Yang Junghoon, Zhang Jiliang, Lau Vincent Wing-Hei, Park Mihui, Lee Suwon, Kim Jaebum, Kang Yong-Mook
Department of Energy and Materials Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea.
Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea.
J Phys Chem Lett. 2020 May 21;11(10):4059-4069. doi: 10.1021/acs.jpclett.0c01035. Epub 2020 May 7.
We present a unique composite assembly of rhombohedral LiV(PO) and carbon nanofiber, which simultaneously facilitates Li-ion transport as well as electron transfer. For the synthesis of this composite, the inorganic precursors were confined in electron-spun nanofibers, and then, through controlled annealing, NaV(PO) particulates were grown with controllable crystallite size and partially embedded into carbon nanofibers with precisely controlled diameter. The rhombohedral LiV(PO) could be successfully obtained by ion exchange from Na to Li in the prepared NaV(PO). The final rhombohedral LiV(PO) particles anchored onto the carbon nanofibers exhibited excellent electrochemical performance with fast kinetics for Li-ion batteries. Suprisingly it maintains 69 and 41 mAh/g even at 100 as cathode and anode. Several advanced characterizations revealed that its ultrafast kinetics could be attributed to synergistic effect resulting from the distinctive microstructure of the composite and the structural superiority of highly symmetric rhombohedral LiV(PO) over its monoclinic homologue for Li-ion transport.
我们展示了一种独特的菱面体LiV(PO)与碳纳米纤维的复合组装体，其同时促进锂离子传输以及电子转移。对于这种复合材料的合成，无机前驱体被限制在静电纺丝纳米纤维中，然后通过控制退火，生长出具有可控微晶尺寸的NaV(PO)颗粒，并部分嵌入到直径精确控制的碳纳米纤维中。通过在制备的NaV(PO)中进行从Na到Li的离子交换，可以成功获得菱面体LiV(PO)。最终锚定在碳纳米纤维上的菱面体LiV(PO)颗粒对锂离子电池表现出优异的电化学性能和快速动力学。令人惊讶的是，即使在100时作为阴极和阳极，它仍保持69和41 mAh/g。几种先进的表征表明，其超快动力学可归因于复合材料独特的微观结构以及高度对称的菱面体LiV(PO)在锂离子传输方面相对于其单斜同系物的结构优势所产生的协同效应。
