Fu Min, Lv Ruitao, Lei Yu, Terrones Mauricio
College of Chemical and Biological Engineering, Shandong University of Science and Technology, Qingdao, 266590, China.
School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
Small. 2021 Jan;17(1):e2004827. doi: 10.1002/smll.202004827. Epub 2020 Dec 7.
Light-weight and flexible supercapacitors with outstanding electrochemical performances are strongly desired in portable and wearable electronics. Here, ultralight nitrogen-doped carbon macrotube (N-CMT) sponges with 3D interconnected macroporous structures are fabricated and used as substrate to grow nickel ferrite (NiFe O ) nanoparticles by vapor diffusion-precipitation and in situ growth. This process effectively suppresses the agglomeration of NiFe O , enabling good interfacial contact between N-CMT sponges and NiFe O . More remarkably, the as-synthesized NiFe O /N-CMT composite sponges can be directly used as electrodes without additional processing that could cause agglomeration and reduction of active sites. Benefiting from the tubular structure and the synergetic effect of NiFe O and N-CMT, the NiFe O /N-CMT-2 exhibits a high specific capacitance of 715.4 F g at a current density of 1 A g , and 508.3 F g at 10 A g , with 90.9% of capacitance retention after 50 000 cycles at 1 A g in an alkaline electrolyte. Furthermore, flexible supercapacitors are fabricated, yielding areal specific capacitances of 1397.4 and 1041.2 mF cm at 0.5 and 8 mA cm , respectively. They also exhibit exceptional cycling performance with capacitance retention of 92.9% at 1 mA cm after 10 000 cycles under bending. This work paves a new way to develop flexible, light-weight, and high-performance energy storage devices.
便携式和可穿戴电子产品强烈需要具有出色电化学性能的轻质且柔性的超级电容器。在此，制备了具有三维互连大孔结构的超轻氮掺杂碳大管（N-CMT）海绵，并将其用作基底，通过气相扩散沉淀和原位生长来生长镍铁氧体（NiFe₂O₄）纳米颗粒。该过程有效抑制了NiFe₂O₄的团聚，使得N-CMT海绵与NiFe₂O₄之间具有良好的界面接触。更值得注意的是，所合成的NiFe₂O₄/N-CMT复合海绵无需额外加工即可直接用作电极，否则可能会导致团聚和活性位点减少。受益于管状结构以及NiFe₂O₄和N-CMT的协同效应，NiFe₂O₄/N-CMT-2在1 A g⁻¹的电流密度下表现出715.4 F g⁻¹的高比电容，在10 A g⁻¹时为508.3 F g⁻¹，在碱性电解液中于1 A g⁻¹下经过50000次循环后电容保持率为90.9%。此外，制备了柔性超级电容器，在0.5和8 mA cm⁻²时的面积比电容分别为1397.4和1041.2 mF cm⁻²。它们还表现出优异的循环性能，在弯曲状态下于1 mA cm⁻²经过10000次循环后电容保持率为92.9%。这项工作为开发柔性、轻质和高性能的储能器件开辟了一条新途径。
