Optimization of Electrode Materials Using Nanocarboxylic Polystyrene Promotes Accumulation for Chromium in Zea mays from Water and Soil Contamination.

Chromium is a multivalent metal with great development in the energy storage field because it can effectively improve the electrochemical performance of the material. However, chromium(VI) is soluble in water and toxic, which causes serious metal pollution in the environment. In addition, nanoplastics are difficult to degrade and easy to accumulate, which is an urgent environmental problem to be solved. Therefore, we choose Zea mays to absorb chromium ions, nanopolystyrene, nanocarboxylic polystyrene, and their complexes, which can coordinate and decompose with various polymers in Z. mays, and produce coordination, conjugation, mixed valence, and adjacent group effects. Due to the above effects, the UV-vis spectrum of the material is blueshifted; the X-ray photoelectron spectroscopy peaks of Cr 2p have a chemical shift; the pore structure is optimized; the graphitization degree is improved; the content of N, O, and Cr in the material increases; and the elements are evenly distributed. The series of optimization processes makes the electrodes exhibit excellent electrochemical performance in both supercapacitors and lithium-ion batteries. At 0.5 A·g-1, the specific capacitance of the electrode reaches 490 F·g-1. After 10,000 cycles, its specific capacitance remains at 429.3 F·g-1, and the Coulombic efficiency is 89.9%. In lithium-ion batteries, the initial discharging capacity of the electrode is 1071.7 mAh·g-1 at 0.05 A·g-1. After 5000 cycles, its specific capacity can still reach 242 mAh·g-1 at 0.2 A·g-1, and the Coulombic efficiency is above 95%.

Surfactant induced self-assembly to prepare a vanadium nitride/N,S co-doped carbon high-capacitance anode material.

The mechanism of the reaction of melamine (C3H6N6) with ammonium metavanadate and the critical role of the surfactant in this reaction were investigated. The results indicate that the complex is obtained via the reaction of C3H6N6 with VO3- after the elimination of -NH2, and the surfactant can modulate the microstructure. In addition, a vanadium nitride/N,S co-doped carbon material fabricated from the above complex exhibits a specific capacitance of 422.0 F g-1 at 0.5 A g-1. This method provides a new route for the synthesis of vanadium nitride/carbon materials.

Dual High-Conductivity Networks via Importing a Polymeric Gel Electrolyte into the Electrode Bulk.

To obtain high-ionic-conductivity and high-electron-conductivity electrode materials, we design novel dual high-conductivity networks through importing a polymeric gel electrolyte into the electrode bulk by doping gold nanoparticles, which endows the membrane electrode with not only a high electron conductivity of 1.66 s·cm-1 but also a high ionic conductivity of 2.7 × 10-2 s·cm-1, as well as a good surface area capacitance of 1098 mF·cm-2 at 0.5 mA·cm-2. The membrane electrode shows great mechanical strength, high flexibility, and tremendous stability, and the design concept based on dual conductive networks could be also applied to other electrode systems and other energy storage fields.