Modeling of Large-Scale Hydrogen Storage System Considering Capacity Attenuation and Analysis of Its Efficiency Characteristics

In the existing power system with a large-scale hydrogen storage system,there are problems such as low efficiency of electric-hydrogen-electricity conversion and single modeling of the hydrogen storage system.In order to improve the hydrogen utilization rate of hydrogen storage system in the process of participating in the power grid operation,and speed up the process of electric-hydrogen-electricity conversion.This article provides a detailed introduction to the mathematical and electrical models of various components of the hydrogen storage unit,and also establishes a charging and discharging efficiency model that considers the temperature and internal gas partial pressure of the hydrogen storage unit.These models are of great significance for studying and optimizing gas storage technology.Through these models,the performance of gas storage units can be better understood and improved.These studies are very helpful for improving energy storage efficiency and sustainable development.The factors affecting the charge-discharge efficiency of hydrogen storage units are analyzed.By integrating the models of each unit and considering the capacity degradation of the hydrogen storage system,we can construct an efficiency model for a large hydrogen storage system and power conversion system.In addition,the simulation models of the hydrogen production system and hydrogen consumption system were established in MATLAB/Simulink.The accuracy and effectiveness of the simulation model were proved by comparing the output voltage variation curve of the simulation with the polarization curve of the typical hydrogen production system and hydrogen consumption system.The results show that the charge-discharge efficiency of the hydrogen storage unit increases with the increase of operating temperature,and H2 and O2 partial voltage have little influence on the charge-discharge efficiency.In the process of power conversion system converter rectification operation,its efficiency decreases with the increase of temperature,while in the process of inverter operation,power conversion system efficiency increases with the increase of temperature.Combined with the efficiency of each hydrogen storage unit and power conversion system converter,the upper limit of the capacity loss of different hydrogen storage units was set.The optimal charge-discharge efficiency of the hydrogen storage system was obtained by using the Cplex solver at 36.46%and 66.34%.

Practical evaluation of prelithiation strategies for next-generation lithium-ion batteries

With the increasing market demand for high-performance lithium-ion batteries with high-capacity electrode materials,reducing the irreversible capacity loss in the initial cycle and compensating for the active lithium loss during the cycling process are critical challenges.In recent years,various prelithiation strategies have been developed to overcome these issues.Since these approaches are carried out under a wide range of conditions,it is essential to evaluate their suitability for large-scale commercial applications.In this review,these strategies are categorized based on different battery assembling stages that they are implemented in,including active material synthesis,the slurry mixing process,electrode pretreatment,and battery fabrication.Furthermore,their advantages and disadvantages in commercial production are discussed from the perspective of thermodynamics and kinetics.This review aims to provide guidance for the future development of prelithiation strategies toward commercialization,which will potentially promote the practical application of next-generation high-energy-density lithium-ion batteries.

CC-CV charge protocol based on spherical diffusion model

A new insight into the constant current-constant voltage （CC-CV） charge protocol based on the spherical diffusion model was presented. From the model, the CV-charge process compensates, to a large extent, the capacity loss in the CC process, and the capacity loss increases with increasing the charging rate and decreases with increasing the lithium-ion diffusion coefficient and using a smaller r value （smaller particle-size and larger diffusion coefficient） and a lower charge rate will be helpful to decreasing the capacity loss. The results show that the CC and the CV charging processes, in some way, are complementary and the capacity loss during the CC charging process due to the large electrochemical polarization can be effectively compensated from the CV charging process.

A high-durability aqueous Cu-S battery assisted by pre-copper electrochemistry

Although research interest in aqueous metal-sulfur batteries(AMSs)has surged due to their intrinsic low cost and high capacity,the practical application of AMSs remains a considerable challenge because of the restrictive cycling stability.To circumvent this issue,we propose an innovative and simple pre-copper strategy to realize a high-durability aqueous Cu-S battery.The precopper strategy can effectively promote a stable metal dissolution/deposition,compensate for charge carriers,and facilitate reaction kinetics during the subsequent process.As a result,the aqueous Cu-S battery when coupled with S-decorated porous Ti_(3)C_(2)(S-d-Ti_(3)C_(2))exhibits excellent electrochemical performance,delivering a highly reversible capacity of 1805.4 mAh·g^(-1)in the initial cycle at 0.8 A·g^(-1),impressive cycling stability with 90.2%capacity retention over 800 cycles,and ultralow polarization~0.08 V even at a high current density of 3.1 A·g^(-1).The findings obtained in this work could pave the way for the design of highperformance sulfur-based aqueous batteries,which fill the vacancy of the necessary metal anode,delivering merits in both cost and cycle life.