Yao Shuyun, Ji Yingjie, Wang Shiyu, Liu Yuanming, Hou Zishan, Wang Jinrui, Gao Xueying, Fu Weijie, Nie Kaiqi, Xie Jiangzhou, Yang Zhiyu, Yan Yi-Ming
State Key Lab of Organic-Inorganic Composites, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China.
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
Angew Chem Int Ed Engl. 2024 Jun 3;63(23):e202404834. doi: 10.1002/anie.202404834. Epub 2024 Apr 30.
Transition metal oxides (TMOs) are key in electrochemical energy storage, offering cost-effectiveness and a broad potential window. However, their full potential is limited by poor understanding of their slow reaction kinetics and stability issues. This study diverges from conventional complex nano-structuring, concentrating instead on spin-related charge transfer and orbital interactions to enhance the reaction dynamics and stability of TMOs during energy storage processes. We successfully reconfigured the orbital degeneracy and spin-dependent electronic occupancy by disrupting the symmetry of magnetic cobalt (Co) sites through straightforward strain stimuli. The key to this approach lies in the unfilled Co 3d shell, which serves as a spin-dependent regulator for carrier transfer and orbital interactions within the reaction. We observed that the opening of these 'spin gates' occurs during a transition from a symmetric low-spin state to an asymmetric high-spin state, resulting in enhanced reaction kinetics and maintained structural stability. Specifically, the spin-rearranged Al-CoO exhibited a specific capacitance of 1371 F g, which is 38 % higher than that of unaltered CoO. These results not only shed light on the spin effects in magnetic TMOs but also establish a new paradigm for designing electrochemical energy storage materials with improved efficiency.
过渡金属氧化物（TMOs）在电化学储能中起着关键作用，具有成本效益且电位窗口宽广。然而，对其缓慢的反应动力学和稳定性问题的认识不足限制了它们的全部潜力。本研究不同于传统的复杂纳米结构构建，而是专注于自旋相关的电荷转移和轨道相互作用，以增强TMOs在储能过程中的反应动力学和稳定性。我们通过直接的应变刺激破坏磁性钴（Co）位点的对称性，成功地重新配置了轨道简并度和自旋相关的电子占据情况。这种方法的关键在于未填满的Co 3d壳层，它作为反应中载流子转移和轨道相互作用的自旋相关调节器。我们观察到，这些“自旋门”的打开发生在从对称低自旋态到不对称高自旋态的转变过程中，从而导致反应动力学增强和结构稳定性得以维持。具体而言，自旋重排的Al-CoO表现出1371 F g的比电容，比未改变的CoO高出38 %。这些结果不仅揭示了磁性TMOs中的自旋效应，还为设计具有更高效率 的电化学储能材料建立了新的范例。
