Xin Jin

Zinc (Zn) metal is considered the promising anode for “post‐lithium” energy storage due to its high volumetric capacity, low redox potential, abundant reserve, and low cost. However, extravagant Zn is required in present Zn batteries, featuring low Zn utilization rate and device‐scale energy/power densities far below theoretical values. The limited reversibility of Zn metal is attributed to the spontaneous parasitic reactions of Zn with aqueous electrolytes, that is, corrosion with water, passive by‐product formation, and dendrite growth. Here, a new ion‐selective polymer glue coated on Zn anode is designed, isolating the Zn anode from the electrolyte by blocking water diffusion while allowing rapid Zn²⁺ ion migration and facilitating uniform electrodeposition. Hence, a record‐high Zn utilization of 90% is realized for 1000 h at high current densities, in sharp contrast to much poorer cyclability (usually < 200 h) at lower Zn utilization (50–85%) reported to date. When matched with the vanadium‐based cathode, the resulting Zn‐ion battery exhibited an ultrahigh device‐scale energy density of 228 Wh kg⁻¹, comparable to commercial lithium‐ion batteries.

Aiming at the motion stagnation and local damage failure of a 2D needled Cf/SiC adjustable nozzle during operation, the motion performance of the nozzle and the contact stress at the key parts were studied. A dynamic simulation method of the nozzle with adjustable nozzle considering clearance fit was established, and the throat contraction process was analyzed by a simulation example. Firstly, the critical analysis positions of the nozzle were determined by trial calculation, and the model was simplified and the mesh was optimized. Then, the simulation was carried out under the boundary conditions involving multiple fields. The motion characteristics of the nozzle throat during the throat contraction process were analyzed due to the velocity results, and the stress state and failure state at the key position of the nozzle during the impact process were finally determined.

This article describes a large-scale biogas plant in a dairy farm located in the Tongzhou District of Beijing. It is has a treatment capacity of 30t manure and 30t wastewater per day, a total of 60t/d with a residence time of 20 days. Input material undergoes mesophilic fermentation inside the digester, which also directly stores the biogas above the slurry within the same tank. This storage method has been found to be advantageous for large scale biogas plants in China. Along with biogas production, this particular plant also adopted a combined heat and power (CHP) system. CHP systems burn biogas for generating, but they also convert the excess heat into electricity. In this case study, the CHP system generates 160kw of electricity. These comprehensive systems can provide heat, clean electricity and organic fertilizer, which can result in economic, social and energy saving benefits. Due to these multiple benefits, CHP systems are commonly used when dealing with large scale livestock biogas projects.