Large-spectrum release of polyoxic manganese and batteries

In order to increase the pH potential, three possible methods are known: (1) changing the electrolysis conditions of the EMD, such as increasing the acid concentration in the electrolyte; (2) pickling the EMD after electrolysis; (3) preferably the parent in the electrolyte solution Raw materials are mainly used to reduce potassium content. Lowering the potassium content increases the pH potential.

The impurity potassium content in EMD refers to the potassium ions entering the crystal structure during the electrolysis, entering the pores of the EMD crystal or being adsorbed on the surface of the EMD, and not including the addition for electrolysis after electrolysis, or with the positive electrode mixture or the battery pack. Partially contacted potassium ions.

The results show that the potassium content in the EMD for high power discharge must be less than 2.510"4, preferably less than 1.510"4, or even 310"5; and the pH6 potential should be greater than 0.86V (2.510"4 and 1.510"4 There are different methods for measuring potassium content).

The EMD with these two conditions is discharged at 1A or 1.5A after being made into an LR6 battery, and its discharge capacity can be increased by 15% compared with the battery of the conventional EMD. The result is shown as 2. It can be seen that samples with high potassium content, low pH potential, high potassium and high pH potential, low potassium and low pH potential are not suitable for high power discharge.

Electron paramagnetic spectrum (EPR) parameter method EMD has two kinds of signals A and B in the electron paramagnetic spectrum (EPR), and there are two kinds of signal parameters - g factor and signal width DB0. Different EMDs have different DB0. The larger DB0, the larger the Mn3+/Mn4+ in EMD. The more OH groups, the more defect structures and the greater the disorder, which is suitable for embedding H+ in lye [7]. .

Method for Producing High Power Electrolytic Manganese Dioxide The hydrothermal method hydrothermal method is essentially an autoclave process, that is, electrolysis performed at a higher pressure when the cell temperature is higher than 100. High-power electrolytic manganese dioxide with a certain porosity can be produced by hydrothermal method and controlling certain electrolysis conditions. The optimum electrolysis conditions are shown in Table 1. The characteristics of the EMD obtained by the electrolysis of the conditions in Table 1 are shown in Table 2.

It can be seen from Table 2 that the characteristics of the sample fully comply with the characteristics of the HPEMD proposed in Section 1.2. The BET surface area is greater than 20 m 2 /g, the micropore area is greater than 8 m 2 /g, the porosity is greater than 0.035%, and the average radius of the large mesopores is greater than 3.2 nm. The LR6 battery made with such a sample was placed at 0.5A and 1.5A, and the capacity was up to 500$680mAh at a cutoff voltage of 1.1V. The discharge capacity was 1500mAh and 1200mAh at a cutoff voltage of 0.9V.

If the electrolyte solution is hydrothermally electrolyzed by using Mn2O3 as a raw material [8], Mn2O3 forms Mn2+ in the acid solution to obtain MnO2 by dissolving and dissolving the precipitate. Samples of different crystal forms will be obtained at different temperatures and different H2SO4 concentrations.

To obtain g-crystalline MnO2, the following trends are obtained: (1) increasing the temperature, decreasing the concentration of H2SO4, and increasing the Dewolff defect structure; (2) lowering the temperature and lowering the concentration of H2SO4, thereby increasing the Mn3+ fraction in g-MnO2. (y); (3) Lowering the temperature and increasing the H2SO4 concentration can increase the vacancy fraction (x) in g-MnO2.

It can be seen that the stable phase region of high-quality g-MnO2 is prepared under the conditions of low temperature and low H2SO4 concentration, corresponding to the smallest vacancy fraction (x), moderate Dewolff structural defects (Pr) and twins (Tw). )value. This hydrothermal method is safer because it can be carried out at lower temperatures and acid concentrations, and the equipment is less prone to corrosion.

Conditions for preparing high-power EMD with suitable particle size [4] To prepare an EMD having a suitable particle size suitable for high-power discharge, the key is to control the electrolysis conditions. The Ti plate was used as the anode and the graphite plate was used as the cathode. The electrolysis conditions are shown in Table 3. It can be seen from the table that the properties of sample 1$6 are consistent with the two conditions of high-power EMD: the alkaline potential is above 270mV, and the density is above 3.1g/cm3. The density is large because the maximum particle size is below 100mm. The particle content of 1mm or less is less than 15%, and the average diameter is between 20$60mm. It is suitable for high-power discharge batteries because it has high discharge potential and high filling rate. The sample 7$8 does not meet these conditions.

