Rechargeable aluminum-sulfur battery and preparation method thereof

Abstract

The invention discloses a rechargeable aluminum-sulfur battery and a preparation method thereof. The rechargeable aluminum-sulfur battery comprises a positive pole, a negative pole, an electrolyte anda diaphragm, wherein the positive pole is prepared from a cathode active material, a conductive agent, a binder, an organic solvent and a current collector for electric conduction; the cathode activematerial is a sulfur / carbon nanotube composite material, and the conductive agent, the binder, the organic solvent and the current collector for electric conduction are conventional cathode materials. The novel environment-friendly secondary aluminum battery with high energy is provided, preparation processes of the cathode active material, the negative pole and the electrolyte are free of pollution, the preparation cost is low, the technology is simple, and the prepared secondary aluminum battery is high in energy density and good in cycle performance and has good safety performance and great application prospect.

Description

technical field [0001] The invention relates to the technical field of electrochemistry, in particular to a rechargeable aluminum-sulfur battery and a preparation method thereof. Background technique [0002] The development of modern science and technology, the shortage of energy and the increasing emphasis on environmental protection require rechargeable batteries with high energy density, low price, abundant resources, safe use, and environmental friendliness. Metal aluminum is a high-energy carrier as the negative electrode of the battery, with a theoretical specific capacity of 2980mAh / g, second only to lithium (3870mAh / g); and a volume specific capacity of 8050mAh / cm 3 , 4 times that of lithium, higher than all other metal materials, and its redox potential is very low -2.35V (vsSHE), it is an ideal battery negative electrode material. Aluminum battery is one of the batteries with the highest energy density, and it has low environmental pollution, abundant raw materia...

AI Technical Summary

Problems solved by technology

[0003] The air electrode is used as the positive electrode. Since the oxygen is obtained from the outside, the theoretical energy density of the aluminum-air battery can reach 8100Wh / Kg. The energy density is only 350Wh / kg. This is due to the severe corrosion of the aluminum electrode in the aqueous solution electrolyte, and at the same time a large amount of waste heat is generated, resulting in power loss. The main reactions are as follows: (1) There is a strong bond between the aluminum alloy and oxygen In the air and aqueous solution, a dense passivation oxide film is formed on the surface, so that the electrode potential of aluminum in neutral solution cannot reach the theoretical electrode potential, and the actual working potential of aluminum is much lower than the theoretical value. , and also cause 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, which makes the utilization rate of the electrode low and wet storage poor performance

(3) Aluminum has a large self-corrosion in alkaline solution, and it is prone to serious hydrogen evolution reaction with the medium, which reduces the utilization rate of the electrode and affects the normal operation of the battery

(4) In alkaline medium, the aluminum anode flow reaction and corrosion reaction products are colloidal Al(OH)3, which not only reduces the conductivity of the electrolyte but also increases the polarization of the aluminum anode, which deteriorates the performance of the aluminum battery

[0007] However, according to the research of Professor Cui Yi from Stanford University in the United States, due to the dissolution of the reaction product of elemental sulfur, the poor conductivity of the electrode, and the wrapping of the electronically insulating reaction product on the surface of the active material particle, the active material inside the particle fails, resulting in low utilization of the active material and Poor cycle performance restricts the commercialization of metal / sulfur secondary batteries

[0008] Recently, Manthiram et al. from the University of Texas at Austin reported an aluminum-sulfur battery with a sulfur / carbon composite positive electrode. Although the problem of poor electrode conductivity has been improved to a certain extent, there is still a problem that the battery discharge platform is only maintained at 0.75V. question

This problem seriously limits the application range of aluminum-sulfur batteries.

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