Olivine LiFePO₄ is one of the most widely used cathode materials for lithium-ion batteries,with characteristics of low cost,high safety,environment-friendly,long cycle life and stable operating voltage.In recent years,with the breakthrough of CTP technology and blade battery technology,its commercialization progress has been greatly improved.However,LiFePO₄ has the defects of poor electronic conductivity and low ion diffusion coefficient,which seriously limits the electrochemical capacity of lithium-ion battery.It is of great significance to study on the preparation process and performance enhancement of LiFePO₄. In this paper,the differences of performance and development status of LiFePO₄ and other cathode materials for lithium-ion batteries were compared.The modification methods of preparation and strengthening of LiFePO₄ cathode materials and related research progress and challenges were systematically summarized,and the future development direction and research ideas were put forward.

Solar driven photocatalysis is an effective method to prepare clean fuels，degrade pollutants and convert high value-added products to solve the problems of energy shortage and environmental pollution.With the further study of metal halide perovskite，researchers have successfully developed a series of synthesis methods which can prepare perovskite quantum dots with precise composition and morphology control，good product uniformity and high crystallinity，so that perovskite quantum dots can be applied to the field of photocatalysis.The synthesis methods of metal halide perovskite quantum dots by thermal injection，ligand-assisted reprecipitation，solvothermal method and microwave assisted method were reviewed，and the research progress of metal halide perovskite in the aspects of photocatalytic hydrogen evolution，photocatalytic reduction of CO₂，photocatalytic synthesis of organic matter and photocatalytic degradation of organic matter were discussed.Finally，the development prospect of metal halide perovskite photocatalyst was prospected.

Hydrogen energy is recognized as an ideal green energy.The development and utilization of hydrogen energy can not only get rid of the long-term dependence on traditional fossil energy,but also solve the problems of energy shortage and environmental pollution.The low-cost,efficient and environmentally friendly production of hydrogen is conducive to the im-plementation of China′s energy structure transformation and sustainable development strategy.Among them,the use of renew-able biomass-derived compounds for hydrogen production has attracted more and more attention.From the perspective of chemistry and energy,the research on hydrogen production by reforming with the three major biomass-derived compounds of bio-alcohols,phenols and acids as raw materials at home and abroad was reviewed and commented,the reaction mechanism of hydrogen production from the reforming of these biomass-derived compounds was analyzed,and the effect of catalysts and carriers on hydrogen production from the reforming and the problems faced by the catalytic system and the improvement methods were centrally elaborated.In view of the current research trend of hydrogen production,which focused on catalyst modification,carrier optimization and process improvement,the future research direction of developing new carriers and additives,enriching catalyst systems and integrating various hydrogen production processes were proposed.

Metal-organic frameworks（MOFs） have attracted extensive attention due to their large specific surface areas,controllable pore structures and abundant active sites.Recently,MOFs-based materials were widely used in the field of ener-gy storage and conversion; however,the low stability and low conductivity of most MOFs-based materials limit their practical applications.By modifying MOFs based materials,such as the use of high conjugated organic ligands could increase the stabi-lity of MOFs materials or MOFs derivatives could improve their redox active sites and electrical conductivity,thus,the elec-trochemical performances of MOFs-based electrode materials can be improved.In this review,we mainly introduce progress of the pristine MOFs and MOFs derivatives including carbon materials,metal oxides,metal sulfides,metal hydroxide and metal phosphide, etc.in the field of supercapacitor.The results show that multi-metallic MOFs or their derivatives are beneficial to improve the electrochemical performances,the conductive MOFs and the carbon materials,which are derived from MOFs materials,are beneficial to improve the electrical conductivity of electrode materials.Finally, the outlook and prospect of MOFs-based electrode materials for electrochemical energy storage are also point out.The morphology, components and conductivity of the electrode materials are research develop direction in the future work.

