Hydrogen energy is the key support for China's "carbon neutrality" in 2060, and hydrogen preparation is the primary link in the four major links of the hydrogen energy industry chain, namely "production, storage, transmission, and use". The green and efficient production of hydrogen is the basis for the development of hydrogen energy. Anion exchange membrane water electrolysis (AEMWE), as an emerging "green hydrogen" technology, fully combines the advantages of alkaline water electrolysis and proton exchange membrane electrolysis technology, and is expected to become the most promising renewable energy hydrogen production technology. This paper briefly analyzes the principle and research status of AEMWE, and discusses in detail the research progress and development direction of key component of anion exchange membrane (AEM) water electrolyzer, including anion-exchange membrane, anode, cathode catalyst, bifunctional catalyst, ionomer, membrane electrodes, porous transport layer, bipolar plate, and electrolyte. Finally, in light of the current research status, the research and development direction of hydrogen production technology by AEMWE is envisioned.

The concept and origin of available energy—exergy were briefly introduced, theories about chemical exergy and cumulative exergy consumption and the significance of their application were presented in this paper. Problems existed in exergy analysis were poited out, and then the exergy input-output function was introduced to make exergy analysis on renewable energy, nonrenewable energy, recycling energy conversion and utilization. Conclusion was made that the depletion of global exergy could be relieved if only the proportion of renewable energy in the energy structure was increased and the exergy efficiency of conversion process was improved.

 In order to effectively control and manage the battery energy storage system (BESS), which plays more and more important roles in new energy integration and reducing environmental pollution, it is necessary to develop battery management system (BMS) to achieve a high performance of BESS. As an important parameter, the state of charge (SOC) of Li-ion battery has been researched widely nowadays, aiming to improve the estimation accuracy. LiFePO4 (LFP) battery  has a prospective value in various applications and its SOC is closely related to multiple factors. The relationships between temperature and several characteristics of battery, such as the open circuit voltage, charge-discharge efficiency, nominal capacity and self-discharge rate, are introduced in this paper. Based on the conclusions and summaries above, the temperature parameters were introduced to the SOC estimation model directly or indirectly in real time, the estimation accuracy of SOC would be improved significantly by considering the effects of temperature.

Improve the fast charging ability of li-ion battery is one of the important development directions of battery industry. However, fast charging battery often suffers from capacity and power performance degradation. Development of fast charging battery involving multiscale problem, needed to take into full consideration from atomic to battery level. In this paper, some of the key elements of developing fast charging battery were summarized based on the existing literatures. These elements include improving fast charging ability of batteries, improving the migration rate of lithium ions in the cathode material, speeding up the insertion rate of lithium ions into the anode material, increasing the ion conductivity of electrolyte, choosing the fast charge separator, enhancing the conductivity of ions and electrons in the electrode, and optimizing charge protocols.

Thermal energy storage (TES) using latent heat of phase change materials (PCMs) is an effective way for heat utilization. Currently, the most studied energy storage materials include inorganic systems (salts and hydrated salts) and organic compounds (paraffin, fatty acids, etc.). In this work, PCMs were classified and the basic characteristics of PCMs were summarized. In order to solve leakage problem of PCMs, the composite PCMs formed by adsorption of PCMs with porous materials and microencapsulation technology were introduced. The applications of PCMs in temperature control, heat storage, etc. were summarized; the current development of PCMs was summed up and its development trend was prospected.

In recent years, using organic solid waste as fuels has drawn increasing research attention. The pyrolysis technology of organic solid waste can produce various fuels or valuable by-products, which have a great potential to be used as a renewable energy source. However, due to a wide range of sources and different compositions, the effective pyrolysis products of organic solid waste can vary greatly when different pyrolysis technology and reaction conditions are adopted. In order to investigate the influence of pyrolysis temperature on the composition of pyrolysis gaseous products, this review summarizes the research status of the composition of pyrolysis gaseous products of different organic solid wastes, analyzes the effective utilization method of pyrolysis gas, so as to provide a reference for the energy utilization of pyrolysis gas in the future.

