Research progress on ZnSe and ZnTe anodes for rechargeable batteries

Ultraviolet-Visible-near infrared induced photocatalytic H2 evolution over S-scheme Cu2-xSe/ZnSe heterojunction with surface plasma effects

Localized surface plasmon resonance (LSPR) effect plays a crucial role in the field of solar energy utilization. In this work, we successfully prepared a Cu2-xSe/ZnSe S-scheme heterojunction with a broad-spectrum response using the hot-injection and low-temperature water bath method. Importantly, we demonstrated that the photothermal effect induced by the LSPR of nonstoichiometric Cu2-xSe can significantly improve the slow kinetics of water splitting, resulting in an apparent activation energy reduction from 50.1 to 28.7 kJ·mol-1. This improvement is responsible for achieving the highest photocatalytic H2 evolution rate of 63.6 mmol·g-1·h-1 over 2.7 % Cu2-xSe/ZnSe under the wavelength ranged from 200 to 2500 nm, which is 3.4 and 5.6 times higher than that of ZnSe and Cu2-xSe, respectively. Furthermore, the composite exhibits a remarkable H2 production rate of 0.108 mmol·g-1·h-1 under near-infrared spectroscopy (800<λ<2500 nm), while ZnSe shows limited capability in H2 releasing. Additionally, Cu2-xSe/ZnSe demonstrates distinct photocurrent response when λ > 800 nm. The enhanced performance in H2 evolution can be attributed to the synergistic effect of LSPR-induced light absorption and S-scheme heterojunction, which not only expands the light absorption range to the near-infrared region but also facilitates hot electron injection, charge carrier separation and transfer, leading to a faster surface reaction kinetics. This study provides an effective approach for designing a broad-spectrum light responsive non-precious metal-based photothermal-assisted photocatalytic system.

Rational design of a setaria-like NiTe2/MoS2 semi-coherent heterogeneous interface for enhancing diffusion kinetics in potassium-ion batteries

Constructing unique heterostructures is a highly effective approach for enhancing the K+ storage capability of transition metal selenides. Such structures generate internal electric fields that significantly reduce the charge transfer activation energy. However, achieving a flawless interfacial region that maintains the optimal energy level gradient and degree of lattice matching remains a considerable challenge. In this study, we synthesised Setaria-like NiTe2/MoS2@C heterogeneous interfaces at which three-dimensional MoS2 nanosheets are evenly embedded in NiTe2 nanorods to form stabilised heterojunctions. The NiTe2/MoS2 heterojunctions display distinctive electronic configurations and several active sites owing to their low lattice misfits (δ = 13 %), strong electric fields, and uniform carbon shells. A NiTe2/MoS2@C anode in a potassium-ion battery (KIB) exhibited an impressive reversible capacity of 125.8 mAh/g after 1000 cycles at a rate of 500 mA g-1 and a stable reversible capacity of 111.7 mAh/g even after 3000 cycles at 1000 mA g-1. Even the NiTe2/MoS2@C//perylene tetracarboxylic dianhydride full battery configuration maintained a significant reversible capacity of 92.4 mAh/g after 100 cycles at 200 mA g-1, highlighting its considerable potential for application in KIBs. Calculations further revealed that the well-designed NiTe2/MoS2 heterojunction significantly promotes K+ ion diffusion.

Magnetic field effects on the crystal structure, morphology, energy gap, and magnetic properties of manganese selenide nanoparticles synthesized by hydrothermal method

In this study, we synthesized manganese selenide under magnetic fields ranging from 0 to 800 gauss and investigated its optical, electrical, and magnetic properties. In the absence of a magnetic field, we observed the formation of MnSe nanorods. As the field strength increased, impurities arose. In the 250 G range, two rock salt structures emerged, altering the morphology from nanorods to cubes. Beyond 250 G, MnSe2 formed, returning to a nanorod morphology. Also, with the increase of the magnetic field, the energy gap of the synthesized compounds increased. To measure the electrical properties of the samples, the synthesized powders were compressed under the same pressure for a certain period of time, and it was observed that the synthesized samples showed insulating behavior in the presence of a magnetic field. For this reason, we performed current-voltage, resistance-temperature, and current-temperature analyses on the synthesized sample, at a constant voltage of 5 eV in the absence of a magnetic field.

