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The addition of electrolyte additives shows significant effect on the low temperature performance of lithium-ion batteries (LIBs), but the underlying mechanism remains to be further elucidated and understood. Here, we take methyl acetate (MA) as an example to explore the mechanism of low-temperature additives on the graphite interface. The effects of the MA additive, demonstrated by scanning electrochemical microscopy (SECM) and atomic force microscopy, optimize the electron insulating properties and mechanical properties of the graphite anode. This optimized electrolyte improves the graphite performance with a capacity of 343.8 mA h g−1 after 300 cycles at room temperature and 302.9 mA h g−1 at low temperature (−10 °C), while the capacity decreases sharply without MA, and at the same time improves the rate performance which increases the capacity retention at 4C from 18% to 55%. The reinforced electronic insulation SEI is observed in the first discharge process with MA addition in SECM feedback mode and remains stable in the next cycles. The results show that a stable ultrathin SEI with an inorganic/organic bilayer structure rapidly forms in the first cycle with MA addition, the outer organic layer provides mechanical suppression and the inner inorganic layer promotes the interface mechanical strength with excellent ion transport, which suppresses the continuous decomposition of electrolytes and improves the mechanical properties of the SEI. [ABSTRACT FROM AUTHOR]

The oxygen discharge process significantly affects the electrochemical performance of a proton exchange membrane water electrolyzer (PEMWE), which requires an optimal structure of the flow field implemented in the bipolar plate (BP) component. In this study, we numerically investigated the two-phase (liquid water and oxygen) flow in the PEMWE's channel region with different outlet manifold structures utilizing the volume of fluid (VOF) model. Then, the oxygen volume fraction at the liquid/gas diffusion layer (L/GDL) surface, i.e., the interface of the channel and L/GDL, obtained by the liquid water and oxygen flow model was incorporated into a three-dimensional (3D) PEMWE model, which made it possible to predict the influence of the outlet manifold structure on the multiple transfers inside the whole electrolyzer as well as the electrochemical performance. The results indicate that the existence of oxygen in the flow field significantly decreased the electrolyzer voltage at a fixed operation current density and deteriorated the uniform distribution of the oxygen amount, current density (corresponding to the electrochemical reaction rate) and temperature in the membrane electrode assembly (MEA), indicating that the rapid oxygen removal from the flow field is preferred in the operation of the electrolyzer. Moreover, slight increases in the width of the outlet manifold were helpful in relieving the oxygen accumulation in the anode CL and, hence, improved the electrolyzer performance with more uniform distribution characteristics. [ABSTRACT FROM AUTHOR]

In practical engineering applications, the investment, income, subsidies and other costs of energy storage batteries have a certain impact on the overall economic benefits of primary frequency modulation. The larger the capacity of the configured battery energy storage system, the better the primary frequency modulation effect will be, but at the same time, the problem is that the cost of investment in the energy storage system will increase, which will offset the benefits of primary frequency modulation loss reduction of its auxiliary photovoltaic station from an economic perspective. Therefore, this paper will clarify the benefits and costs of the primary frequency modulation application environment of the energy storage system, and establish an economic analysis model from delaying the investment of photovoltaic station equipment, reducing the cost of light waste, environmental benefits, direct benefits, government subsidies, energy storage investment costs and other aspects. Finally, a photovoltaic station is taken as an example to simulate and analyse the sensitivity.

Calcium‐ion batteries (CIBs) are considered as potential next‐generation energy storage systems due to their abundant reserves and relatively low cost. However, irreversible structural changes and weak conductivity still hinder in current CIBs cathode materials. Herein, an organic molecular intercalation strategy is proposed, in which V2O5 regulated with quinoline, pyridine, and water molecules are studied as cathode material to provide fast ion diffusion channels, large storage host, and high conductivity for Ca ions. Among them, V2O5‐quinoline (QVO) owns the largest interplanar spacing of 1.25 nm and the V‐O chains are connected with organic molecular by hydrogen bond, which stabilizes the crystal structure. As a result, QVO exhibits a specific capacity of 168 mAh g−1 at 1 A g−1 and capacity retention of 80% after 500 cycles at 5 A g−1 than the other materials. Furthermore, X‐Ray diffraction and X‐ray absorption spectroscopy results reveal a reversible order‐disorder transformation mechanism of Ca2+ for QVO, which can make full use of the abundant active sites for high capacity and simultaneously achieve fast reaction kinetics for excellent rate performance. These results demonstrate that QVO is a promising cathode material for CIBs, providing more choices for the development of high‐performance CIBs. [ABSTRACT FROM AUTHOR]