Comparison and analysis of vanadium batteries and lithium batteries

1. The working principle of vanadium batteries and lithium batteries is different. All vanadium redox batteries use vanadium ion solutions with different valences as active materials for the positive and negative electrodes, and store them in their respective electrolyte storage tanks. When charging and discharging the battery, the electrolyte is used by the pump to circulate through the positive and negative compartments of the battery from the external storage tank, and oxidation and reduction reactions occur on the electrode surface to realize the charging and discharging of the battery. . Lithium battery is actually a kind of lithium ion concentration difference battery. The positive and negative electrodes are composed of two different lithium ion intercalation compounds. When charging, Li+ is extracted from the positive electrode and inserted into the negative electrode through the electrolyte. The negative electrode is in a lithium-rich state and the positive electrode is in a lithium-poor state. At the same time, the compensation charge of electrons is supplied from the external circuit to the carbon negative electrode to ensure the charge balance of the negative electrode. The opposite is true during discharge. Li+ is extracted from the negative electrode and inserted into the positive electrode through the electrolyte, and the positive electrode is in a lithium-rich state. Under normal charge and discharge conditions, lithium ions are inserted and extracted between layers of layered structured carbon materials and layered structured oxides, generally only causing changes in the interlayer spacing without destroying the crystal structure. During the charging and discharging process, the negative electrode material The chemical structure is basically unchanged. Therefore, from the perspective of the reversibility of the charge and discharge reaction, the lithium battery reaction is an ideal reversible reaction. 2. The energy of the vanadium battery is stored in the electrolyte, and the battery capacity can be added by adding the volume of the electrolyte storage tank or increasing the concentration of the electrolyte. That is, for vanadium batteries with the same power output, the capacity can be adjusted arbitrarily according to demand, which is very suitable for large-capacity energy storage applications; the capacity of lithium batteries is related to the positive and negative materials. 3. The output power of the vanadium battery is determined by the area involved in the reaction in the battery stack. It can be adjusted to meet different power requirements by adding or reducing single cells and different battery packs in series and parallel. At present, the power of vanadium batteries in commercial demonstration operation in the United States has been Up to 6000kW; it is difficult for lithium batteries to achieve such a large energy storage capacity; 4. The charge and discharge of vanadium batteries do not involve solid-phase reactions, and the theoretical life of the electrolyte is unlimited and can be used for a long time; lithium batteries involve solid-phase reactions, and electrolyte use Life is limited; 5. The vanadium battery has a fast response speed and can be started instantly. It only takes 0.02 seconds to switch the charge and discharge state during operation, and the response speed is 1 millisecond; 6. The theoretical charge-discharge time ratio of the vanadium battery is 1:1 (the actual operation is 1.5 -1.7: 1), support frequent high-current charge and discharge, deep charge and discharge have little effect on battery life, the positive and negative active materials of the battery in the charge and discharge state are all liquid phases, and there will be no battery factors such as nickel-hydrogen batteries and lithium batteries. The growth of dendrites on the electrode will puncture the diaphragm and cause the risk of battery short circuit; 7. The energy storage capacity of vanadium batteries can be accurately measured; lithium batteries cannot. 8. Vanadium batteries can increase the operating time of the system by adding electrolyte or replacing electrolyte. By replacing the electrolyte, instant recharging can be achieved, similar to refueling a car; lithium batteries cannot. 9. The vanadium battery system has a long service life, and the charge-discharge cycle life can exceed 10,000 times, which is much longer than that of lithium batteries. At present, the vanadium battery module with the longest running time for commercial demonstration of VRBPowerSystems in Canada has been in normal operation for more than 9 years, with a charge-discharge cycle life of more than 18,000 times; 10. The safety of vanadium batteries is high: vanadium batteries have no potential explosion or fire hazard, even if they are , There is no danger when the negative electrolyte is mixed, except that the temperature of the electrolyte rises slightly; lithium batteries have the potential to explode or catch fire. 11/ In addition to ion membrane, vanadium batteries have cheap materials and abundant sources. No precious metals are used as electrode catalysts, and the cost is low. Lithium batteries are more expensive, resources are scarce, and precious metals must be used. 12. The vanadium battery electrolyte can be used for a long time without polluting emissions and is environmentally friendly; the lithium battery electrolyte cannot be recycled and has certain pollution. Disclaimer: Some pictures and content of the articles published on this site are from the Internet, please contact to delete if there is any infringement. Previous: How to extend the life of the lithium battery of electric vehicles