基于Fe/Co-MOF制备的高性能镍铁电池铁电极及其电化学性能

铁电极是构筑高性能镍铁电池的关键。本文报道了一种基于Fe/Co-MOF制备镍铁电池铁电极的新思路,并系统研究了该材料的电化学性能。XRD、SEM和HRTEM等结果表明,Fe/Co-MOF烧结产物以八面体颗粒为主,主要由Fe_3O_4相及少量Fe-Co合金构成。作为镍铁电池的阳极时,相比于未加入Co的材料,目标材料的电化学性能得到了明显改善。Fe/Co-MOF烧结产物的放电平台稳定在1.18V,比Fe-MOF烧结产物的放电平台(1.10V)高约0.08V。尽管Fe/Co-MOF烧结产物在前10次循环出现了明显的容量衰减,但之后保持了较好的循环稳定性能,在1.0A·g-1电流密度下循环90次后比容量稳定在233.1mAh·g-1,而Fe-MOF烧结后产物的比容量仅为181.2mAh·g-1。交流阻抗结果显示Fe/Co-MOF烧结产物表现出更低的电荷传递阻抗。

Iron Electrode Derived from Fe/Co-MOF and Its Electrochemical Performance for Nickel-Iron Batteries

Developing high performance iron electrodes is still a challenge for nickel-iron batteries.In this work,we reported a high-performance iron electrode material derived from Fe/Co-MOF for the first time.As shown by XRD,SEM and TEM analysis, octahedral particles consisted of Fe3O4phase and trace Fe-Co alloy were obtained by calcining the Fe/Co-MOF precursor.The im-proved performance of this hybrid as anode materials for nickel-iron batteries in comparison with the Fe-MOF alone was due to the incorporation of an appropriate amount of Co.It showed a discharge plateau at about 1.1 8 V,which was slightly higher than Fe-MOF (1.10 V).Despite the sharp capacity loss in initial 10 cycles,a stable capacity of 233.1 mAh·g-1was obtained at a current density of 1.0 A·g-1after 90 cycles,which was about 181.2 mAh·g-1higher than that of Fe-MOF derived sample.The improved electro-chemical properties may be attributed to the improved electronic conductivity and reduced ion transfer resistance.