Thermally doped polypyrrole nanotubes with sulfuric acid for flexible all-solid-state supercapacitors

Ag(e)ing and Degradation of Supercapacitors: Causes, Mechanisms, Models and Countermeasures

The most prominent and highly visible advantage attributed to supercapacitors of any type and application, beyond their most notable feature of high current capability, is their high stability in terms of lifetime, number of possible charge/discharge cycles or other stability-related properties. Unfortunately, actual devices show more or less pronounced deterioration of performance parameters during time and use. Causes for this in the material and component levels, as well as on the device level, have only been addressed and discussed infrequently in published reports. The present review attempts a complete coverage on these levels; it adds in modelling approaches and provides suggestions for slowing down ag(e)ing and degradation.

Interface engineering Ni/Ni12P5@CNx Mott-Schottky heterojunction tailoring electrocatalytic pathways for zinc-air battery

Due to the poor bifunctional electrocatalytic performances of electrocatalysts in zinc-air battery, herein, we first synthesized Ni/Ni₁₂P₅@CN_x Mott-Schottky heterojunction to ameliorate the high-cost and instability of precious metals. We modulated the different contents of Ni and Ni₁₂P₅ in the Ni/Ni₁₂P₅@CN_x Mott-Schottky heterojunction, and found that 0.6 Ni/Ni₁₂P₅@CN_x has outstanding electrocatalytic performances, with half-wave potential of 0.83 V, and OER potential of 1.49 V at 10 mA cm^-2. Also, the ΔE value is only 0.66 V. Moreover, 0.6 Ni/Ni₁₂P₅@CN_x is assembled into ZAB, which has a high power density of 181 mW cm^-2 and a high specific capacity of 710 mAh g^-1. This indicates it has a good cycle stability. The density functional theory (DFT) calculations reveal that electrons spontaneously flow from Ni to Ni₁₂P₅ through the formed buffer layer in the Ni/Ni₁₂P₅@CN_x Mott-Schottky heterojunction. The Schottky barrier formed modulates the electrocatalytic pathway to have good bifunctional electrocatalytic activity for ORR and OER.

Progress in supercapacitors: roles of two dimensional nanotubular materials

Overcoming the global energy crisis due to vast economic expansion with the advent of human reliance on energy-consuming labor-saving devices necessitates the demand for next-generation technologies in the form of cleaner energy storage devices. The technology accelerates with the pace of developing energy storage devices to meet the requirements wherever an unanticipated burst of power is indeed needed in a very short time. Supercapacitors are predicted to be future power vehicles because they promise faster charging times and do not rely on rare elements such as lithium. At the same time, they are key nanoscale device elements for high-frequency noise filtering with the capability of storing and releasing energy by electrostatic interactions between the ions in the electrolyte and the charge accumulated at the active electrode during the charge/discharge process. There have been several developments to increase the functionality of electrodes or finding a new electrolyte for higher energy density, but this field is still open to witness the developments in reliable materials-based energy technologies. Nanoscale materials have emerged as promising candidates for the electrode choice, especially in 2D sheet and folded tubular network forms. Due to their unique hierarchical architecture, excellent electrical and mechanical properties, and high specific surface area, nanotubular networks have been widely investigated as efficient electrode materials in supercapacitors, while maintaining their inherent characteristics of high power and long cycling life. In this review, we briefly present the evolution, classification, functionality, and application of supercapacitors from the viewpoint of nanostructured materials to apprehend the mechanism and construction of advanced supercapacitors for next-generation storage devices.