The greenhouse effect caused by excessive carbon dioxide（CO₂） emissions makes global warming increasingly ur-gent,under the background of “double carbon”,how to utilize CO₂ is of particular importance.The photocatalytic reduction of CO₂ to produce chemicals and fuels is a promising way to solve both energy crisis and environmental problems.Non-metal semiconductor,polymeric carbon nitride（PCN） has attracted much attention in the field of photocatalysis due to its visible light response,high chemical stability,easy preparation and low cost.However,PCN prepared by the traditional thermal polymerization method suffers from small specific surface area,serious electron-hole recombination as well as limited visible light response range.The reaction mechanism of CO₂ photoreduction and the structure of PCN were introduced.The preparation methods of PCN and the modification methods for improved photocatalytic performance were summarized,including morpho-logy control,heteroatom doping,defect engineering and heterojunction construction.Finally,the problems existing in the research of PCN materials in CO₂ photoreduction were analyzed,and the future development direction was prospected.

Aqueous zinc ion battery is a novel battery system with the characters of low price,safety,environmental friendly,as well as high power density,which has good application value and development prospect in many fields such as energy stor-age.The progress of the basic research and industrialization of aqueous zinc ion battery was summarized from the aspects of cathodes,zinc anode,and electrolyte,and the industrial development of manganese dioxide cathode materials,battery assem-bly and application technologies were introduced.The feasibility and difficulties for future research and industrial development were highlighted.Three main issues that needed to be urgently solved were proposed.Firstly,the energy storage mechanism of aqueous zinc ion battery system was still needed in-depth study,which was important to guide the design of high performance cathode and anode materials.Secondly,the lack of key links in the industrial chain such as high-purity manganese dioxide cathode material,corrosion-resistant collector and puncture resistant diaphragm restricted the development of commercial batteries.Finally,from laboratory to pilot test and large-scale amplification,the battery performance was significantly reduced, and the systematic electrode preparation and battery assembly process was still needed systematic research.

Fly ash is the solid waste after the combustion of pulverized coal in coal-fired power plants.Its increasing accumu-lation not only occupies a large amount of land resources,but also destroys the original natural environment and causes seri-ous pollution.In recent years,the treatment and resource utilization of fly ash has received widespread attention. Improving the comprehensive utilization of fly ash is the key to stimulate the potential activity of fly ash.The physical activity and chemi-cal activity sources of fly ash were introduced,and the physical activation,hydrothermal activation and chemical activation technology and activation mechanism of fly ash activity were reviewed,which provided reference for the subsequent activation research and large-scale utilization of fly ash.The fly ash could be activated by using various methods,however,when selected the sole activation method,it needed high investment and suffered low activation degree.In the future,fly ash excitation tech-nology would develop in the direction of multiple means.

A large amount of by-product gypsum is produced in the process of industrial production,such as electric power,iron and steel,phosphate fertilizer,etc.If it cannot be properly treated and put it aside in large quantities,it will not only cause environmental pollution but also lead to waste resources.The harmless,comprehensive and high-quality utilization of by-pro-duct gypsum has become a topical focus in industrial development.The application and technical development status of desul-furization gypsum and phosphogypsum in cement,building materials,agriculture and chemical industry were summarized,and the suggestions for the resource utilization of industrial gypsum in the future were put forward.In this paper,it was pointed out that industrial routes such as preparing sulphuric acid co-production cement,calcium ferrite and conversion of ammonium to sulphuric acid by industrial gypsum were feasible,which would expect to realize the large-scale utilization of desulphuriza-tion gypsum and phosphogypsum.

MnO₂ was synthesized by hydrothermal method using sodium dodecyl benzene sulfonate as templates.The effect of hydrothermal temperature on the structure of MnO₂ and decolorization properties of dyes and the effect of product dosage and pH of dye solution on decolorization performance of dyes by MnO₂ were studied.The results showed that when the hydro-thermal temperature was 110 ℃,2~8 μm spherical γ-MnO₂ were obtained,which had the best decolorization rate on methylene blue（MB） and Rhodamine B（RhB）.When the adding amount of MnO₂ was 6 g/L,the decolorization rates of 50 mg/L MB and RhB reached 86.95% and 76.07%,respectively.The addition of strong acid and strong alkali had a significant increase in the decolorization rate of MB.The adsorption process of MnO₂ on MB was conformed to the Langmuir and Freundlich isothermal model.The addition of strong acid had a significant increase in the decolorization rate of RhB.The adsorption pro-cess of MnO₂ on RhB conformed to the Freundlich isothermal model.The product was recyclable,and the adsorption amount of MB and RhB only decreased with 1.08 mg/g and 2.66 mg/g after three cyclic adsorption,respectively.

