Zhao Chenglong, Avdeev Maxim, Chen Liquan, Hu Yong-Sheng
Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, 2234, Australia.
Angew Chem Int Ed Engl. 2018 Jun 11;57(24):7056-7060. doi: 10.1002/anie.201801923. Epub 2018 May 14.
Layered transition metal oxides Na MO (M=transition metal) with P2 or O3 structure have attracted attention in sodium-ion batteries (NIBs). A universal law is found to distinguish structural competition between P2 and O3 types based on the ratio of interlayer distances of the alkali metal layer d and transition-metal layer d . The ratio of about 1.62 can be used as an indicator. O3-type Na Mg Ti O oxide is prepared as a stable anode for NIBs, in which the low Na-content (ca. 0.66) usually undergoes a P2-type structure with respect to Na MO . This material delivers an available capacity of about 98 mAh g within a voltage range of 0.4-2.0 V and exhibits a better cycling stability (ca. 94.2 % of capacity retention after 128 cycles). In situ X-ray diffraction reveals a single-phase reaction in the discharge-charge process, which is different from the common phase transitions reported in O3-type electrodes, ensuring long-term cycling stability.
具有P2或O3结构的层状过渡金属氧化物NaMO（M =过渡金属）在钠离子电池（NIBs）中受到关注。发现了一条通用规律，可根据碱金属层间距d与过渡金属层间距d的比值来区分P2型和O3型之间的结构竞争。约1.62的比值可作为一个指标。制备了O3型NaMgTiO氧化物作为NIBs的稳定阳极，其中低钠含量（约0.66）相对于NaMO通常呈现P2型结构。这种材料在0.4 - 2.0 V的电压范围内提供约98 mAh g的可用容量，并表现出更好的循环稳定性（128次循环后容量保持率约为94.2%）。原位X射线衍射揭示了充放电过程中的单相反应，这与O3型电极中报道的常见相变不同，确保了长期循环稳定性。