Organic Rankine Cycle (ORC) is considered as a promising technology for effective utilization of low-temperature energy. Large number of studies on the ORC system (including the working fluid, the expander, the heat exchanger, and optimization of system) have been carried out by the researchers. In this study, the working fluids selection for different type heat sources, characteristics of expanders, heat exchanger influences and system design optimization are discussed and summarized to provide some references for the utilization of the ORC system.

With virtues of high safety, long cycle life, environmental friendly and state of charge easy monitoring, vanadium flow battery has been considered as an effective technique for large scale energy storage. In this paper, the research and development background of energy storage, application effect of energy storage in the grid system and typical application projects of vanadium flow battery are analyzed and reported.

This paper reviews the current research status of high temperature vapor compression heat pumps on the aspects of new working fluids and system efficiency. For high temperature absorption heat pump, this paper discusses the present research on new circulation design, system control and simulation, parameter optimization and improving heat transfer efficiency. Finally, two kinds of heat pump steam generator newly developed are introduced regarding their operating principle and concept characteristics. According to the operating requirements of heat pump steam generator, the future research direction and the main technology problems are also concerned.

Lithium ion phosphate (LiFePO4) has been investigated as the mainstream cathode in lithium-ion power batteries because of its high safety, low cost and environment friendly. As an inactive but crucial component of the electrode, the binder has great impact on the electrochemical performances of lithium-ion batteries. In this paper, research progress of water soluble binders used in LiFePO4 cathode for lithium-ion batteries is reviewed, and the existing issues and potential challenges of present research are pointed out. Finally, the future development of water soluble binders is also prospected.

Based on its properties of strong scattering and low energy flux, the low-temperature heat can be easily obtained from solar radiation. Solar low-temperature heat utilization is the earliest solar energy conversion means known by humans and widely applied. In the future, it will remain to be the most important means of solar application, which can be used extensively and economically. The background and theories of several main technologies of low-temperature solar thermal conversion are introduced in this paper, such as solar thermal collection, solar space heating, solar drying, solar-assisted heat pump, solar air conditioning and low-temperature solar thermal power systems. Based on the research status of various existing techniques and social needs, the future development direction of this area is discussed. The research on the low-temperature solar thermal conversion in the University of Science and Technology of China is also presented in this paper.

Due to the huge reserve, wide spread, and renewability, lignocellulose has been chosen as the alternative energy resource for fossil fuels, such as coal, petroleum and nature gas. One important way for the utilization of lignocellulose is fuel ethanol. Cellulose, hemicellulose and lignin are the main components of lignocellulose. Their close association causes physical and chemical barriers for the hydrolysis of cellulose and hemicelluloses into fermentable sugars. Therefore, the pretreatment of lignocellulose is necessary before the hydrolysis process. This paper reviewed and prospected four methods and its reaction mechanism of lignocellulose pretreatment.

Nowadays, energy crisis and environmental issues attract a wide attention. On one hand, the concentration of carbon dioxide increases in atmosphere year by year which has already threaten the ecosystem on earth. On the other hand, converting carbon dioxide to fuel molecules with catalysts release not only environmental issues but also the energy crisis. The conversation and utilization of carbon dioxide by electrochemistry is a promising solution for energy crisis and environmental issues. However, the selectivity, current efficiency and stability of electrocatalysts are the key issues faced by the commercialization of carbon dioxide conversation. Based on the review of the research progress on heterogeneous electrochemical reduction of carbon dioxide, the relationships among the reduction products, faraday efficiency of reduction products and electrocatalysts, as well as the possible solutions to the problems faced currently by the electrocatalytic reduction of carbon dioxide were discussed. For the purpose of commercialization of carbon dioxide conversation and utilization, eletctrocatalysts with low-price, good stability, high efficiency and selectivity towards products should be developed. More importantly, researches should find a way to convert carbon dioxide to alcohol or hydrocarbon fuels efficiently.

Efficient transformation of cellulose into liquid fuels and chemicals is one key route for sustainable development of human society. With the chemical conversion, cellulose can be transformed to various small molecule organics, which are regarded as platform for production of liquid fuel or material. The progress in direct catalytic conversion of cellulose into valuable chemicals is reviewed in this paper, including preparation of 5-hydroxymethylfurfural (5-HMF), lactic acid, ethylene glycol, sorbitol and isosorbide. Finally, subsequent research topics on transformation of cellulose into valuable chemicals are prospected.

