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Improving the atomic utilization of storage sites and developing isotropic transport characteristics become crucial to enhance the performance of potassium‐ion hybrid capacitors (PIHCs), and the disordered strategy and coordination modulation of the electrodes can satisfy the above structure‐activity requirements. Herein, the highly dispersed atomic W‐P clusters are chosen as a platform for the electronic restructuring. Studies and calculations indicate that replacing O in W‐O2/P2 with pyridine N can modulate the electron distribution and electronegativity, and enrich the edge‐dangling bonds of the amorphous clusters (W‐N2/P2), resulting in proper adsorption equilibrium and high affinity for K+ storage. In addition, the clusters have isotropic and bulk‐phase‐indifferent fast ion storage, and in situ protection of carbon nanosheets can provide stable support for ion storage and electron transfer in the clusters. As an anode, the composite (W‐N/P@C) exhibits superior storage properties of K+ (reversible capacity of 181.6 mAh g−1 after 3000 cycles at 5.0 A g−1), with high energy density (163.7 Wh Kg−1) at the high‐power output (3500 W Kg−1) in PIHCs. This work systematically delineates the effects of disordered design and pyridine N‐coordination on energy storage, and provides new research ideas for studying high‐performance PIHCs. [ABSTRACT FROM AUTHOR]

Converting CO2 into value-added fuels or chemical feedstocks through electrochemical reduction is one of the several promising avenues to reduce atmospheric carbon dioxide levels and alleviate global warming. This approach has mild operating conditions, adjusts product distribution, allows modular design, and offers opportunities for carbon-intensive manufacturing industries to utilize renewable energy power for CO2 reduction. In recent decades, various valid methods and strategies have been developed for high efficiency and high selectivity electrocatalysts to reduce CO2. Unfortunately, while intensive research focuses on the development of new electrocatalysts, little attention has been paid to the engineering design of low-cost and large-scale CO2 reduction electrolyzer architectures, which impairs the full realization of potential benefits of new electrocatalysts. This review summarizes the recent progress of reactor architectures and system engineering in the CO2 reduction reaction. We discuss how to improve the performance of the CO2 reduction reaction from four aspects: (i) flow cell architectures, (ii) management of reactant delivery, (iii) membranes, and (iv) electrolytes. We aim to introduce reactor architectures and system engineering strategies in detail to enable further development and provide inspiration for potential industrial applications of CO2 reduction. [ABSTRACT FROM AUTHOR]

If counter electrodes (CEs) could also contribute to light harvesting in dye‐sensitized solar cells (DSSCs), then the power conversion efficiency (PCE) of DSSCs would be further boosted without changing the device structure. Nearly monodispersed Ag2Se nanocrystals with a bandgap of 1.62 eV (∼765 nm) were synthesized via a one‐pot process, and Ag2Se CEs were fabricated by using a spin‐coating and annealing process. Incident photon‐to‐current conversion efficiency and photocurrent spectra indicated that Ag2Se CEs can generate the electricity by harvesting more visible light, which could not be absorbed by dye‐sensitized photoanodes. Thus, compared to Pt CE (7.57 %), the DSSC based on Ag2Se CE exerted a higher PCE of 8.06 %. The development of photovoltaic CEs may offer an alternative way to promote the performance and competitiveness of DSSCs. Photovoltaic counter electrodes not only catalyse I3− reduction, but also harvest transmitted photons of photoanodes to increase the photocurrent of DSSCs (see figure). This offers an alternative method for enhancing the performance and competitiveness of DSSCs. [ABSTRACT FROM AUTHOR]

Abstract: The electrocatalytic performances of semiconductors are closely correlated to their energy structures, and solid solutions can continuously tune the energy structures by controlling their composition. Herein, a series of Fe1‐xCoxS2 (x=0–0.5) solid solutions have been synthesized and served as counter electrodes in dye‐sensitized solar cells (DSSCs). The Fermi level of Fe1‐xCoxS2 solid solutions shifted negatively as the x value changed from 0 to 0.5, and the electrocatalytic performance for I3− reduction gradually enhanced due to the facilitated electron transfer process from electrode to I3−. Benefitting from its negative Fermi level, Fe0.5Co0.5S2 exhibited the smallest charge transfer resistance (Rct) and remarkable electrocatalytic properties. The DSSCs using Fe0.5Co0.5S2 as a counter electrode achieve the lowest Rct (0.84 Ω cm2) and the highest power conversion efficiency (η=8.36%) of these solid solution materials. [ABSTRACT FROM AUTHOR]

