KOH-activated hollow carbon spheres with surface functionalization for high-capacity and long-cycle-life lithium-selenium batteries.

Lithium-selenium (Li-Se) batteries are considered promising alternatives to lithium-ion batteries due to their higher volumetric capacity and energy density. However, they still face limitations in efficiently utilizing the active selenium. Here, we develop surface-functionalized mesoporous hollow carbon nanospheres as the selenium host.

Self-Supported Transition Metal-Based Nanoarrays for Efficient Energy Storage.

Rechargeable batteries and supercapacitors are currently considered as promising electrochemical energy storage (EES) systems to address the energy and environment issues. Self-supported transition metal (Ni, Co, Mn, Mo, Cu, V)-based materials are promising electrodes for EES devices, which offer highly efficient charge transfer kinetics. This review summarizes the latest development of transition metal-based materials with self-supported structures for EES systems.

Tuning oxygen reduction activity on chromia surface via alloying: a DFT study.

Economical electro-catalysts for the oxygen reduction reaction (ORR) are highly desirable for a range of advance energy storage technologies. Chromium compounds have been suggested as one possible source of non-precious metal based catalysts for oxygen reduction reaction (ORR), especially chromia (Cr O ) which is the most stable form of Cr oxide at room temperature. Using density functional theory+U calculations, we investigate the 4-electron ORR on the hydroxylated Cr O surfaces alloyed with 17 different transition metals.

Three Dimensionally Free-Formable Graphene Foam with Designed Structures for Energy and Environmental Applications.

Three-dimensional assemblies of graphene have been considered as promising starting materials for many engineering, energy, and environmental applications due to its desirable mechanical properties, high specific area, and superior thermal and electrical transfer ability. However, little has been done to introduce designed shapes into scalable graphene assemblies. In this work, we show here a combination of conventional graphene growing technique-chemical vapor deposition with additive manufacturing.

Development of a Nanostructured α-MnO/Carbon Paper Composite for Removal of Ni/Mn Ions by Electrosorption.

Toxic metal ions, such as Ni and Mn, in industrial waste streams are nonbiodegradable and can cause damage to the human body. Electrochemical cleaning techniques are attractive as they offer more control and produce less sludge than do chemical/biological approaches without the high pressures needed for membranes. Here, nanoneedle-structured α-MnO/carbon fiber paper (CFP) composites were synthesized by a hydrothermal approach and used as electrodes for combined electroadsorption and capacitive deionization removal of nickel and manganese ions from pseudoindustrial waste streams.

Rational Design of Self-Supported NiS Nanosheets Array for Advanced Asymmetric Supercapacitor with a Superior Energy Density.

We report a rationally designed two-step method to fabricate self-supported NiS nanosheet arrays. We first used 2-methylimidazole (2-MI), an organic molecule commonly served as organic linkers in metal-organic frameworks (MOFs), to synthesize an α-Ni(OH) nanosheet array as a precursor, followed by its hydrothermal sulfidization into NiS. The resulting NiS nanosheet array demonstrated superior supercapacitance properties, with a very high capacitance of about 1,000 F g being delivered at a high current density of 50 A g for 20,000 charge-discharge cycles.