Rechargeable lithium-ion battery (LIB) has become the most promising battery system of mobile and fixed storage systems. However, unstable electrodeposition and uncontrollable interfacial reactions in conventional LIB occur in liquid electrolytes, leading to potential safety hazards. Nowadays, the all-solid-state lithium-ion battery can meet the requirement of energy storage in many aspects due to its high safety, high reliability, and high energy density. Nonetheless, solid-state electrolyte (SSE) still faces many challenges, such as low ionic conductivity at room temperature (1×10^-5-1×10^-3 S/cm) and poor stability of the interface between the electrode and the electrolyte. To speed up the research and development, the structure and conductivity of the inorganic perovskite (LLTO), garnet (LLZO), and sodium super ionic conductor (NASICON) were reviewed in this paper. In addition, the importance of the interface between electrolyte and electrode were emphasized and their effects on the performance of the battery were illuminated.

The technology of biomass pyrolysis to produce bio-oil was introduced, and the recent progresses in raw materials pretreatment, pyrolytic process and bio-oil upgrading were reviewed in this paper. In the raw materials pretreatment, three methods including microwave drying, torrefaction and acid-washing were introduced. In the pyrolytic process, the review focused on two novel pyrolytic processes, namely catalytic pyrolysis and co-liquefaction. On the aspect of bio-oil separation and refining, various new technologies such as catalytic hydroprocessing, catalytic cracking, catalytic esterification, emulsification, separation and purification were discussed and the development trend of industrialization was also analyzed.

It is an inexorable trend that offshore wind farm be constructed in deep sea in future. The existing installing technology and foundation can’t meet the new need of deep sea environment. Some new technologies will be the mainstream, including floating foundation, integral installation, self-propelled and self-elevating ship and so on. The sea near to middle-latitude zone in the northern hemisphere has unique advantages and active demand to develop wind power generation in deep sea. We need to draw up a plan to develop wind farm projects and technologies as early as possible.

Offshore Wind Farm (OWF) becomes hot topic in recent years. At the very beginning, developments of OWF in China are reviewed. The characteristics of Chinese OWFs are then discussed based on location, water depth, geological conditions and types of foundation. Later, the investment of OWF and subsidy from government are forecasted by analogies and comparisons. At last, many new progresses are presented.

Polyhydroxyalkanoate (PHA) is a type of polymer synthesized in many microbial cells under the imbalance of carbon and nitrogen, which has excellent biodegradability, biocompatibility and many material properties. It is a kind of new biological plastic that can replace the traditional plastic. At present, the biosynthesis of PHA mainly comes from the microbial fermentation. Other ways such as the transgenic plants and activated sludge are under development. This review summarizes the research progress of PHA biosynthesis pathways and approaches.

Metal bipolar plates have advantages such as high strength, good conductivity and heat transfer, low energy loss and good sealing performance. Additionally, metal bipolar plates are easy to process with low processing costs, which can be manufactured with ultra-thin thickness with high volume-specific power characteristic. Metal materials have gradually become the first choice for bipolar plate materials. The design and manufacturing process of the flow channel structure are the key factors affecting the forming quality and working performance of metal bipolar plates. The traditional and new channel structures used in metal bipolar plates were compared, and the impact of structural changes on fuel cell performance was analyzed. Plastic forming technologies and equipment were summarized, such as stamping, hydroforming, rubber pad forming, roll forming, electromagnetic forming and special forming. Finally, the flow channel structure design and manufacturing process of metal bipolar plate are prospected.

Graphite anode materials have been widely used in the field of lithium batteries because of their high specific capacity, low price and environmental friendliness. However, the material also exhibits some defects during the charge-discharge process, such as microcracks, graphitization degree reduction, contact loss, solid electrolyte interphase film change, lithium metal precipitation, inhomogeneity and other defects, which cause the capacity degradation of lithium-ion battery. In this paper, the mechanism of capacity decay in the cycle of anode materials was summarized, and the solutions of various degradation mechanisms were given briefly.

