Preparation methods of nano-coated positive electrode materials and secondary aluminium cell using nano-coated positive electrode materials

Abstract

The invention discloses a novel high-energy secondary aluminium cell and a preparation method. The aim is to provide a method for preparing nano material-coated positive electrode active materials, by coating the positive and negative electrode active materials with the nano materials, it is possible to subject the positive and negative electrode active materials to nano treatment; therefore, thehigh-energy secondary aluminium cell features obviously improved properties, simple material composition, low cost, simple technology, environmentally friendly synthesis path, relatively high capacity and relatively good cycle property and market prospect. The secondary aluminium cell comprises the positive and negative electrodes prepared by the modified positive and negative electrode active materials coated by the nano material surfaces, or any one electrode in the singly coated positive or negative electrode active materials, polyelectrolyte (ionic liquid) and a diaphragm. The coating materials are semimetals, oxides, salts or conductive polymers. The invention uses the nano materials in the secondary aluminium cell for the first time; therefore, the cell has higher open circuit voltage and reversible capacity and better cycle property.

Description

technical field [0001] The invention relates to a preparation method of a positive electrode active material, a secondary aluminum battery and a preparation method thereof, and more particularly to a preparation method of a nano-coated positive electrode active material. A secondary aluminum battery and a preparation method thereof, or a secondary aluminum battery with a nanometer single-coated positive electrode or a negative electrode active material, and a preparation method thereof. Background technique [0002] With the thirst for high energy density power sources, the development and application of inexpensive, safe, environmentally friendly and high-performance secondary batteries is urgently needed. A secondary aluminum-sulfur battery with aluminum and its alloys as the negative electrode material and sulfur-based material as the positive electrode is one of the batteries that meets the above requirements. Aluminum and sulfur materials are safe, environmentally frie...

AI Technical Summary

Problems solved by technology

However, primary aluminum batteries represented by aluminum-air batteries cannot be recharged and cannot be recycled because the electrolyte system is an aqueous solution.

[0004] There are many forms of sulfur. Elemental sulfur is an insulator of ions and electrons at room temperature. The small molecular organic sulfides produced when the sulfur-sulfur bond is broken are dissolved in the electrolyte to form disordered sulfur with irreversible reactions, resulting in rapid self-discharge and capacity. Attenuation and other issues, so that the cycle performance of the battery will soon decline

[0005] In order to avoid the above problems and endow the battery with excellent performance, Naoi first synthesized the dithiodianiline polymer positive electrode material (J. Electrochem. Soc., 1997, 144 (6): L173) in 1997 and applied it in the lithium battery system It has been well applied in , but because the preparation raw materials of this type of material are expensive and the synthesis process is complicated, it is difficult to obtain practical application; US Pat 5441831, US Pat 5460905, US Pat 5601947 and US Pat 5609720 disclose carbon-sulfur compound, but it has the problem of low theoretical capacity, and it is not easy to regenerate materials with the same molecular structure; Skothcim applied polycarbon disulfide (PCS) electrodes to secondary lithium batteries and obtained better capacity and cycle performance (US Pat 5460905 ), but the pollution to the environment during the synthesis process cannot be ignored; Wang Jiulin used the method of high-temperature dehydrogenation to achieve branched cross-linking of S-S structure on polyethylene oxide, polyvinylidene fluoride and other polymer substrates (CN1339839A) , due to the continuous generation of corrosive gases during the synthesis process, it has a great impact on the environment and equipment, so there are certain defects in this synthesis route

[0006] Aluminum as a negative electrode material also has some problems that cannot be ignored: (1) the actual working potential of aluminum is much higher than the theoretical value; there is a strong affinity between aluminum alloy and oxygen, in air and aqueous solution, the surface generates a The dense passivation oxide film makes the electrode potential of aluminum not reach the proper theoretical electrode potential, and also causes voltage hysteresis during discharge.

(2) Aluminum is a typical amphoteric metal with high activity and is easy to react with acid and alkali to destroy the oxide film. Once the oxide film is destroyed, it will be corroded quickly