Layered double hydroxide (LDH) is potentially excellent supercapacitor (SC) materials, but the low conductivity and easy agglomeration limit the further improvement of their electrochemical properties. Therefore, LDHs are requisite to grow on some conductive substrates to produce high-performance SC. In this paper, the conductive two-dimensional (2D) transition metal carbides, nitrides and carbonitrides (called MXene) were explored as the substrate to directly deposit NiFe-LDH nanosheets by a one-step hydrothermal method, then a three-dimensional (3D) porous NiFe-LDH/MXene electrode was obtained. The morphology and electrochemical performance of the composite electrodes were analyzed and investigated. The results show that the NiFe-LDH/MXene electrode has larger specific capacitance (720.2 F/g) than NiFe-LDH (465 F/g), and the capacitance of the composite electrode retained 86% after 1000 cycles (only 24% for NiFe-LDH), showing excellent cycle stability. The improved electrochemical performance of the composites is caused by the stable sheet-like structure of NiFe-LDH during charge-discharge time and the conductive network formed by the MXene, which can accelerates electron transport. In addition, the asymmetric SC based on NiFe-LDH/MXene positive electrode display a power density of 758.27 W/kg at an energy density of 42.4 Wh/Kg. These results indicate the NiFe-LDH/MXene composites can be applied as the novel candidate of high-performance SC electrodes.

层状双氢氧化物（LDH）可能是极好的超级电容器（SC）材料，但低电导率和易于团聚限制了它们电化学性能的进一步提高。因此，LDH是在某些导电基板上生长以产生高性能SC所必需的。本文以导电的二维（2D）过渡金属碳化物，氮化物和碳氮化物（称为MXene）作为基材，通过一步水热法直接沉积NiFe-LDH纳米片，然后进行三维（3D）沉积。获得了多孔的NiFe-LDH / MXene电极。分析并研究了复合电极的形貌和电化学性能。结果表明，NiFe-LDH / MXene电极的比电容（720.2 F / g）比NiFe-LDH（465 F / g）大，在1000次循环后，复合电极的电容保持86％（对于NiFe-LDH，仅为24％），显示出出色的循环稳定性。NiFe-LDH在充电和放电期间具有稳定的片状结构，以及由MXene形成的导电网络（可加速电子传输）可改善复合材料的电化学性能。另外，基于NiFe-LDH / MXene正极的不对称SC在42.4 Wh / Kg的能量密度下显示出758.27 W / kg的功率密度。这些结果表明，NiFe-LDH / MXene复合材料可用作高性能SC电极的新型候选材料。NiFe-LDH在充电和放电期间具有稳定的片状结构，以及由MXene形成的导电网络（可加速电子传输）可改善复合材料的电化学性能。另外，基于NiFe-LDH / MXene正极的不对称SC在42.4 Wh / Kg的能量密度下显示出758.27 W / kg的功率密度。这些结果表明，NiFe-LDH / MXene复合材料可用作高性能SC电极的新型候选材料。NiFe-LDH在充电和放电期间具有稳定的片状结构，以及由MXene形成的导电网络（可加速电子传输）可改善复合材料的电化学性能。另外，基于NiFe-LDH / MXene正极的不对称SC在42.4 Wh / Kg的能量密度下显示出758.27 W / kg的功率密度。这些结果表明，NiFe-LDH / MXene复合材料可用作高性能SC电极的新型候选材料。