Based on an introduction of the structural characteristics of single-crystal Ni-rich ternary cathode material, the common preparation techniques of such material are summarized. Besides, the main strategies for improving the performance of this material in recent years are also discussed, which can provide a reference for large-scale production of such high-performance single-crystal Ni-rich ternary cathode material.

An argyrodite-type sulfide solid electrolyte Li₆PS₅Cl (LPSC) was solid-phase synthesized by adopting high energy ball milling in combination with heat treatment. It is found that prolonging ball milling time is conducive to crushing, mixing, grain refinement and amorphization reaction process of raw material powder; increasing sintering temperature is beneficial to the formation of a single pure phase, but too high temperature for sintering can make electrolyte melted and decomposed, leading to destroyed crystal structure. It is found that after 10 hours of ball milling and 8 hours of sintering at 550 ℃, the synthesized sulfide solid electrolyte exhibits higher ionic conductivity, reaching 3.57×10^-3S/cm.

With tetraethyl orthosilicate as silicon source and cetyltrimethylammonium bromide (CTAB) as a surfactant and pore-forming agent, a carbon-coated mesoporous hollow silicon oxide as anode material was synthesized by adopting the modified stöber method and carbonthermal reduction. The results show that different volume ratio of ethanol to water can bring important impact to the particle size, morphology and performance of SiO_x nanospheres. With ethanol and water in a low volume ratio, the obtained nanomaterial has a low sphericity and becomes oval; as the ratio increases, the nanomaterial becomes larger in size; with ethanol and water in a ratio of 0.45, the obtained SiO_x nanospheres are around 300 mm in size. The button batteries assembled with such nanospheres deliver a reversible specific capacity of 813 mAh/g after 200 cycles at a current density of 100 mA/g, and 704 mAh/g after 1 200 cycles at 500 mA/g, retaining 82% of this capacity, with a capacity attenuation rate of 0.015% after each cycle.

A review of comprehensive recycling technologies for graphite anodes in spent lithium-ion batteries is presented, including hydrometallurgical process, a combination of pyrometallurgical and hydrometallurgical process, as well as mechanical recycling. And then, an in-depth analysis of advantages and disadvantages of each technology is also presented. It is particularly pointed out that there are various recycling technologies, but the development of an efficient and environmentally-friendly closed-circuit recycling process still faces challenges. The recycling approaches of graphite anodes in spent lithium-ion batteries are discussed in details, such as usage as anodes of rechargeable batteries, or for preparation of graphene. The research direction in the future is also forecasted aiming to provide theoretical and technical support for reutilization of graphite anodes in spent lithium-ion batteries with high-value added. It is suggested that research should focus on developing a simple, efficient and clean closed-circuit recycling processes to improve the recovery rate and purity of graphite anode materials while reducing environmental pollution. The research hotspots in the future should include lattice reconstruction and repairing technologies for graphite anode materials, as well as exploration of new applications of graphite anode materials in the fields of energy storage materials, catalysts, adsorbents among others.

Flash flotation technique was introduced to an experiment to recover crystalline graphite. The influence of impeller speed, superficial aeration rate and foam layer thickness on the flash flotation indices of graphite was investigated. The results show that flotation with impeller speed of 750 r/min, superficial aeration rate of 0.3 m³/(m²·min) and foam layer thickness of 20 mm can bring a better flotation performance of graphite. According to the particle size analysis and microscopic observation analysis of concentrate, the flash flotation displays good recovery of the graphite in a particle size range of 0.074-0.180 mm, which is dominated by flake graphite monomer and rich intergrowth. As the flash flotation technique favors the collection of useful minerals from the classification underflow in advance, the probability of overgrinding can be reduced and the flake morphology can be therewith reserved. Therefore, flash flotation technique is expected to be commercially applied in the flotation recovery of crystalline graphite.

Aiming at obvious elastic-plastic deformation of diamond drill bits in the process of drilling marine gas hydrate, a modeling approach that is suitable for the core drilling process of drill bits was proposed based on the Hertz theory. Firstly, the rock-breaking mechanism was analyzed for marine gas hydrates from elastic deformation to elasticplastic deformation during the drilling process under sea, and the drilling pressure and cutting force of single diamond particle on the diamond bit during the drilling process were calculated. Secondly, according to the stress condition of a single diamond particle, the theoretical relationships between drilling pressure and torque on the whole bit and other drilling parameters were obtained, and a mechanical model was established for the diamond drilling bit. Finally, a relationship curve between the saturation of marine gas hydrate and the torque and drilling pressure was obtained based on analysis. An at-sea testing by adopting such method has successfully taken some samples of marine gas hydrate, which has verified the feasibility of this method. This research provides a theoretical reference for the design of drill bit parameters and optimization of efficient deep-sea core drilling operation.

