Boyadzhieva Tanya, Koleva Violeta, Kukeva Rosica, Nihtianova Diana, Harizanova Sonya, Stoyanova Radostina
Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences Acad. G. Bonchev Str. Bldg. 11 1113 Sofia Bulgaria
Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences 1113 Sofia Bulgaria.
RSC Adv. 2020 Aug 6;10(49):29051-29060. doi: 10.1039/d0ra05698g. eCollection 2020 Aug 5.
Sodium manganese phospho-olivine, NaMnPO, is considered to be a higher-voltage alternative to the presently used iron-based electrode material, NaFePO, for sodium ion batteries. Irrespective of this advantage, the electrochemical performance of NaMnPO is still far from what is desired. Herein we provide the first report on the storage performance of NaMnPO having a structure modified by Mg substitution. The Mg-substituted phospho-olivines are prepared on the basis of ionic exchange reactions involving the participation of Mg-substituted KMnPO·HO dittmarites as structural template. Furthermore, the phosphate particles were covered with a thin layer (up to 5 nm) of activated carbon through ball-milling. The storage performance of phospho-olivines is analyzed in sodium and lithium half-ion cells, as well as in full-ion cells bio-mass derived activated carbon and spinel LiTiO as anodes. The compatibility of phospho-olivines with electrolytes is assessed by utilization of several types of lithium and sodium carbonate-based solutions. In sodium half-cell, the Mg-substituted phosphate displays a multi-phase mechanism of Na intercalation in case when NaTFSI-based electrolyte is used. In lithium half-cell, the high specific capacity and rate capability is achieved for phospho-olivine cycled in LiPF-based electrolyte. This is a consequence of the occurrence of dual Li,Na intercalation, which encompass nano-sized domains. The utilization of the Mg-substituted phospho-olivine in the full ion cell is demonstrated.
钠锰磷橄榄石（NaMnPO）被认为是一种用于钠离子电池的高压替代材料，可替代目前使用的铁基电极材料NaFePO。尽管有此优势，但NaMnPO的电化学性能仍远未达到理想状态。在此，我们首次报道了通过镁取代修饰结构的NaMnPO的存储性能。镁取代的磷橄榄石是基于离子交换反应制备的，其中涉及镁取代的KMnPO·H₂O迪特马石作为结构模板的参与。此外，通过球磨在磷酸盐颗粒上覆盖了一层薄的（高达5纳米）活性炭。在钠和锂半电池以及全电池中分析了磷橄榄石的存储性能，全电池中使用生物质衍生的活性炭和尖晶石LiTiO作为阳极。通过使用几种基于碳酸锂和碳酸钠的溶液评估了磷橄榄石与电解质的兼容性。在钠半电池中，当使用基于NaTFSI的电解质时，镁取代的磷酸盐显示出钠嵌入的多相机制。在锂半电池中，在基于LiPF的电解质中循环的磷橄榄石实现了高比容量和倍率性能。这是双锂、钠嵌入发生的结果，其包含纳米尺寸的区域。展示了镁取代的磷橄榄石在全离子电池中的应用。
