Application of nano-magnesium oxide in lithium battery separator
The lithium-ion battery is capable of being recharged twice during use and is a secondary rechargeable battery. The main principle of operation is the repeated movement of lithium ions between the positive and negative electrodes.
With the continuous development of lithium-ion batteries, the application field is gradually expanding, and the use of cathode materials has changed from a single to a diversified direction, including: olivine lithium ferrous phosphate, layered lithium cobaltate, spinel lithium manganate and so on, to achieve the coexistence of a variety of materials.
Nano magnesium oxide is a new type of nanoparticle material with white powder appearance, high purity, large specific surface area, composed of fine grains, with obvious small size effect, surface effect, quantum size effect and macroscopic tunneling effect, no gas inside the electrode, easier surface regeneration, small hydrogen and oxygen overpotential, cheap, etc., so it is more widely used.
Brief introduction to the addition of magnesium oxide nanoparticles to lithium batteries.
1. Lithium ion battery choose to add 10-100g/L diameter between 0.05-10μm TiO2, SiO2, Cr2O3, ZrO2, CeO2, Fe2O3, BaSO, SiC, MgO and other insoluble solid particles, will be made of materials as lithium ion with good charge and discharge efficiency, high specific capacity, stable cycle performance.
2. Lithium battery cathode material, the nano magnesium oxide as a conductive dopant, through the solid-phase reaction to generate magnesium-doped lithium iron manganese phosphate, and further made of nanostructured cathode material, its electrical conductivity up to 10-2S/cm, the actual discharge capacity of 240mAh/g. This new cathode material has high energy, environmental protection, low cost characteristics, suitable for liquid and colloidal lithium-ion batteries, small and medium-sized polymer It is particularly suitable for high-power power batteries.
3. Optimisation of the capacity and cycling performance of lithium spinel manganate batteries. In the electrolyte of lithium-ion batteries with lithium spinel manganate as the cathode material, magnesium oxide nanoparticles are added as a deacidifier to remove acid at a rate of 0.5-20% of the electrolyte weight. By de-acidifying the electrolyte, the content of free acid HF in the electrolyte is reduced to below 20 ppm, which reduces the dissolution effect of HF on LiMn2O4 and improves the capacity and cycling performance of LiMn2O4.
4. An alkaline solution of magnesium oxide nanoparticles as a pH adjuster and an aqueous ammonia solution as a complexing agent were mixed and added to an aqueous solution containing a mixture of cobalt and nickel salts to co-precipitate Ni-CO composite hydroxide. Lithium hydroxide is added to the Ni-CO complex hydroxide and the mixture is heat treated at 280-420°C. The resulting product is heat-treated at 650-750°C, and the average particle size of the lithium composite oxide decreases or the stacking density increases as a result, depending on the time of co-precipitation. When the lithium composite oxide is used as an anode active material, a high capacity lithium ion secondary battery is obtained, while the actual amount of magnesium oxide added depends on the specific formulation.