Lithium resources are important national strategic resources,which are widely used in many fields such as new energy vehicles,electronic products,and energy storage.China is rich in lithium resources.Among them,salt lake brine lithium resources are mainly distributed in Qinghai and Tibet.However,due to factors such as the low grade of salt lake brine itself,low extraction efficiency of lithium salt and limited production capacity,it has not been effectively developed,resulting in a serious dependence on foreign lithium products.Therefore,in order to ensure the continuous and safe supply of lithium resources in China,it is of great significance to break through the lithium extraction technology from salt lakes and explore more green,efficient and low-cost extraction technologies for the utilization of lithium resources in salt lake brines.The general situation of lithium resources in salt lakes,the characteristics of salt lake brine,and the latest research progress of efficient separation and extraction of lithium resources were systematically introduced.Finally,the research focus of lithium resources separation and extraction technology was prospected.

As a green hydrogen production technology, electrolyzed water splitting has received lots of attention.Design and development of high-efficient and low-cost electrocatalysts,which are suitable for full pH（pH=0-14) media,can reduce ener-gy consumption,simplify device construction and optimize production process.MoS₂ has been considered as one of the pro-mising materials for electrochemical hydrogen evolution,due to its tunable electronic structure and the most suitable thermo-dynamic activity except for precious metals.The current research progress of MoS₂-based pH-universal catalysts for electro-chemical hydrogen evolution reaction was reviewed,such as modulating physical property of intrinsic MoS₂,surface engineer-ing with atom doping,and interface engineering.The corresponding catalytic mechanism was clarified.It was revealed that preparation of catalysts with both hydrogen evolution activity and stability at high current density in all-pH range would be the tendency of electrocatalytic materials.It was also proposed that activation of inert basal plane for multi-level structural MoS₂ materials,enhancement of the whole electroconductivity,anchor of single atoms precisely,and encapsulation of active materials with porous carbon would be the fundamental strategies for designing efficient pH-universal catalysts.

The current development status of membrane technology for CO₂ removal from natural gas was reviewed.Firstly，the technical characteristics and application situations of various processes for removing CO₂ from natural gas were compared.Compared with other separation methods，the membrane separation method has the advantages of less investment，small footprint，and low energy consumption.The principle of membrane separation，membrane materials，development status of membrane modules，and technical units of membrane technology to remove CO₂ from natural gas were introduced.The process technology unit was further divided into pretreatment unit and membrane separation unit：the pretreatment unit was selected to different removal methods to combine according to the components of the produced raw material gas；the raw material gas was entered the membrane separation unit after passing through the pretreatment unit.According to the actual working conditions，considering the hydrocarbon recovery rate，land occupation，energy consumption，investment and other factors，the membrane decarbonization separation process was reasonably designed.Then，the domestic and foreign application cases for the removal of CO₂ from natural gas by membrane methods were introduced.At present，there were many application cases of foreign membrane methods to remove CO₂ from natural gas，while there were few domestic application cases.Therefore，it was necessary to increase the domestic membrane method to remove CO₂ from natural gas industrial applications.Finally，the development direction of CO₂ removal technology by natural gas membrane method was prospected.The research and development of membrane materials with independent intellectual property rights and maintaining high performance and long?term stability under actual complex working conditions is the focus of future membrane separation technology development.A coupled integrated combined process was that combining two or more single CO₂ removal technologies，such as membrane separation+chemical absorption，membrane separation+temperature swing adsorption，etc.This coupled integrated combined process would provide new directions for the future decarbonization process technological developments.

