Nickel sulfide nanocrystals on nitrogen-doped porous carbon nanotubes with high-efficiency electrocatalysis for room-temperature sodium-sulfur batteries

Polysulfide dissolution and slow electrochemical kinetics of conversion reactions lead to low utilization of sulfur cathodes that inhibits further development of room-temperature sodium-sulfur batteries. Here we report a multifunctional sulfur host, NiS2 nanocrystals implanted in nitrogen-doped porous carbon nanotubes, which is rationally designed to achieve high polysulfide immobilization and conversion. Attributable to the synergetic effect of physical confinement and chemical bonding, the high electronic conductivity of the matrix, closed porous structure, and polarized additives of the multifunctional sulfur host effectively immobilize polysulfides. Significantly, the electrocatalytic behaviors of the Lewis base matrix and the NiS2 component are clearly evidenced by operando synchrotron X-ray diffraction and density functional theory with strong adsorption of polysulfides and high conversion of soluble polysulfides into insoluble Na2S2/Na2S. Thus, the as-obtained sulfur cathodes exhibit excellent performance in room-temperature Na/S batteries

Current Progress on Rechargeable Magnesium-Air Battery

Rechargeable Mg-air batteries are a promising alternative to Li-air cells owing to the safety, low price originating from the abundant resource on the earth, and high theoretical volumetric density (3832 A h L -1 for Mg anode vs 2062 A h L -1 for Li). Only a few works are related to the highly reversible Mg-air batteries. The fundamental scientific difficulties hindering the rapid development of secondary Mg-air cells are attributed to the poor thermodynamics and kinetics properties mainly owing to the MgO or MgO 2 insulating film as the initial discharge product on air-breathing cathode, contributing to the increase of a large overpotential and a high polarization. Very recently, remarkable progress on rechargeable Mg-air batteries is trying to overcome the major limitations in organic electrolytes via the combination of the first-principle calculation and experimental study. Therefore, this progress report highlights a comprehensive and concise survey of the major progress in the history of secondary Mg-air batteries, and the detailed illustrations of corresponding reaction mechanisms. The overview is devoted to open up a new area for manipulating the nanostructures to control the ideal reaction pathway in novel cell configuration and to fully understand the future Mg-air battery with improved energy density and cycling ability

Commercial Prospects of Existing Cathode Materials for Sodium Ion Storage

Sodium ion batteries (SIBs) have recently attracted considerable attention and are considered as an alternative to lithium ion batteries (LIBs), owing to the cheap price and abundance of sodium resources. However, the commercialization of SIBs has so far been impeded by the low energy density and unstable cycle life of electrodes, especially as cathodes. Although some cathode candidates with a stable cycle life and high energy density have been developed using nanotechnologies, the commercial feasibility is seldom taken into account. This research news article provides an insight into the commercial prospects of existing cathode materials for SIBs in terms of environmental friendliness, manufacturing cost, synthesis methods and electrochemical performance