Power battery is an important component and a key technical point of electric vehicle, while the power battery standard in China still falls far behind the developed countries. Therefore, the power battery standard has become an important factor of restricting the electric vehicle development in China. This paper gives a comprehensive analysis to the current power battery standards in China based on the performances of batteries as the classification, and proposes a new power battery standard system framework.

 Fischer-Tropsch Synthesis (FTS) is an important route to produce various high quality hydrocarbon fuels or chemicals for different applications from synthesis gas (CO + H₂), which can be derived from nonpetroleum feedstocks such as natural gas, coal, or biomass. FTS processes from biomass derived syngas using the traditionally Fe, Co catalysts have received a great deal of interest in recent years. In this perspective, the latest developments in the preparation of high performance FTS catalysts are presented, including an overview of mesoporous materials and core–shell materials for FTS. The application of high performance FTS catalysts are highlighted for hydrocarbon production from biomass, including a comparative overview of the Fe- and Co-based catalysts performance. The productivity of cobalt-based catalysts at high conversion level is currently higher than that of iron-based catalysts. Nevertheless, it is argued that iron-based catalysts may be an attractive option for the Biomass-To-Liquid (BTL)-process. Development of more efficient, cheaper and tailored Fe-based catalysts is promising.

The Chinese medicine industry has expanded rapidly in recent years, producing a significant amount of Chinese medicine residue. The leftover cellulose from Chinese medicine is a valuable recyclable organic solid waste resource. Developing new technologies and enhancing of current disposal procedures for transforming Chinese medicine residue into high-value green energy products could bring considerable economic benefits to traditional Chinese medicine-related enterprises. Here, the benefits, drawbacks, and research progress for the mainstream technologies for disposing of Chinese medicine residue, including thermochemical and biochemical conversion technology, were thoroughly examined. A more systematic technique for disposing of Chinese medicine residue was also provided, and its engineering cases and outcomes were introduced in detail. In order to achieve effective and clean utilization of Chinese medicine residue, provide a new model for the green development of the Chinese medicine residues industry chain, and promote the development of China medicine and related fields environmental protection industry to play a role of demonstration and guidance, we present the prospect of energy disposal of Chinese medicine residue.

The electric vehicles (EVs) have great potential and advantage in energy conservation and emission reduction. However, the performance of EVs is restricted by power battery, whose safety and lifetime are affected by temperature. Thus, a suitable battery thermal management (BTM) system is indispensable to guarantee the whole performance of EVs. BTM system employed liquid medium has received much attention in recent years as its excellent cooling effect. In this paper, the fundamental of liquid medium based BTM was introduced and the development of research and application of liquid medium based BTM especially by using novel heat pipes were summarized. Some precautions during the design and application of liquid medium for cooling the battery were also pointed out.

Biomass activated carbon is a functionally porous carbon material produced by carbonizing and activating high-carbon biomass resources. It has a wide range of raw material sources, abundant surface functional groups and pore structures, excellent adsorption performance, and modification potential. In recent years, many scholars have used biomass as raw materials to prepare functional activated carbon, achieving significant results in the treatment of various organic wastewater scenarios. This article reviews the commonly used carbonization and activation methods in preparaing activated carbon, compares and analyzes modification methods such as surface acid-base modification, oxidation and reduction modification, metal loading modification, and microbial loading modification. It summarizes the applications of activated carbon in organic wastewater treatment scenarios such as adsorption purification, flocculation sedimentation, anaerobic digestion, biological filter beds, and constructed wetland filtration. Finally, it provides an outlook on the development prospects of activated carbon preparation technology.

