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Three new D-π-A-structured organic dyes, coded as

Li-S batteries are considered to be the most promising next-generation advanced energy-storage systems. However, the sluggish reaction kinetics and the "shuttle effect" of lithium polysulfides (LiPSs) severely limit their battery performances. To overcome the complex and multiphase sulfur redox chemistry of LiPSs, in this study, we propose a new type of cobalt-based double catalytic sites (DCSs) codoped mesoporous carbon to immobilize and reversibly catalyze the LiPS intermediates in the cycling process, thus eliminating the shuttle effect and improving the charge-discharge kinetics. The theoretical calculation shows that the well-designed DCS configuration endows LiPSs with both strong and weak binding capabilities, which will facilitate the synergistic and reversible catalytic conversion. Furthermore, the experimental results also confirm that the DCS structure shows significantly enhanced catalytic kinetics than the single catalytic sites. The Li-S battery equipped with the DCS structure displays an extremely high discharge capacity of 918 mA h g-1 at a current density of 0.2 C and can reach a capacity of 867 mA h g-1 after 200 cycles with an ultralow capacity attenuation rate of 0.028% for each cycle. This study opens new avenues to address the catalytic requirements both in discharging and charging processes.

Among various photovoltaic devices, dye-sensitized solar cells (DSSCs) are one of the most potentially clean and renewable energy conversion devices because of their low fabrication cost, environmentally friendly nature, and high power conversion efficiency. However, the use of rare metals such as Pt counter electrodes (CEs) is one of the major drawbacks of DSSC devices for broad real-life applications. In this regard, alternative materials to Pt CEs have been long sought for DSSCs employing both cobalt and iodine redox couples. Therefore, in this study, soft-templated tellurium-doped mesoporous carbons (Te-SMCs) were synthesized for the first time by the simple pyrolysis of PAN- b-PBA block copolymer in the presence of a tellurium precursor for replacing the Pt CE. To confirm the chemical composition and porosity, the as-prepared Te-SMC materials were evaluated by elemental analysis (XPS and EDS) and nitrogen sorption isotherms measurement. The as-prepared Te-SMC materials contained mainly mesopores and retained the three-dimensional hierarchical graphite-like structure with many defect sites. They displayed doping levels with nitrogen of 9.15 atom % and tellurium of 0.15 atom % and had a specific surface area of 540 m