In order to identify the feasibility of preparing alkaline pellets with low-quality magnesium-containing flux, experiments on pelletizing, preheating and roasting were carried out. Three kinds of magnesium-containing flux from Wulongquan Mine of WISCO Resources Group Co., Ltd., including interbedded dolomite, light-burnt material and lightburnt dolomite, were taken for pelletizing, and then effects of different magnesia flux and the adding amount on pelleting, as well as following preheating and roasting processes of alkaline pellet were all explored. The results show that the green ball prepared with the flux of interbedded dolomite presents superior performance. It is found that with alkalinity of 0.8, the green ball prepared with two different blending schemes have drop number of 4.1 and 6.6 respectively from height of 0.5 m, and compressive strength of 20.3 N/pellet and 22.3 N/pellet respectively. By increasing the addition of magnesia flux in two blending schemes, both preheated balls and roasted balls have their strength decreased after an initial improvement. With alkalinity between 0.6 and 0.8, the prepared pellet can have compressive strength of 2 620 N/pellet and 2 963 N/pellet respectively after preheating and roasting process. It is recommended that with interbedded dolomite and light-burnt material as magnesia flux, the alkaline magnesium-containing pellet prepared with alkalinity of 0.6-0.8 can meet industrial requirements.

In order to explore the formation mechanism of landslides and reveal the development process of landslides, Mayang Miao Autonomous County in Hunan Province was taken as an example, and landslide analysis was conducted for red beds area in Hunan Province based on susceptibility to the selected factors causing disasters, including elevation, slope, terrain ruggedness index (TRI), stratum lithology and distance away from faults, among others. It is found that landslide occurrence is well correlated with several factors, with susceptibility to each factors in the following descending order: type of land use>elevation > TRI > normalized difference vegetation index (NDVI) > distance away from roads > slope > stratum lithology > distance away from rivers > average rainfall during recent several years > distance away from fault, and the corresponding factors with high sensitivity are listed as follows: land used for buildings, elevation [101 m, 1 394 m), TRI[47 m, 74 m) and NDVI[0.30, 0.43).

A kind of hydrogen storage alloy of La_0.7R_0.1Mg_0.2Ni_3.35Al_0.15 (R=La/Nd/Sm) was synthesized with induction melting method, and the effect of La substituted with rare earth element Nd/Sm on the phase structure, microstructure, and electrochemical performance of the hydrogen storage alloy was explored. The results show that the substitution of Nd or Sm for La doesn't change the phase composition of the hydrogen storage alloy, which is still composed of LaNi₅, (LaMg)₂Ni₇, and (LaMg)₅Ni₁₉ phases, but leads to higher abundance of LaNi₅ and (LaMg)₅Ni₁₉ phases, and lower abundance of (LaMg)₂Ni₇ phase in the hydrogen storage alloy. The hydrogen storage alloy, with La, Nd and Sm as R, deliver the maximum discharge capacities of 377 mAh/g, 382 mAh/g and 376 mAh/g, respectively, after the second charge-discharge cycle. With La substituted with Nd or Sm, the hydrogen storage alloy has its high-rate discharge capacity, the charge retention rate after 24 hours, and capacity retention rate after 100 cycles all improved to some extent, among which the hydrogen storage alloy with Nd as R is the best in all corresponding performance. Moreover, the substitution of La with Nd or Sm can make the hydrogen storage alloy with higher exchange current density and higher coefficient of hydrogen diffusion. Its high-rate discharge performance, exchange current density and hydrogen diffusion coefficient are all in in the same trend, indicating that high-rate discharge performance of the hydrogen storage depends on both exchange current density and hydrogen diffusion coefficient.

With silicon material (BFSi) extracted from blast furnace slag as silicon source and polyacrylonitrile (PAN) as carbon source, a kind of silicon-carbon anode material for lithium-ion batteries was synthesized. And the influence of ratio of silicon to polyacrylonitrile on the BFSi@C material was investigated. Results show that BFSi@C synthesized with BFSi and PAN in a mass ratio of 3∶1 delivers an initial charge capacity of 1 884.99 mAh/g at a current density of 0.5 A/g. After 100 cycles, it still delivers a specific charge capacity of 1 509.32 mAh/g, with a capacity retention rate of 80.07%. Moreover, it presents excellent rate performance at high current densities. Compared with commercial silicon materials, BFSi@C demonstrates higher cycle capacity and superior rate performance, delivering a specific capacity up to 538.31 mAh/g at a current density of 5 A/g.