Facile Preparation of the ZnSe/Ag2Se Binary Heterojunction for Photocatalytic Antibacterial Efficiency

In a novel approach that capitalized on the differential solubility product (Ksp) of ZnSe and Ag2Se, a unique ZnSe/Ag2Se binary heterostructure was efficiently synthesized in situ. ZnSe/Ag2Se exhibited excellent antimicrobial efficiency under visible light. Incorporating Ag2Se into ZnSe significantly enhanced the photoelectric performance of the catalyst, greatly accelerating the separation of the photogenerated electrons in the system. Active species removal experiments determined that ·O2- and H2O2 played crucial roles in photocatalytic antibacterial efficiency. Further investigation into the levels of cellular membrane peroxidation, bacterial morphology, and intracellular contents concentration revealed that during the photocatalytic antimicrobial process, reactive oxygen species initially oxidize phospholipids in the cell membrane, leading to damage to the external structure of the cell and leakage of the intracellular contents, ultimately resulting in bacteria inactivation. The photocatalytic antimicrobial process of ZnSe/Ag2Se fundamentally deviates from conventional methods, offering new insights into efficient disinfection and photocatalytic antimicrobial mechanisms.

Enhanced Interfacial Magnetization is Responsible for the Negative Capacity Fading of Cobalt Ditelluride Anodes for Lithium Storage

In lithium-ion batteries (LIBs), the stabilized capacities of transition metal compound anodes usually exhibit higher values than their theoretical values due to the interfacial charge storage, the formation of reversible electrolyte-derived surface layer, or interfacial magnetization. But the effectively utilizing the mechanisms to achieve novel anodes is rarely explored. Herein, a novel nanosized cobalt ditelluride (CoTe₂ ) anodes with ultra-high capacity and long term stability is reported. Electrochemical tests show that the lithium storage capacity of the best sample reaches 1194.7 mA h g^-1 after 150 cycles at 0.12 A g^-1 , which increases by 57.8% compared to that after 20 cycles. In addition, the sample offers capacities of 546.6 and 492.1 mA h g^-1 at 0.6 and 1.8 A g^-1 , respectively. During cycles, CoTe₂ particles (average size 20 nm) are gradually pulverized into the smaller nanoparticles (<3 nm), making the magnetization more fully due to the larger contact area of Co/Li₂ Te interface, yielding an increased capacity. The negative capacity fading is observed, and verified by ex situ structural characterizations and in situ electrochemical measurements. The proposed strategy can be further extended to obtain other high-performance ferromagnetic metal based electrodes for energy storage applications.

Aluminium substitution in Sb2S3 nanorods enhances the stability of the microstructure and high-rate capability in the alloying regime

Alloy anodes, with twice the capacity of graphite, are promising for next-generation lithium-ion batteries (LIBs). However, poor rate-capability and cycling stability, mainly due to pulverization, have limited their application. By constraining the cutoff voltage to the alloying regime (1 V to 10 mV vs. Li/Li⁺), we show that Sb_1.9Al_0.1S₃ nanorods provide excellent electrochemical performance, with an initial capacity of ∼450 mA h g^-1 and excellent cycling stability with 63% retention (capacity ∼240 mA h g^-1 after 1000 cycles at 5C-rate), unlike 71.4 mA h g^-1 after 500 cycles observed in full-regime cycling. When conversion cycling is also involved the capacity degrades faster (<20% retention after 200 cycles) irrespective of Al doping. The contribution of alloy storage to total capacity is always larger than the conversion storage indicating the superiority of the former. The formation of crystalline Sb(Al) is noted in Sb_1.9Al_0.1S₃, unlike amorphous Sb in Sb₂S₃. Retention of the nanorod microstructure in Sb_1.9Al_0.1S₃ despite the volume expansion enhances the performance. On the contrary, the Sb₂S₃ nanorod electrode gets pulverized and the surface shows microcracks. Percolating Sb nanoparticles buffered by the Li₂S matrix and other polysulfides enhance the performance of the electrode. These studies pave the way for high-energy and high-power density LIBs with alloy anodes.

ZnTe/rGO Composite as the Fully Zinced Conversion-Type Cathodes for Aqueous Zinc Ion Batteries

Conversion-type cathodes for aqueous zinc ion batteries (ZIBs) can provide flat plateau slop and stable output potential, compared to general intercalation-type cathodes. The high volumetric capacity and stable output potential of Te make it a promising cathode for ZIBs, but sluggish kinetics and large volume change hinder its further application. To address these issues, we revisit fully zinced ZnTe and construct ZnTe/rGO composites as the new conversion-type cathode. The electrode undergoes a solid-to-solid conversion reaction and shows a stable output potential with ultra-flat discharge plateau slop of 0.09 V (Ah g^-1 )^-1 . When ZnTe is de-zinced and transformed to Te during charge process, it has a volume shrinkage which generates empty space in graphene matrix for latter volume expansion of Te. The graphene matrix also improves conductivity and reaction kinetics of the cathode. Due to the combination of pre-zincation of ZnTe, graphene matrix and the elimination of "shuttle effects" process, ZnTe/rGO electrode exhibits a high and stable capacity of 186 mAh g^-1 at 500 mA g^-1 after 300 cycling, with almost no decay after initial 10 cycles.