Research on Preparation and Electrochemical Performance of the High Compacted Density Ni-Co-Mn Ternary Cathode Materials

The high compacted density LiNi0.5-xCo0.2Mn0.3MgxO2 cathode material for lithium-ion batteries was synthesized by high temperature solid-state method, taking the Mg element as a doping element and the spherical Ni0.5Co0.2Mn0.3 (OH)2, Li2CO3 as raw materials. The effects of calcination temperature on the structure and properties of the products were investigated. The structure and morphology of cathode materials powder were analyzed by X-ray diffraction spectroscopy (XRD) and scanning electronmicroscopy (SEM). The electrochemical properties of the cathode materials were studied by charge-discharge test and cyclic properties test. The results show that LiNi0.4985Co0.2Mn0.3 Mg0.0015O2 cathode material prepared at calcination temperature 930°C has a good layered structure, and the compacted density of the electrode sheet is above 3.68 g/cm3. The discharge capacity retention rate is more than 97.5% after 100 cycles at a charge-discharge rate of 1C, displaying a good cyclic performance.

Regeneration of Al-doped LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode material by simulated hydrometallurgy leachate of spent lithium-ion batteries

A uniform Al-doped LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode material was prepared using a coprecipitation method to take advantage of the positive effect of Al on regenerated NCM(Ni,Co,Mn)cathode materials and ameliorate cumbersome and high-cost impurity removal processes during lithium-ion battery recycling.When the Al^(3+) content in the leachate was 1 at.%with respect to the total amount of transition metals(Ni,Co,and Mn),the produced Al-doped NCM cathode material increased concentrations of lattice oxygen and Ni^(2+).The initial specific capacity at 0.1C was 167.4 mA·h/g,with a capacity retention of 79.1%after 400 cycles at 1C.Further,this Al-doped sample showed improved rate performance and a smaller electrochemical impedance.These findings provide a reference for developing industrial processes to resynthesize cathode materials with improved electrochemical performance by incorporating Al^(3+) impurities produced during lithium-ion battery recycling.

Electrical Properties of GeTe-based Ternary Alloys

Ge_（50-x）Sb_xTe_（50） and Ge_（50-x）Bi_xTe_（50） ternary alloys were synthesized by vacuum melting at 1273 K with the starting materials of Ge, Bi, Sb, and Te. The lattice structures were analyzed based on X-ray diffraction patterns, which could all be indexed to R3m rhombic structure. Electrical properties measurements revealed that the Ge-Sb-Te ternary alloys were p-type semiconductors with high electrical conductivity of 4.5×10~5S？m^（-1） near room temperature. And the maximum electrical property was obtained at Ge_45Sb_5Te_50, with the power factor of 2.49×10^（-3）W？m^（-1）K^（-2） at 640 K. Due to the existence of secondary phases, the electrical conductivity of Ge-Bi-Te system was lower and Seebeck coefficient was higher comparing with those of Ge-Sb-Te system.

Synthesis of 2D ternary layered manganese phosphorous trichalcogenides towards ultraviolet photodetection

Manganese phosphorous selenium(MnPSe_(3)),as a representative of layered metal phosphorus trichalcogenides(MPTs),has gained significant attention due to its direct bandgap,high carrier mobility,large absorption coefficient,which indicate great potential in photoelectric application.Herein,high-quality two-dimensional(2D)MnPSe_(3) flakes were mechanically exfoliated from the corresponding bulk crystals synthesized by chemical vapor transport(CVT)methods.The systematic investigation was applied to the lattice vibrations of MnPSe_(3) via angle-resolved polarized Raman spectroscopy(ARPRS),and the Raman vibration modes were determined based on Raman selection rules and crystal symmetry.Impressively,the photodetectors based on 2D MnPSe_(3) flakes exhibit excellent photoresponse to the ultraviolet light with a responsivity up to 22.7 A W^(-1) and a detectivity of 2.4×10^(11) Jones.The high performance in the ultraviolet range signifies that 2D MnPSe_(3) is expected to be a powerful candidate for future ultraviolet photodetection.

Ultrathin 2D ternary Bi_(2)Te_(2)Se flakes for fast-response photodetectors with gate-tunable responsivity

Two-dimensional(2D) ternary materials have sprung up in a broad variety of optoelectronic applications due to their robust degree of freedom to design the physical properties of the materials through adjusting the stoichiometric ratio. However, the controlled growth of high-quality 2D ternary materials with good chemical stoichiometry remains challenging, which severely impedes their further development and future device applications. Herein, we synthesize ternary Bi_(2)Te_(2)Se(BTS) flakes with a thickness down to 4 nm and a lateral dimension about 60 μm by an atmospheric-pressure solid source thermal evaporation method on a mica substrate. The phonon vibration and electrical transportation of 2D BTS are respectively investigated by temperature-dependent Raman spectrum and conductivity measurements. Furthermore, the photodetector based on 2D BTS exhibits excellent performance with a high light on/off ratio of 1300(365 nm), a wide spectral response range from 365 to 980 nm, and an ultra-fast response speed up to 2 μs. In addition, its electrical and photoelectric properties can be modulated by the gate voltage, offering an improved infrared responsivity to 2.74 A W^(-1) and an on/off ratio of 2266 under 980 nm. This work introduces an effective approach to obtain 2D BTS flakes and demonstrates their excellent prospects in optoelectronics.

Dielectr ic barr ier discharge plasma-assisted modification of g-C_(3)N_(4)/Ag_(2)O/TiO_(2)-NRs composite enhanced photoelectrocatalytic activity

Dielectric barrier discharge(DBD)plasma applied as surface treatment technology was employed for the modification of Ag_(2)O and graphitic carbon nitride(g-C_(3)N_(4))powders.Subsequently,the pretreated powders were sequentially loaded onto TiO_(2)nanorods(TiO_(2)-NRs)via electro-deposition,followed by calcination at N_(2)atmosphere.The results indicated that at the optimal plasma discharge time of 5 min for modification of g-C_(3)N_(4)and Ag_(2)O,photocurrent density of ternary composite was 6 times to bare TiO_(2)-NRs under UV-visible light irradiation.Phenol was degraded by using DBD plasma-modified g-C_(3)N_(4)/Ag_(2)O/TiO_(2)-NRs electrode to analyze the photoelectrocatalytic performance.The removal rate of phenol for g-C_(3)N_(4)-5/Ag_(2)O-5/TiO_(2)-NRs electrode was about 3.07 times to that for TiO_(2)-NRs electrode.During active species scavengers'analysis,superoxide radicals and hydroxyl radicals were the main oxidation active species for pollutants degradation.A possible electron-hole separation and transfer mechanism of ternary composite with high photoelectrocatalytic performance was proposed.

An evaluation model of water-saving reconstruction projects based on resource value flows

Due to uncertainties in water supply,there is growing demand for water resource management in enterprises.In this study,we evaluated the effects of companies’water-saving reconstruction projects.We used Hina Advanced Materials Company as a case to construct an investment decision model to(1)calculate the internal and external costs of water resources based on circular economic value analysis theory,and(2)locate the level of water resources circulation.We adopted gray situation decision analysis to identify the typical problems that occur in water resource utilization.Moreover,we demonstrated optimization plans for different potential improvements,thereby providing guidance and references for water resource cost management and the comprehensive optimization of environmental benefits.We concluded that the circulation economic value analysis model can effectively display the flow and amount of value derived from water resource flows,thereby providing guidance and suggestions for optimizing water resource flows.