China will peak carbon before 2030 and achieve carbon neutrality by 2060,which is our solemn commitment to the international community.Materials are an important substantial foundation for developing carbon reduction technology.By introducing the latest research progress of multiscale rare earth new materials in energy storage,exhaust gas/tail gas catalysis, electrocatalysis and permanent magnet motor,the role of multiscale rare earth new materials in tackling the dual carbon goal was analyzed.Rare earth is an important“industrial vitamin”.The unique role of rare earth in functional materials at the scales of atomic ion,nano/micron and bulk was emphatically introduced.In quantum materials,the latest research progress of rare earth strong correlation solid electrolytes,rare earth superconducting materials and rare earth damping materials also were analysed.It is hoped that the development of new rare earth functional materials will play a role in reducing carbon emissions.

Inorganic silica aerogels have broad application potential in energy saving and carbon reduction in aerospace,aviation,industrial and construction fields due to their ultra-low thermal conductivity,nonflammability of class A,low mo-isture absorption rate and light weight.However,poor mechanical property and high preparation cost limit the development and application of silica aerogels.The research progress of preparation technology of silica aerogel insulation materials was introduced.The application forms of silica aerogels in building field（such as super light aerogel foam concrete,super high performance aerogel insulation board,ultra-low heat transfer coefficient aerogel energy-saving glass） were reviewed,and the development trend of silica aerogels in building energy conservation was prospected.In response to the goal of carbon neutral development,with the development and cost reduction of aerogel preparation technology,silica aerogel insulation materials would be widely applied in building insulation,and at the same time,more functional requirements were put forward for their performance.Therefore,more systematic basic research and engineering application technology research are needed for silica aerogel materials to promote energy conservation,carbon reduction and sustainable development in the field of construction.

China′s comprehensive utilization of phosphogypsum has ranked the world′s leading level,and the comprehensive utilization approaches are diversified, but there are also some problems to be solved,such as unclear understanding of phospho-gypsum,lack of innovation motivation,lack of coordination between upstream and downstream industries and so on.The im-plementation of “carbon peak and neutrality goals” strategy is both an opportunity and a challenge for the comprehensive utiliza-tion of phosphogypsum resources. Based on this,the current situation of comprehensive utilization of phosphogypsum resources at home and abroad was introduced, the production and utilization of phosphogypsum in China were mainly described.With the improvement of China′s phosphate fertilizer production process, technology and management level,the quality of phosphogypsum is gradually improved,the amount of phosphogypsum by-product of phosphate fertilizer is gradually reduced,and the comprehensive utilization of phosphogypsum resources and the level of utilization will continue to improve.

Lithium ion battery（LIB） is considered as the best choice for power battery because of its advantages such as high working voltage and energy density,long cycle life,no memory effect and small self-discharge.Lithium manganese phosphate（LiMnPO₄,LMP） is a promising cathode material for lithium-ion batteries,which has good thermal stability and high operating voltage,but still need to overcome some technical bottlenecks such as insufficient conductivity and poor cycling stability.In order to improve the electrochemical performance of LMP,LMP with uniform particle size and controllable morphology can be prepared by liquid phase method,which can effectively shorten the transmission distance of Li⁺,fully alleviate the problem of excessive stress at the phase interface in the process of charging and discharging.It is conducive to improve the rate perfor-mance and cyclic stability.Bulk phase doping has unique advantages in improving intrinsic conductivity,Li⁺ diffusion coefficient and stabilizing material structure,among which Fe doping has important research significance.In addition,improving the synthesis process to prepare composite cathode materials with specific structure and specific element distribution has signi-ficant advantages to improve the comprehensive performance of the materials.The research progress of the modification of LMP in the aspects of material nanocrity,ion doping and material composite in recent years was summarized systematically.It was considered that the development of nano-LiFe_xMn_1-xPO₄（0<x<0.5） composites would become a new development trend.