Changing the normal electrolysis parameters Anderson et al. [9, 10] proposed a method of changing the normal electrolysis parameters to make the EMD suitable for high power discharge. The main measures are: use high-purity electrolyte solution; choose the best electrolysis conditions: (1) temperature: 95$98; (2) current density J / (Acm "2): 26.9% J% 37.7; (3) c (H2SO4)c(MnSO4) is greater than 2 to obtain the best EMD crystal structure (g-e type), pore structure (balance pore volume), suitable surface area, and highest open circuit voltage (OCV). The anode current density is 20$100A/m2, the bath temperature is 90$99, c(MnSO4) is about 1mol/L, and c(H2SO4) is about 0.3mol/L. It can be seen that the main difference is in c(H2SO4) and c. (MnSO4) ratio. Table 4 shows the electrolysis parameters of the method and some characteristics of the sample. It can be seen from the table that the sample No. 1-4 adopts the changed electrolysis conditions: the concentration of H2SO4 is 25$40 g/L, The concentration of MnSO4 is between 5$20g/L and J is 26.9$37.7A/m2. The sample thus obtained has a surface area of ​​21$29m2/g, a compression density of 3.09$3.21g/cm3, and an IOCV of 1.62V or more. The intrinsic specific capacity is above 250 mAh/g, and the ratio Q of the XRD spectrum 220 to the peak height of 370 is between 0.47 and 0.76. Other electrolytic conditions such as samples 7 and 8 are Within the range of choice, the performance is therefore worse than that of the control sample 6 (the original sample has 61). It can be seen from the study that whether it is hydrothermal method or improved method, the EMD prepared should be suitable. For large current discharges, the performance parameters of interest are essentially the same.

The intrinsic discharge specific capacity of the LR6 battery obtained from the improved EMD sample obtained at 1W discharge rate can reach 68.2 mAh/g or more, while the original process is only 63.4 mAh/g; the energy of 1 W discharge can reach 755 mWh. The original process sample is only 637mWh.

Other methods for improving the high current discharge performance of alkaline zinc-manganese batteries The use of TiO2 additives for positive electrode additives is well known. In order to increase the discharge capacity of alkaline zinc-manganese batteries, TiO2 is generally added to the positive electrode. However, TiO2 is an n-type semiconductor with high resistivity, which is not conducive to large current discharge. Therefore, it is necessary to add an additional additive or to reduce the metal oxide with hydrogen. The modified additive may enter the pores of the TiO2 crystal structure or partially replace the lattice point of the original metal hydride to form the composite Ti1xMx-O2y to reduce the resistivity of TiO2, improve its ion exchange properties, and reduce corrosion. Or the occurrence of hydrogen evolution reaction. For example, using the modified additive Nb2O5, the following composite reaction occurs at high temperature [11]: (2) Thus, the resistivity of the additive is greatly reduced, as shown by 3.

In Ti1xO2y, the mole percentage x of the dopant M should be: 0.01% by mole "x" between 0.5% by mole, and the metal element M should have an octagonal coordination structure. In a different amount of x, the amount of EMD to C is 151 or (201), the amount of n-TiO2 is 1.6% by mole of EMD, and the modified dopant Nb2O5 is TiO2. The relative discharge time when the overflow half electrode is discharged is 0.1% by mole of the cation (i.e., 10% Nb2O5 in TiO2).

Other metal oxides which can be doped as modified TiO2 include NbO2, Ta2O5, WO3, GeO2, ZrO2, ThO2, In2O3, LiNiO2 and the like. Different doping modifiers have different mixing ratios, and the reaction temperature and time should also be different.

Conclusion In order to meet the requirements of digital high-current discharge of electronic devices, alkaline zinc-manganese batteries are still being explored and researched in various aspects, and continuous progress has been made. The center of gravity is still improving the performance of EMD. Developers are biased on one aspect. For example, the power factor is defined to find the discharge performance of EMD high voltage section. The definition of pH potential and alkaline potential is similar to the power coefficient. Porosity The optimization with the particle size distribution is to make the reaction area moderate and to facilitate the electrolyte in and out, to reduce the possible concentration polarization and reduce the reaction blind spot; and the potassium content is reduced as much as possible to avoid a-type MnO2. Form g, e-type. If these factors are taken into consideration together, it is possible to make further progress by utilizing the presently emerging composite material method for the combined electrolysis method in electrochemistry, preferably the electrolysis conditions for EMD suitable for large current discharge.

Golf Ball Printer

Golf ball Printer can print on any materials like Textile,Plastic,Leather,Glass,Metal,Acrylic,etc.,also our UV Printer can print any materials except textile without coating,more details,please contact with us.

More detial:

1. This machine wide application of personalized print: Suitable for printing on gifts, badges, signs, glasses, hair grip,
cards, leather, PVC board, crystal, wood, metal, U disk, mobile phone cases, IPAD cases and other materials.

2. Compared with those modified from R1290/1390 or R1900, our uncoated flatbed printer modified from
Epson R2000 with brand new motherboard and controller board, high resolution and stable performance.

3. Automatic height adjustment, moulding aeronautical aluminum alloy structure ensures good accuracy
and alignment.

Golf Ball Printer,6 Colors Golf Ball Printer,A3 Golf Ball Printer,Golf Ball Digital Printer,Golf Ball UV Flatbed Printer

Shenzhen Refinecolor Technology Co., LTD. , https://www.szfoodprinter.com