Compressed air energy storage systems can effectively reduce the phenomenon of wind and solar energy being abandoned due to their randomness. However, their dynamic response time is long, and the unreasonable configuration of storage scale will affect its development. Therefore, this paper first proposes a hybrid energy storage system composed of liquid flow battery and compressed air energy storage to solve the problem of output fluctuation instability of grid-connected wind-solar complementary power generation systems. Secondly, based on typical hour load, wind turbine generating power, and photovoltaic generating power, a system maximum profit objective function is established for different scenarios, and the capacity configuration of the compressed air energy storage system is optimized using a cat swarm algorithm. Finally, the impact of the rated capacity and rated power of the compressed air energy storage system on the system's maximum profit is analyzed to verify the reliability of the algorithm. The results show that when the installed capacity of the wind turbine and photovoltaic system is 20 MW and 3.42 MW, respectively, and the capacity configuration of the compressed air energy storage system is 4 MW and 46.5 MW∙h, respectively, achieving its best economy, and 183 688.24 yuan can be saved every week in electricity purchase costs, with a maximum weekly profit of 30 543.86 yuan.

Wave simulation is a hot topic of Ocean Engineering. This article summarizes a method that can adapt to a wide range of random wave spectrums to emulate the waves environmentally. The method is converted to computer programs which are simple and convenient by language C and compute a large number of data used as data source to wave maker. The simulation result is verified by the experiment data. The test shows that the error between the analog spectrum and the target spectrum is lowest by using the numerical method presented in this paper. The acquisition of analog wave height data are used to estimate the spectrum by correlation function method. The numerical simulation method has a practical application value in the wave simulation.

Data centers represent the core infrastructure of the information industry. The energy consumption of data centers is a concern, as their power usage effectiveness (PUE) in China is much higher than that in the developed countries. So it is of great significance to conduct research on data center energy conservation. This paper focuses on the recent research advances in data center cooling systems from three perspectives: natural cooling, airflow organization optimization and cold storage. It is proposed that natural cooling technology should be adopted according to local conditions and that more in-depth research should be conducted in areas with poor natural cold source conditions. In addition, airflow organization optimization should enhance cabinet-level airflow organization for high-power density cabinets based on existing airflow control methods. Moreover, cold storage technology can bring data center operators huge economic benefits as well as substantial improvements to power generation and grid transmission distribution efficiency. Therefore, the existing cold storage technology cooling density needs to be improved, and further study should be conducted on the cold storage control strategies for optimal use in data centers.

 At present, storing CO₂ into the deep saline aquifers is one of the feasible ways to mitigate the greenhouse effect, when evaluate the reservoir’s theory sequestration, the amount of dissolved sequestration account for a large proportion of the total sequestration. This paper studies the kinetics and thermodynamics of CO₂ dissolution into saline aquifers by the data of previous experiments and simulation using Model Duan&Sun. The diffusion of CO₂ into underlying formation waters will increase the density of saline water, we can know whether convection is happening by judging with Rayleigh number, and which is conducive to the dissolution of CO₂. This paper also studies the effect of temperature, pressure and salinity on dissolution. The process of dissolution is slowly in the first few hundred years, at which leakage is easy to happen. Low temperature, high pressure and low brine salinity is more conducive to the dissolution of CO₂. Small droplets are more benefit for CO₂ sequestration.

A new method of calculation positive sequence voltage of asymmetric power grid and the application of the phase locked loop (PLL) based on dq transform is developed in this paper. Because of the negative sequence voltage component in power grid, the output of PLL is not accurate. According to the phase relationship between positive sequence and negative sequence, the trigonometric function method is proposed to extract positive sequence. This method is used in the three-phase voltage phase locked loop based on the dq synchronous reference frame transformation. The accuracy and stability of the PLL in the asymmetric power grid were improved by using this method. The importance of grid voltage feed forward for the control of the inverter was discussed. The advantages of the feed forward control by using positive sequence were analyzed. All the methods were improved in the experiments.

Corrosion and scaling often occur in the plant equipments, pipes and fittings that contact geothermal water or vapor in the geothermal energy utilization including power generation and direct exploration. Corrosion and scaling are usually the bottleneck problems which are very difficult to overcome. Hence, mechanism and control technique researches on the corrosion and scaling of geothermal fluids are of great practical significance. Recent research developments on the control or inhibition technologies of corrosion and scaling in geothermal fluid environments were summarized in this paper. Related contents include material selections of corrosion resistance and antifouling, coating layers, fluid pretreatments and chemical additives. Further research directions were suggested. The important areas are the studies on the predictions of corrosion and scaling trends of more geothermal fluids and geochemical chemistry simulation, scaling mechanisms in geothermal fluids, combination forces between coating layers and substrates, cathodic protection and corrosion and scaling hybrid inhibition techniques, etc.