Wurtz-stannite Cu2CdGeS4 nanocrystals were synthesized via a facile hot-injection method at a low temperature. They exhibited low charge transfer resistance at the electrolyte–electrode interface and high electrocatalytic activity for the reduction of I3− in dye-sensitized solar cells (DSSCs). Moreover, this DSSC showed a power conversion efficiency of 7.67%, comparable to the Pt-based device (7.54%). [ABSTRACT FROM AUTHOR]

A covalently tethered polyoxometalate (POM)-pyrene hybrid (Py-SiW11) is utilized for the noncovalent functionalization of single-walled carbon nanotubes (SWNTs). The resulting SWNTs/Py-SiW11 nanocomposite shows that both SiW11 and pyrene moieties could interact with SWNTs without causing any chemical decomposition. When used as anode material in lithium-ion batteries, the SWNTs/Py-SiW11 nanocomposite exhibits higher discharge capacities, and better rate capacity and cycling stability than the individual components. When the current density is 0.5 mA cm−2, the nanocomposite exhibits the initial discharge capacity of 1569.8 mAh g−1, and a high discharge capacity of 580 mAh g−1 for up to 100 cycles. [ABSTRACT FROM AUTHOR]

Aqueous polysulfide/iodide redox flow batteries are attractive for scalable energy storage due to their high energy density and low cost. However, their energy efficiency and power density are usually limited by poor electrochemical kinetics of the redox reactions of polysulfide/iodide ions on graphite electrodes, which has become the main obstacle for their practical applications. Here, CoS2/CoS heterojunction nanoparticles with uneven charge distribution, which are synthesized in situ on graphite felt by a one-step solvothermal process, can significantly boost electrocatalytic activities of I−/I3− and S2−/Sx2− redox reactions by improving absorptivity of charged ions and promoting charge transfer. The polysulfide/iodide flow battery with the graphene felt-CoS2/CoS heterojunction can deliver a high energy efficiency of 84.5% at a current density of 10 mA cm−2, a power density of 86.2 mW cm−2 and a stable energy efficiency retention of 96% after approximately 1000 h of continuous operation. Polysulfide/iodide redox flow batteries are promising due to low cost and high-solubility components, but are limited by energy efficiency and power density. Here the authors fabricate heterojunction electrocatalysts to achieve improved performance in a polysulfide/iodide redox flow battery. [ABSTRACT FROM AUTHOR]

Platinum (Pt)-based alloys are considerably promising electrocatalysts for the reduction of I - /I 3 - and Co 2+ /Co 3+ redox couples in dye-sensitized solar cells (DSSCs). However, it is still challenging to minimize the dosage of Pt to achieve comparable or even higher catalytic efficiency. Here, by taking full advantages of the Mott-Schottky (M-S) effect at the metal-semiconductor interface, we successfully strategize a low-Pt-based M-S catalyst with enhanced electrocatalytic performance and stability for the large-scale application of DSSCs. The optimized M-S electrocatalyst of Ni 3 S 4 -Pt 2 X 1 (X = Fe, Ni) heteronanorods is constructed by rationally controlling the ratio of Pt to transition metal in the hybrids. It was found that the electrons transferred from Ni 3 S 4 to Pt 2 X 1 at their interface under the Mott-Schottky effect result in the concentration of electrons onto Pt 2 X 1 domains, which subsequently accelerates the regeneration of both I - /I 3 - and Co 2+ /Co 3+ redox shuttles in DSSCs. As a result, the DSSC with Ni 3 S 4 -Pt 2 Fe 1 manifests an impressive power conversion efficiency (PCE) of 8.79% and 5.56% for iodine and cobalt-based electrolyte under AM1.5G illumination, respectively. These PCEs are obviously superior over those with Ni 3 S 4 -Pt, PtFe, Ni 3 S 4 , and pristine Pt electrodes. The strategy reported here is able to be further expanded to fabricate other low-Pt-alloyed M-S catalysts for wider applications in the fields of photocatalysis, water splitting, and heterojunction solar cells.

Wurtz-stannite Cu2CdGeS4 nanocrystals were synthesized via a facile hot-injection method at a low temperature. They exhibited low charge transfer resistance at the electrolyte-electrode interface and high electrocatalytic activity for the reduction of I3(-) in dye-sensitized solar cells (DSSCs). Moreover, this DSSC showed a power conversion efficiency of 7.67%, comparable to the Pt-based device (7.54%).