Natural gas hydrate (NGH) has attracted much attention as a new alternative energy globally. However, evaluations of global NGH resources in the past few decades have casted a decreasing trend, where the estimate as of today is less than one ten-thousandth of the estimate forty years ago. The NGH researches in China started relatively late, but achievements have been made in the South China Sea (SCS) in the past two decades. Thirty-five studies had been carried out to evaluate NGH resource, and results showed a flat trend, ranging from 60 to 90 billion tons of oil equivalent, which was 2–3 times of the evaluation results of technical recoverable oil and gas resources in the SCS. The big difference is that the previous 35 group of NGH resource evaluations for the SCS only refers to the prospective gas resource with low grade level and high uncertainty, which cannot be used to guide exploration or researches on development strategies. Based on the analogy with the genetic mechanism of conventional oil and gas resources, this study adopts the newly proposed genetic method and geological analogy method to evaluate the NGH resource. Results show that the conventional oil and gas resources are 346.29 × 108 t, the volume of NGH and free dynamic field are 25.19 × 104 km3 and (2.05–2.48) × 106 km3, and the total amount of in-situ NGH resources in the SCS is about (4.47–6.02) × 1012 m3. It is considered that the resource of hydrate should not exceed that of conventional oil and gas, so it is 30 times lower than the previous estimate. This study provides a more reliable geological basis for further NGH exploration and development.
Layer-structured cathode materials for lithium-ion batteries are considered. These materials, such as LCO, NCM, NCA, lithium rich cathode oxides and blended cathodes are well-known for the intercalation mechanism. Future of lithium-ion batteries is also strongly based on these cathode chemistries, but to overcome some drawbacks and challenges, the improved materials are needed. In this chapter, modification of layer-structured cathode materials by doping and coating are discussed. Especially, coating materials and doping methods are considered.
Lithium-ion capacitors (LICs) represent an innovative hybridization in the energy storage field, effectively combining the best features of supercapacitors and lithium-ion batteries. However, the theoretical advantage of LICs is impeded by the low reaction efficiency of the negative electrode material and significant volume expansion. Two-dimensional (2D) materials, due to their unique morphology, abundant pores, rich active centers, and adjustable composition, have been widely studied and developed as negative electrodes for LICs. Therefore, it is imperative to provide a timely review of the latest advancements in the field. The review initiates with a detailed exploration of the infrastructure, key performance evaluation parameters, and the underlying energy storage mechanisms that define LICs. Subsequently, the focus shifts towards the cutting-edge research surrounding 2D materials, including graphene, MXene, transition-metal dichalcogenides, and transition-metal oxides. The review further elaborates on the typical applications of these 2D materials within LIC frameworks, highlighting their unique properties and contributions to enhanced energy storage solutions. In conclusion, the discussion addresses the significant challenges these materials encounter within LIC applications, such as scalability, cost, and integration issues, while also projecting future development prospects. It outlines both the current limitations and the potential breakthroughs that could pave the way for more advanced and efficient LIC technologies.
This article presents the electrochemical results that can be achieved for pure LiNiO2 cathode material prepared with a simple, low-cost, and efficient process. The results clarify the roles of the process parameters, precipitation temperature, and lithiation temperature in the performance of high-quality LiNiO2 cathode material. Ni(OH)2 with a spherical morphology was precipitated at different temperatures and mixed with LiOH to synthesize the LiNiO2 cathode material. The LiNiO2 calcination temperature was optimized to achieve a high initial discharge capacity of 231.7 mAh/g (0.1 C/2.6 V) with a first cycle efficiency of 91.3% and retaining a capacity of 135 mAh/g after 400 cycles. These are among the best results reported so far for pure LiNiO2 cathode material.
The European Union's circular economy strategy aims to increase the recycling and re-use of products and waste materials. According to the strategy, the use of industry waste materials and side flows is required to be more effective. In this research, a chemical precipitation method to simultaneously remove ammonium and phosphate from the reject water of anaerobic digestion plant using calcined paper mill sludge and fly ash as a precipitant, was tested. Paper mill sludge is a waste material formed in the paper-making process, and fly ash is another waste material formed in the power plant. Objective of this research was to test whether these industrial waste streams could be used as low cost precipitation chemicals for ammonium and phosphate removal from wastewaters and whether the precipitate could be suitable for fertilizer use. Results indicated that calcined paper mill sludge had high removal efficiency for both ammonium (97%) and phosphate (73%). Fly ash also had good removal efficiency for both ammonium nitrogen (74%) and phosphate (59%) at 20 ± 2 °C. The precipitates contained high concentrations of nitrogen and phosphate and could be used as a recycled fertilizer. Other possible mechanisms for the removal of phosphate and ammonium were considered.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)