As an all-inorganic zero-dimensional (0D) lead-free metal halide, Cs2ZnCl4 is a potentially excellent matrix for preparing chemically stable and environmentally friendly photoluminescent materials ...through an ion-doping strategy. Therefore, it is necessary to study the emission properties of every kind of doping ion in the tetrahedral coordination of Cs2ZnCl4. Here, for the first time, we successfully synthesized Te4+-doped Cs2ZnCl4 single crystals via a facile hydrothermal method. X-ray crystallography clearly reveals the strong distortion of the tetrahedral units in Cs2ZnCl4 caused by doping with Te4+. Broadband yellow-light emission covering the range from 450 nm to 700 nm with a large Stokes shift is observed in Cs2ZnCl4:Te4+ single crystals, and this is attributed to self-trapped excitons (STEs) caused by the lattice vibration of the distorted structure. It is worth mentioning that this broadband yellow phosphor can be excited by a wide range of blue light, implicitly giving it an excellent ability to adapt to multiple models of blue LED chips, thus serving as a suitable yellow phosphor that can be applied to fabricate WLEDs without the need to worry about the lack of red light.
The commercialization of lithium–sulfur (Li–S) battery is seriously hindered by the shuttle behavior of lithium (Li) polysulfide, slow conversion kinetics, and Li dendrite growth. Herein, a novel ...hierarchical p‐type iron nitride and n‐type vanadium nitride (p‐Fe2N/n‐VN) heterostructure with optimal electronic structure, confined in vesicle‐like N‐doped nanofibers (p‐Fe2N/n‐VN⊂PNCF), is meticulously constructed to work as “one stone two birds” dual‐functional hosts for both the sulfur cathode and Li anode. As demonstrated, the d‐band center of high‐spin Fe atom captures more electrons from V atom to realize more π* and moderate σ* bond electron filling and orbital occupation; thus, allowing moderate adsorption intensity for polysulfides and more effective d–p orbital hybridization to improve reaction kinetics. Meanwhile, this unique structure can dynamically balance the deposition and transport of Li on the anode; thereby, more effectively inhibiting Li dendrite growth and promoting the formation of a uniform solid electrolyte interface. The as‐assembled Li–S full batteries exhibit the conspicuous capacities and ultralong cycling lifespan over 2000 cycles at 5.0 C. Even at a higher S loading (20 mg cm−2) and lean electrolyte (2.5 µL mg−1), the full cells can still achieve an ultrahigh areal capacity of 16.1 mAh cm−2 after 500 cycles at 0.1 C.
A novel hierarchical p‐Fe2N/n‐VN heterostructure with optimal electronic structure is constructed as the electrode of a bifunctional lithium–sulfur battery. The formed p–n heterostructures have reasonable D‐band centers, achieving more π* and medium σ* bonding electrons to occupy in filled and anti‐bonding states; thus, dynamically balancing the electrochemical reaction processes of S and Li.
In this study, cuboid‐like anhydrous CoC2O4 particles (CoC2O4‐HK) are synthesized through a potassium citrate‐assisted hydrothermal method, which possess well‐crystallized structure for fast Li+ ...transportation and efficient Li+ intercalation pseudocapacitive behaviors. When being used in lithium‐ion batteries, the as‐prepared CoC2O4‐HK delivers a high reversible capacity (≈1360 mAh g‐1 at 0.1 A g‐1), good rate capability (≈650 mAh g‐1 at 5 A g‐1) and outstanding cycling stability (835 mAh g‐1 after 1000 cycles at 1 A g‐1). Characterizations illustrate that the Li+‐intercalation pseudocapacitance dominates the charge storage of CoC2O4‐HK electrode, together with the reversible reaction of CoC2O4+2Li++2e−→Co+Li2C2O4 on discharging and charging. In addition, CoC2O4‐HK particles are also used together with carbon–sulfur composite materials as the electrocatalysts for lithium–sulfur (Li–S) battery, which displays a gratifying sulfur electrochemistry with a high reversibility of 1021.5 mAh g−1 at 2 C and a low decay rate of 0.079% per cycle after 500 cycles. The density functional theory (DFT) calculations show that CoC2O4/C can regulate the adsorption‐activation of reaction intermediates and therefore boost the catalytic conversion of polysulfides. Therefore, this work presents a new prospect of applying CoC2O4 as the high‐performance electrode materials for rechargeable Li‐ion and Li–S batteries.
Well‐crystallized CoC2O4 particles are synthesized by the chelating agent‐assisted hydrothermal method, which display fast Li+ transportations and efficient Li+ intercalation pseudocapacitive behaviors to achieve outstanding Li‐ion performance. CoC2O4 particles are also used together with carbon–sulfur composite materials as the electrocatalysts for lithium–sulfur battery, which delivers a gratifying sulfur electrochemistry with a high reversibility and long cycling lifespan.
Amidst the rapid expansion of the new energy sector, lithium–sulfur (Li–S) batteries have garnered significant interest due to their high energy density and eco-friendliness. However, challenges such ...as the shuttle effect have hindered Li–S batteries from realizing their full potential. To address the shuttle effect and its associated issues, researchers have embarked on material studies using various approaches. This review presents recent progress in the study of catalysts based on iron-containing oxides, highlighting key advancements in the field. Initially, it elucidates the catalytic mechanisms of iron-based oxides, encompassing physical confinement, chemical adsorption, and catalysis. Subsequently, it delves into the meticulous design and optimization of catalysts employing five strategies: structural engineering, oxygen vacancy manipulation, heterostructure formation, heteroatom doping, and energy band engineering. Lastly, it offers a concise summary and future outlook on iron-based oxide catalysts.