As an ideal secondary energy,hydrogen energy has the characteristics of high energy density,clean and pollution-free,and will play an extremely important role in the process of energy transition.Hydrogen production by water electrolysis is considered as the most promising green process for obtaining hydrogen energy,while high-efficiency electrocatalysts are the key to restrict the development of hydrogen production by water electrolysis.Noble metal catalysts have excellent electroca-talytic performance,but their promotion and application are severely restricted by the cost and reserves.Therefore,the devel-opment of low-cost and high-activity non-noble metal catalysts has gradually become a research hotspot.In order to improve the electrocatalytic performance of non-noble metal catalysts,a series of modification and optimization are needed.The research progress on the modification of non-noble metal catalysts for water electrolysis at home and abroad in recent years was reviewed.The modification methods of geometric construction（one-dimensional,two-dimensional,three-dimensional structure）and electronic regulation（composition optimization,crystal plane control,defect construction,heteroatom doping,etc.） were introduced in detail.The development direction of non-noble metal catalyst modification in future was also prospected.

With the rapid development of strategic emerging industries such as new energy and new materials,the demand for mineral resources in emerging industries such as unconventional energy,rare earth elements and lithium has become increas-ingly prominent.Lithium is one of the scarce emerging mineral resources in the “National Mineral Resources Planning 2016-2020”.In addition,the international attention to the new energy vehicle industry in recent years has led to an increase in the demand for lithium resources year by year.Although China has a certain advantage in the amount of lithium resources,the in-dustrial development layout is not reasonable,resource development can not keep up with the requirements of industrial de-velopment,and most of the basic lithium salt depends on the import of raw materials,so the development and utilization ca-pacity of lithium resources in China needs to be strengthened.The overall occurrence of three types of lithium resources in China was summarized, including salt lake brine type,hard rock type and deep underground brine type,and the research status and related mining technology of each type of lithium resources were analyzed.At the same time, combining the present situation of supply and demand of lithium resources in China,the production of various types of lithium resources supply situation was analyzed.It was pointed out that the current production of Chinese salt lake brine type lithium resources was short in China, hard rock type lithium supply was high external dependency,and deep underground brine was expected to become the future lithium resources powerful supplement.It was suggested to strengthen the investigation of deep underground brine type lithium resources evaluation and the study of comprehensive utilization of resources.

Lithium ion sieves（manganese and titanium series） show high adsorption selectivity for lithium ion in salt lake brine with high Mg/Li ratio（mass ratio）.The lithium extraction mechanism of spinel structure lithium ion sieve mainly includes redox mechanism，ion exchange mechanism and composite mechanism，while the layered structure lithium ion sieve is mainly realized by simple ion exchange between Li⁺ and H⁺.The preparation process of lithium ion sieve is simple.First，solid phase combustion，microwave combustion or sol-gel process，hydrothermal method，coprecipitation method and molten salt synthesis method are used to prepare precursors，and then the Li⁺ in the corresponding precursor can be replaced by H⁺.The prepared lithium ion sieve can be used to extract lithium from liquid lithium resources such as salt lake brine and seawater with large reserves and low grade.In recent years，the research is mainly focused on titanium lithium ion sieve with higher structural stability，however，further studies are needed to further improve the structural stability and realize engineering application.

The recent research on modified lithium iron phosphate（LiFePO₄） materials as lithium-ion electronic cathode materials was reviewed.Although LiFePO₄ were considered to be the most promising cathode materials for lithium-ion power batteries due to their good stability，high safety and environmental friendliness，their inherent low electronic conductivity and lithium-ion diffusion coefficient deteriorated their electrochemical performance.The study on modification to improve their electrochemical performance was reviewed in this paper.The effects of four modification strategies including elemental doping，surface carbon coating，particle nanosizing and materials compositing on the electrochemical performance of LiFePO₄ were analyzed.Then，the advantages and disadvantages of these four modification strategies were discussed.The analysis showed that the four modification strategies could effectively improve the Li-ion diffusion kinetics and electronic conductivity，but the surface carbon coating and particle nanosizing would conversely reduce the tap density of the materials，resulting in low energy density.Finally，the research direction to solve the existing problems was proposed that it would be a feasible method to develop a modification strategy with coexistence of battery and capacitive properties.