With novel hierarchical hexagonal prism arrays, a carbon-doped mixed-valence Co–Mn–Fe phosphide electrode shows high capacitance, rate capability and cycling stability.

We report a significant advance toward the rational design and fabrication of stretchable and robust flexible electrodes with favorable hierarchical architectures constructed by homogeneously distributed α-fe 2 o 3 nanobelt arrays rooted in the surface layer of nanoporous carbon tube textile (NPCTT). New insight into alkali activation assisted surface etching of carbon and in-situ catalytic anisotropic growth is proposed, and is experimentally demonstrated by the synthesis of the fe 2 o 3 nanobelt arrays/npctt. the fe 2 o 3 /NPCTT electrode shows excellent flexibility and great stretchability, especially has a high specific areal capacitance of 1846 mF cm −2 at 1 mA cm −2 and cycling stability with only 4.8% capacitance loss over 10,000 cycles at a high current density of 20 mA cm −2. A symmetric solid-state supercapacitor with the fe 2 o 3 /NPCTT achieves an operating voltage of 1.75 V and a ultrahigh areal energy density of 176 µWh cm −2 (at power density of 748 µW cm −2), remarkable cycling stability, and outstanding reliability with no capacity degradation under repeated large-angle twisting. Such unique architecture improves both mechanical robustness and electrical conductivity, and allows a strong synergistic attribution of fe 2 o 3 and npctt. the synthetic method can be extended to other composites such as Mno nanosheet arrays/npctt and co 3 o 4 nanowire arrays/ NPCTT. This work opens up a new pathway to the design of high-performance devices for wearable electronics. The urgent demand for solving the future energy crisis and increasing environmental concerns has motivated the development of high-performance green energy conversion and storage devices. Among various emerging energy storage technologies, supercapacitors (SCs), which bridge the gap between conventional dielectric capacitors (with high power output) and batteries (with high energy storage), are currently attracting significant attention due to their high power density, fast charge-discharge rate, and long cycle life 1-3. However, one of the key challenges that limits SCs' practical applications is to increase their areal/volumetric energy density to the value approaching to or even exceeding that of conventional batteries without sacrificing other performance 4-7. On the other side, next-generation electronics are expected to be flexible and wearable 8-10 , it is thus highly required to develop flexible advanced electrode materials with favorable architectures allowing large porosity,

No abstract