变电站蓄电池自动浮充系统的设计

介绍了变电站直流操作电源浮充系统的设计依据、电路设计方法及电路的工作原理,对科研和生产有较大的参考价值和经济效益。

Influence of oxidation heat on hard anodic film of aluminum alloy

The special experimental device and sulfuric acid electrolyte were adopted to study the influence of anodic oxidation heat on hard anodic film for 2024 aluminum alloy. Compared with the oxidation heat transferred to the electrolyte through anodic film, the heat transferred to the coolant through aluminum substrate is more beneficial to the growth of anodic film. The film forming speed, film thickness, density and hardness are significantly increased as the degree of undercooling of the coolant increases. The degree of undercooling of the coolant, which is necessary for the growth of anodic film, is related to the degree of undercooling of the electrolyte, thickness of aluminum substrate, thickness of anodic film, natural parameters of bubble covering and current density. The microstructure and performance of the oxidation film could be controlled by the temperature of the coolant.

Research progress of magnesium anodes and their applications in chemical power sources

Magnesium is a promising metal used as anodes for chemical power sources. This metal could theoretically provide negative discharge potential and exhibit large capacity during the discharge process. However, when the magnesium anode is adopted for practical applications, several issues, such as the discharge products adhered to the electrode surface, the self-discharge occurring on the anode material, and the detachment of metallic particles, adversely affect its inherently good discharge performance. In this work, the types of chemical power sources using magnesium as anodes were elaborated, and the approaches to enhance its anode performance were analyzed.

The Electrodeposition of Rhenium in Alkaline and Acidic Elektrolytes

The investigation of electrodeposition of rhenium in alkaline and acidic electrolytes was carried out, polarization curves were obtained by electrochemically and cyclically potentiodynamic methods. By the investigation of rhenium concentration, sulphuric acid, alkali, ammonium sulphate, temperature and acidity of solution, it was found that reaming velocity was an optimal regime and electrolyte composition for an obtaining of high quality rhenium deposits from an alkaline electrolyte and acidic electrolyte. It was defined that the process of electrodeposition of rhenium in alkaline electrolyte is accompanied by chemical polarization and the electrodeposition of rhenium in acidic electrolyte goes gradually with the formation of intermediate films of sediments,

Kinetics of CO_2 reduction in KOH/methanol electrolyte on Pb electrode

The electrochemical reduction of CO2 on a Pb electrode was investigated in 0. 1 mol/L KOH/methanol electrolyte at different temperatures and pressures. A graphite electrode was employed as the counter electrode, and an AglAgCl （sat. KCl） electrode was used as the reference electrode. The Tafel plots of the products by the electrochemical reduction of CO2 showed that the formation process of HCOOH differed from that of CO and the reduction of CO2was not limited by the diffusion of CO2 in the investigated potential range. Kinetic analysis indicated that the reaction orders were 0. 573 for electrochemical reduction of CO2 to CO and 0. 671 for CO2 to HCOOH in the cathodic direction.

Waterproof lithium metal anode enabled by cross-linking encapsulation

Lithium (Li) metal is considered as the ultimate anode choice for developing next-generation high-energy batteries. However, the poor tolerance against moist air and the unstable solid electrolyte interphases (SEI) induced by the intrinsic high reactivity of lithium bring series of obstacles such as the rigorous operating condition, the poor electrochemical performance, and safety anxiety of the cell, which to a large extent hinder the commercial utilization of Li metal anode. Here, an effective encapsulation strategy was reported via a facile drop-casting and a following heat-assisted cross-linking process. Benefiting from the inherent hydrophobicity and the compact micro-structure of the cross-linked poly(vinylidene-co-hex afluoropropylene) (PVDF–HFP), the as-encapsulated Li metal exhibited prominent stability toward moisture, as well corroborated by the evaluations both under the humid air at 25 °C with 30% relative humidity (RH) and pure water. Moreover, the encapsulated Li metal anode exhibits a decent electrochemical performance without substantially increasing the cell polarization due to the uniform and unblocked ion channels, which originally comes from the superior affinity of the PVDF–HFP polymer toward nonaqueous electrolyte. This work demonstrates a novel and valid encapsulation strategy for humiditysensitive alkali metal electrodes, aiming to pave the way for the large-scale and low-cost deployment of the alkali metal-based high-energy-density batteries.

Solvating power regulation enabled low concentration electrolyte for lithium batteries

Li^(+) solvation structures have a decisive influence on the electrode/electrolyte interfacial properties and battery performances.Reduced salt concentration may result in an organic rich solid electrolyte interface(SEI)and catastrophic cycle stability,which makes low concentration electrolytes(LCEs)rather challenging.Solvents with low solvating power bring in new chances to LCEs due to the weak salt-solvent interactions.Herein,an LCE with only 0.25 mol L^(-1) salt is prepared with fluoroethylene carbonate(FEC)and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether(D_(2)).Molecular dynamics simulations and experiments prove that the low solvating power solvent FEC not only renders reduced desolvation energy to Li^(+) and improves the battery kinetics,but also promotes the formation of a LiF-rich SEI that hinders the electrolyte consumption.Li||Cu cell using the LCE shows a high coulombic efficiency of 99.20%,and LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)||Li cell also exhibits satisfying capacity retention of 89.93%in 200 cycles,which demonstrates the great potential of solvating power regulation in LCEs development.

Effect of electrochemical oxidation on carbon nanotube electrodes of electric double layer capacitors

Electrochemical oxidation of the carbon nanotube (CNT) polarizable electrodes of electric double layer capacitors (EDLCs) was studied. It indicated that electrochemical oxidation elevated the available surface area of the electrodes and introduced some kinds of functional group on the CNT surfaces. The specific capacitances of the polarizable electrodes with organic electrolyte could be enhanced from 22.4 F g-1 to 78.2 F g-1 after electrolysis oxidization. The enhancement of the specific capacitance depends on the extent of electrochemical oxidation. Using acidic electrolyte for electrochemical oxidation has different effects on modifying the performances of the CNT polarizable electrodes compared to using basic electrolyte.

“Water in salt/ionic liquid”electrolyte for 2.8 V aqueous lithium-ion capacitor

Development of high-voltage electrolytes with non-flammability is significantly important for future energy storage devices.Aqueous electrolytes are inherently non-flammable,easy to handle,and their electrochemical stability windows(ESWs)can be considerably expanded by increasing electrolyte concentrations.However,further breakthroughs of their ESWs encounter bottlenecks because of the limited salt solubility,leading to that most of the high-energy anode materials can hardly function reversibly in aqueous electrolytes.Here,by introducing a non-flammable ionic liquid as co-solvent in a lithium salt/water system,we develop a"water in salt/ionic liquid"(WiSIL)electrolyte with extremely low water content.In such WiSIL electrolyte,commercial niobium pentoxide(Nb2O5)material can operate at a low potential(-1.6 V versus Ag/AgCl)and contribute its full capacity.Consequently,the resultant Nb2O5-based aqueous lithium-ion capacitor is able to operate at a high voltage of 2.8 V along with long cycling stability over 3000 cycles,and displays comparable energy and power performance(51.9 Wh kg^-1 at 0.37 kW kg^-1 and 16.4 Wh kg^-1 at 4.9 kW kg^-1)to those using non-aqueous electrolytes but with improved safety performance and manufacturing efficiency.