The heat generation for lithium-ion batteries is composed of the reversible heat caused by the electrochemical reaction and the irreversible heat due to polarization during charge-discharge cycling. The materials of cobalt acid lithium battery begin to decompose once the internal temperature of the battery reached 82^oC. A series of uncontrolled chemical reactions are triggered, resulting in releasing a large amount of heat. With the aid of finite element technology, the reversible, irreversible heat and the decomposition heat are both considered in this work to simulate the internal temperature variation of lithium-ion batteries under different cooling conditions and ambient temperatures, which can provide theoretical basis to disclose the thermal runaway mechanism for this kind of battery.

Capacity fading is directly related to the cycle life of lithium-ion batteries. The reasons of capacity fading include growth of the solid electrolyte interface (SEI) film, degradation and dissolution and phase transition of active materials, overcharging-discharging, decomposition of the electrolyte, abnormal temperature, corrosion of current collector and so on. This article reviews the research progresses on capacity fading mechanisms of lithium-ion batteries in recent years.

Due to its good charge storage in electric double layer and rapid interlayer carrier transport, molybdenum disulfide (MoS2) with typically “sandwich-like” two-dimensional layered structure is a kind of ideal electrode materials for chemical power sources. In this paper, the structure and performance characteristics of MoS2 materials were briefly introduced. Research progresses of MoS2 materials used in chemical power sources were reviewed in recent five years. The main problems and challenges of MoS2 nanomaterials were analyzed. The solutions were emphatically discussed, especially the modulation of morphology and size. Finally, the development direction and application prospects of MoS2 nanomaterials in the future were summarized.

Perovskite solar cells is a kind of emerging all-solid-state planar solar cell and grew rapidly since its first appearance in 2009. It was reported that the photoelectric conversion efficiency of organic-inorganic hybrid perovskite solar cells has exceeded 24%, and the photoelectric conversion efficiency of all inorganic perovskite solar cells exceeded 17%. Compared with organic-inorganic hybrid perovskite solar cells, the thermostability of inorganic perovskite materials was higher, which makes it a hotspot in the research field of perovskite solar cells. In this paper, the latest research progress of all-inorganic perovskite solar cells was mainly reviewed, especially the improvement of the efficiency and stability of the all-inorganic perovskite solar cell types. The improvement of the perovskite film layer, results of optimizing the electronic transport layer and hole transport layer were described and reviewed in detail.

Lignin is the unique, renewable and natural aromatic polymer. The efficient transformation of lignin into phenolic monomers and other high value-added chemicals such as hydrocarbons has long been regarded as an important comprehensive utilization approach. In this paper, we focused on the basic structure and the main treatment technologies of this aromatic material. The recent progress in the catalytic thermal depolymerization and hydrogenolysis were reviewed intensively. The catalytic mechanism for the degradation of lignin characteristic chemical bond β-O-4 was also given. Furthermore, the current technique challenges were summarized. Moreover, future technologic explorations for the efficient application of lignin were proposed.

Multivalent metal-sulfur batteries have become a promising next-generation battery system due to their high specific capacity, low cost, and abundant resource reserves. Magnesium-sulfur (Mg-S) batteries, aluminum-sulfur (Al-S) batteries and zinc-sulfur (Zn-S) batteries are among the most promising candidates. However, the development of multivalent metal-sulfur batteries was hindered by many issues, such as the low electrical conductivity of sulfur, the large volume expansion during the transformation process, and the low utilization of sulfur. In addition, Mg-S and Al-S batteries lack suitable electrolytes, and Zn-S batteries suffer from poor electrochemical reversibility. Here, advances in multivalent metal-sulfur batteries on electrolyte exploitation, anode protection, cathode design, and separator optimization were systematically reviewed and future research prospects for multivalent metal-sulfur batteries were proposed.