achieved.

中文翻译：

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Na _2.3 Cu _1.1 Mn ₂ O _{7- δ}纳米片作为通过快速热合成方法获得的高能钠离子电池的增强阴极材料†

在现代电子世界的锂离子电池（LIB）时代，研究人员开发了众多的能量存储设备（ESD），其中包括钠离子电池（SIB）。无论SIB是否能替代电动汽车（EV）市场中的LIB，SIB无疑已为世界带来了急需的平衡，在世界上可以利用大型ESD来存储电力。尽管开发用于SIB的层状氧化物阴极材料已产生重大影响，但在反复进行钠（脱）插层过程中，这些材料的相变和体积膨胀已成为将SIB成为主流ESD的主要限制。值得注意的是，无相过渡的层状掺杂铜的钠锰氧化物Na _2.3 Cu _1.1 Mn ₂的最新发展O _{7- δ}（NCuMnO）作为阴极材料有助于克服钠层氧化物材料的主要局限性。在本研究中，我们通过超快热合成工艺制备了NCuMnO纳米薄片，并将其用于SIB的制造。所述易地XANES，原位X射线衍射和恒电流间歇滴定技术结果揭示一个高度可逆的电化学过程的在NCuMnO阴极发生。借助这种新型材料，卓越的平均放电容量为127 mA hg ^-1和79.24 mA hg ^-1归因于钠离子快速扩散，分别达到了0.2C和20C的速率，并且在72 W h kg ^-1的比功率下获得了457.2 W h kg ^-1的极高的比能。