The construction of heterostructures is one of the most promising strategies for engineering interfaces of catalysts to perform high-efficiency oxygen evolution reaction (OER). However, accurately ...tuning heterostructures’ interface during operation remains a challenge. Herein, we fabricated the needled-like heterostructure Co1–x S/Co(OH)F supported on flexible carbon fiber cloth via an atomic substitution strategy, in which sulfur atoms are simultaneously grafted into F vacancies after the partial removal of F atoms from Co(OH)F during the electrodeposition, thus achieving the growth of cobalt sulfide on the interface of Co(OH)F. This electrocatalyst with such design exhibits the following advantages: (1) The lattice distortion caused by atomic substitution leads to the increase of active sites; (2) Co1–x S constructed on the surface of Co(OH)F by the atomic replacement strategy optimizes the adsorption (OH–) and desorption (O2) energy in the OER process; (3) the needle-like structure possesses the tip-enhanced local electric field effect. As a result, the Co1–x S/Co(OH)F/CC catalyst exhibits very high OER catalytic performance with an overpotential of 269 mV at a current density of 10 mA cm–2 and a Tafel slope of 71 mV dec–1. The asymmetric electrode shows superior catalytic activity and stability in overall water splitting. The catalytic mechanism of these highly efficient Co1–x S/Co(OH)F/CC catalysts was investigated via DFT theoretical calculations and ex situ characterizations. This atomic substitution strategy displays universality for other transition metal sulfides (metal = Ni, Mn, Cu).
The bismuth oxycarbonate (Bi2O2CO3) material with a strong electric field as intercalation of lithium-sulfur battery to effectively catalyze the transformation of polysulfide and inhibit shuttle ...effect.
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The shuttle effect of polysulfides is a major challenge for the commercialization of lithium-sulfur battery. The systematic modification of separators has the potential to solve these problems by enhancing the adsorption and catalytic conversion of polysulfides. Herein, strong internal electric field bismuth oxycarbonate (Bi2O2CO3) nanoflowers decorated conductive carbon (DC + BOC) is proposed to be systematically modified on separator. This intermediate layer not only possesses a strong affinity for polysulfides, but also promotes the conversion of polysulfides and induces the formation of a stable solid electrolyte interphase (SEI) layer, thereby improving the rate performance and cycling stability of the battery. As expected, the modified membrane achieved a high specific capacity of 713 mA h g−1 at 5 C. At 1 C, high reversibility of 719 mA h g−1 was achieved after 550 cycles with only 0.044% decay per cycle. More importantly, under the sulfur loading of 5.1 mg cm−2, the area specific capacity remained at 4.1 mA h cm−2 after 200 cycles, and the attenuation rate per cycle was only 0.056%. This work provides a new strategy to overcome the shuttle effect of polysulfide, and shows great potential in the application of high-performance lithium-sulfur batteries.
We reported a template-free and facile synthetic route to engineer thickness-tunable ultrathin two-dimensional (2D) porous carbon nanosheets (U-PCNS) for advanced lithium–sulfur batteries. The ...thickness-dependent interfacial properties, e.g., the specific surface area, porosity, and the oxygen doping level, have significantly improved mass/charge transfer and polysulfide chemisorption of U-PCNS. It is worth noting that the thickness of U-PCNS is vitally sensitive to the initial water concentration, which manipulates viscosity of hydrogels, hydrogen bonding between polymers, polymer assembly manner, and thus the thickness of as-prepared carbon nanosheets. The enhanced interfacial properties of U-PCNS endow lithium–sulfur cathodes with excellent rate capability at 0.2C, outstanding cycle life over 1000 cycles, and an area-specific capacity up to 4.02 mAh cm–2.
Electrocatalytic water splitting is an effective strategy, which can convert intermittent energy such as wind energy and solar energy into renewable and sustainable hydrogen energy. Global freshwater ...resources are extremely scarce. Compared with freshwater, seawater is a rich and sustainable resource, and it has attracted more and more attention in electrocatalysis. However, the oxygen evolution reaction (OER) is a four‐electron transfer process, which leads to slow reaction kinetics. Moreover, the presence of various elements in seawater and their interference to electrochemistry make the OER in seawater extremely challenging. Herein, the latest progress in the development of transition metal‐based OER electrocatalytic materials for seawater is reviewed by hydroxides, oxides, chalcogenides, phosphides, and nitrides. Focus is made on how to eliminate competitive reaction chlorine evolution reaction of OER in electrolytic seawater. The recent research advances of OER catalyst for selective electrolysis seawater are summarized from the aspects of structure design, mechanism understanding, and performance enhancement strategy. Finally, the challenges, prospects, and research directions of seawater electrocatalysis for OER are introduced.
The latest research progress of OER catalysts for selective electrolysis of seawater is summarized from the aspects of structural design, mechanism understanding, and performance improvement strategies of transition metal compounds such as hydroxides, oxides, chalcogenides, phosphides, and nitrides.
In article number 2002432, Zhixin Wan, Bin Xi, and co‐workers find that atomic layer deposition (ALD) of CoN preferentially grows on the defects of sulfur‐doped carbon nanofiber/Co1‐xS matrix and ...modulates its surface/interface to produce an active and stable cobalt catalyst for overall water splitting. The strong electronic coupling between Co1‐xS and ALD CoN is found to play an important role for such performance.
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