Atom-economical construction of carbon nanotube architectures for flexible supercapacitors with ultrahigh areal and volumetric capacities

The manufacture of integrated and flexible electrodes with high energy and power density is crucial for the real application of flexible energy storage devices, such as supercapacitors. Despite tremendous efforts, realizing a high density of active materials on electrodes without affecting the capacity, remains a great challenge. Here, we provide a first report of the fabrication of hierarchical uniform CNTs assembled nanoarrays via an atom-economically self-sustaining CVD (SSCVD) method, which form an ideal matrix for uniformly supporting pseudocapacitance materials with ultrahigh mass-loading (>15 mg cm(-2)). The resulting electrode shows excellent performance that delivers ultrahigh areal and volumetric capacity up to 3.18 mA h cm(-2) and 63.6 mA h cm(-3) respectively, surpassing the reported best carbon and transition metal oxides/hydroxides materials. Furthermore, the hierarchical CNTs assembled nanoarchitecture derived based on the SSCVD approach is scalable and can be extended to construct other active materials for efficient energy storage and conversions.