原位生长钴基MOF的碳纳米纤维材料的制备及其锂电性能研究

Preparation and Lithium Storage Properties of Carbon Nanofiber Materials with in Situ Grown Cobalt-Based MOF

金属有机框架(MOFs)材料因其具有高度可控的结构以及可调的孔隙率而在电池材料领域应用广泛。但由于MOFs类材料较低的电导率以及堆叠结构带来的活性位点利用率低等问题使其难以直接用作电极材料。因此,发展MOFs材料电极仍然存在挑战。本文将表面含有Co^(2+)离子的多孔炭纤维在高温高压条件下与含对苯二甲酸根的蒸汽进行反应。通过气-固反应的方法在碳纤维表面原位生长Co-MOF,制备负载纳米级Co-MOF颗粒的碳纳米纤维复合材料,并对该复合材料的结构形貌以及锂电池性能进行分析。多孔碳纤维的引入以及较小尺寸的MOF生成使得复合材料的导电性和稳定性得到了极大的提高。当被用作锂离子电池的负极时,Co-MOF/Pcnf在0.1 A/g的电流密度下循环100次后具有1081 mAh/g的可逆容量;在1 A/g的大电流密度下循环1000次后仍具有623.4 mAh/g的可逆容量。本研究为发展MOFs材料电极提供新的发展思路。

Metal-organic frameworks(MOFs)materials are widely used in the field of battery materials because of their highly controllable structure and tunable porosity.However,the low conductivity of MOFs and the low utilization of active sites due to the stacked structure make them difficult to be used as electrode materials directly.In this paper,carbon nanofiber composites loaded with nanoscale Co-MOF particles were prepared by in situ growth of Co-MOF on the fiber surface through the gas-solid reaction method,and the structural morphology and lithium battery properties of the composites were analyzed.The introduction of porous carbon fibers and the generation of smaller-size MOFs have greatly improved the electrical conductivity and stability of the composites.When used as the negative electrode of Li-ion batteries,the Co-MOF/Pcnf has a reversible capacity of 1081 mAh/g after 100 cycles at a current density of 0.1 A/g,and still has a reversible capacity of 623.4 mAh/g after 1000 cycles at a high current density of 1 A/g.