Micro-nano-structure anode material for Li-air battery and preparation method of micro-nano-structure anode material

Abstract

The invention relates to a micro-nano-structure anode material for a Li-air battery and a preparation method of the micro-nano-structure anode material. The preparation method comprises the following steps of: preparation of hollow composite precursor fibers through electrostatic spinning by blending a metal nitride catalyst precursor with a high-carbon polymer in an organic solvent, preprocessing of the precursor fiber material, nitridation of complex fibers, and pore-forming and pore-expansion through activation. The preparation method is simple in technique and convenient to operate and is easy to realize the uniform distribution of nanoscale catalyst particles in hollow carbon fibers. A prepared anode material tube is hollow internally, a plurality of holes are formed on the wall of the tube, and metal nitride catalysts are uniformly distributed in the three-dimensional holes of the wall of the tube, so that high specific surface area provides a sufficient place for the reaction of the battery, and the hollow pore passage in the tube can ensure an oxygen diffusion channel to be smooth and has good ion transport capacity and electrical conductivity. According to the invention, the charge-discharge capacity of the Li-air battery can be improved effectively, the power multiplying performance and the power density of the Li-air battery can be improved, the internal resistance of the battery can be reduced, and the charge-discharge polarization can be lessened through the uniform distribution of the nanoscale metal nitride, therefore, the micro-nano-structure anode material has good industrialization prospect.

Description

technical field [0001] The invention belongs to the field of new energy, and relates to a cathode material for a lithium-air battery and a preparation method thereof. Background technique [0002] With the development of human society, problems such as energy shortage and environmental pollution have become increasingly prominent, and people's understanding and requirements for chemical power sources have become higher and higher, prompting people to continuously explore new energy storage systems based on chemical power sources. Lithium metal-based batteries have led the development of high-performance chemical power sources in recent decades. With the successful commercialization of lithium-ion batteries, countries around the world are stepping up research on lithium-ion power batteries for vehicles. However, due to factors such as energy density, safety, and price, conventional lithium-ion batteries cannot meet the requirements of electric vehicles as a power source. ...

AI Technical Summary

Problems solved by technology

[0004] At present, the main problems restricting the development of lithium-air batteries are: the product is insoluble in the organic electrolyte during the discharge process, easy to deposit on the positive electrode, blocking the transmission channel of oxygen and serious polarization problems during the charge and discharge process.

Wu Xu (Journal of The Electrochemical Society, 157(2010) A294-A297) etc. used KB carbon as the catalyst carrier, and the catalyst MnO 2 Mixed with activated carbon ball milling to make the positive electrode, the voltage polarization of the material has been improved to a certain extent, but the pores are easily blocked during the discharge process, and the capacity is small; Li Jiaxin et al. Using carbon nanotubes as a carrier to support MnO by impregnation method 2 Catalyst, the discharge capacity is increased to 1768mAh / g, and the charging platform has been reduced. Due to the severe agglomeration and winding of carbon tubes, the catalyst and carbon tubes cannot be uniformly recombined, and the catalyst particle size is large, which cannot exert good electrochemical performance; Taek Han Yong ( Nanoscale Research Letters "Nanoscale Research Letters" 7(2012)) et al. hydrothermally prepared Co 3 o 4 Composite to the surface of carbon tubes as a positive electrode material, it shows good discharge capacity and low overpotential, but when charging and discharging at a high rate, the battery capacity drops sharply; Zhou Haoshen (American Chemical Society "ACS Nano" 5 (2011 ) 3020-3026) etc. use graphene as a carrier, not only the discharge capacity has been greatly improved, but also because of the specific microstructure of graphene, it has high reactivity and shows a good catalytic effect, but graphene is complex The synthesis process and expensive cost hinder its promotion and application in lithium-air batteries

[0007] Chinese patent CN 102240574A discloses a catalyst composed of a transition metal complex and a carbon black carrier. The lithium-air battery prepared by using this catalyst exhibits good catalytic activity and stability, but the charging and discharging of the battery under high current density The behavior is not ideal, and the hydrothermal method used cannot control the morphology of the catalyst; Chinese patent CN 102306808A discloses a catalyst for air electrodes that uses manganese salts and silver salts as raw materials, carbon materials as carriers, and ball milling. The preparation method and The process is simple and easy to operate, but the catalyst is not evenly distributed on the carrier, resulting in insignificant catalytic effect

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