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For pursing high-performance supercapacitors, both of the design strategy and structural characteristic of electrode materials are crucial. Herein, we report the in-situ growth of flexible self-assembled 3D hollow tubular Cu2S nanorods on Cu foam substrate (Cu2S@Cu). The Cu substrate is simultaneously acted as a copper source and a collector, which reduces the contact resistance. Moreover, the highly ordered 3D unique structure increases the redox reactive sites and enhances the ion transmission effectively, resulting in greatly improved electrochemical performance. Based on the Cu2S@Cu electrode, the supercapacitor exhibits high areal capacitance of 1000 mF cm−2 at a current density of 2 mA cm−2, and great cycle stability, maintaining 96.9% capacitance after 10,000 cycles. Furthermore, the supercapacitor also shows an excellent flexibility with no significant decrease in the twisting or bending state. The capacity retention rates are 99.8% and 86.1%, respectively, and finally recover to 99.3%, confirming its great potential in practical application for portable electronic devices. Keywords: in-situ, 3D hollow tubular Cu2S nanorods, Flexible, Supercapacitor

Transition metal oxides can easily lose electrons and thus possess multiple accessible valences. Especially, if two different transition metals are combined, better capacity and cycling stability are achieved. In this study, a binary transition metal oxide, CoV2O6, was synthesized via a facile co-precipitation process for use as a supercapacitor cathode; the as-synthesized CoV2O6 exhibited high-capacity (306.6 F g−1, 1 A g−1 and 219.2 F g−1, 20 A g−1) and stable cycling stability, retaining 83.3% of its initial specific capacitance after 20 000 cycles. We believe that this facile synthesis process presents an effective method and a new opportunity for promoting the application of electrode materials based on binary transition metal oxides in supercapacitors.

Riparian ecosystem services along higher-order streams and connected tributaries may change over time as disturbances continuously increase, resulting in diverse deterioration of buffer zones. How habitat, plant cover, regeneration, erosion, and exotic parameters (riparian health conditions) change within huge dams and reservoirs worldwide is an unanswered question. We used multivariate statistical techniques to assess changes in riparian health parameters affected by disturbances identified in 304 transects within the Three Gorges Dam Reservoir, China, and associated tributaries. Kruskal-Wallis tests (p 0.01) revealed high diversity in habitat, plant cover, regeneration, erosion, and overall stream condition. There was also notable variance relating to exotic and pressure parameters. The critical variables of riparian health indicators and stress factors identified by principal component analysis explained 58.40% and 74.6% (in the main waterway) and 53.23% and 71.0% (in the tributaries) of the total variance. Among riparian health indicators, one habitat parameter (riparian vegetation width) in the main waterway and one regeneration parameter (tree size classes) in tributaries contributed greatly, along with other specified parameters. Furthermore, stress factors such as farming systems, land-use types, and pollutant activity variables had the highest impact on these water bodies. In comparison, counting stress factors alone showed more deterioration in the main waterway with a range of (r = -0.527- 0.493), as determined using Pearson correlation (p 0.05). Furthermore, after indexing, the parameters exhibited weaker coefficient values in tributaries, where exotic correlated negatively with other indexed values. These findings are relevant for managers of massive dam and reservoir ecosystems seeking to mitigate environmental and socioeconomic losses.

Cu2SnS3 is considered as an emerging potential candidate for electrode materials due to considerable interlayer spaces and tunnels in its crystal structures and excellent conducting ability. Ternary Cu2SnS3 as anode in lithium ion batteries has already been reported, but it is rarely mentioned to be applied in supercapacitors which is considered to be a complementary energy storage device for lithium ion batteries. It is an effective method to improve the electrochemical performance of materials by adjusting the morphology and microstructure of materials. In present study, ternary nanosheet-assembled Cu2SnS3 microspheres (M-CTS) and nanoparticles-like Cu2SnS3 (N-CTS) are synthesized via a facile solvothermal route. The results suggest that Cu2SnS3 microspheres (M-CTS) exhibit better capacitive performance compared with Cu2SnS3 (N-CTS) nanoparticles, which means that morphology does have a significant effect on the electrochemical reaction. M-CTS presents excellent supercapacitor performances with the high...

The function and performance of supercapacitors are determined by materials. However, their rational design is of paramount importance as well. In this paper, we report on a three-dimensional coral-like Ni2P-ACC nanostructure as binder-free electrode for greatly improved supercapacitor. This strategy is aimed first at forming a unique structure for lager redox-active sites and better spatial utilization, and second at producing greater conductivity and a hydrophilic high-polarized surface, which enhances the migration rate of ions between the electrolyte and the exposed surface. When Ni2P-ACC is employed as a positive electrode, it exhibits high areal capacity (2438 mF cm−2 or 3352 F g−1), and super-long cycle life (99% and 97.7% charge retentions after 5000 and 10,000 cycles, respectively). In addition, the ASC device with Ni2P-ACC and activated carbon electrodes also shows high areal capacity and long-term stability (88.8% retention of specific capacitance for 10,000 cycles). These results indicate that coral-like Ni2P-ACC nanostructure can be expected to become the candidate for supercapacitor electrodes in energy conversion.

Skutterudite CoP3 holds a unique structural formation that exhibits much better electronic properties for obtaining high energy density supercapacitors. Herein, novel skutterudite Ni-CoP3 nanosheets are constructed by etching and coprecipitating at room temperature and subsequent low-temperature phosphorization reaction. Benefiting from the enhanced electrical conductivity and more electroactive sites brought about by adjusting the electronic structure with Ni incorporating the Ni-CoP3 electrode with a battery-type demonstrates an ultrahigh specific capacity of 0.7 mA h cm-2 and exceptional cycling stability. The asymmetric supercapacitor (ASC) device fabricated by employing Ni-CoP3 and activated carbon (AC) as positive and negative electrodes, resepectively, exhibits a remarkable high energy density of 89.6 Wh kg-1 at 796 W kg-1 and excellent stability of 93% after 10 000 cycles, due to the skutterudite structure. The skutterudite Ni-CoP3 shows a great potential to be an excellent next-generation electrode candidate for supercapacitors and other energy storage devices.