Micro/nano structured cathode material for lithium air batteries

Abstract

The invention discloses a micro / nano structured cathode material for lithium air batteries. The cathode material comprises hollow porous composite fibers, is obtained by compounding catalyst nano particles used for lithium air battery positive electrode reaction with a hollow micron-sized carbon fiber carrier, the carbon fiber tube wall comprises a plurality of nano pores which are interconnected, and the catalyst nano particles are dispersedly loaded on the carbon fiber tube wall and in the pores. The prepared cathode material can provide sufficient active substance reaction zones, simultaneously the porous structure of the tube wall increases the reaction activity of the active substance, and the hollow structure in the tube guarantees the unblocked delivery channel of oxygen. According to the invention, the cathode material disclosed herein has a structure of hollow in the tube and porous on the tube wall; the micro / nano structured cathode material formed by compounding the nano catalyst, thus the material has excellent electrical conductivity, can effectively raise the charge and discharge capacity of the lithium air batteries, reduce the polarization of charge and discharge, raise the high rate discharge capability and power density of the lithium air batteries are raised, the battery inner resistance is reduced, thus the material disclosed herein is an ideal cathode material.

Description

technical field [0001] The invention belongs to the field of new energy, and relates to a micro-nano structure cathode material for a lithium-air battery. 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. [0003] A lit...

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, blocks the transmission channel of oxygen, and is severely polarized during the charge and discharge process.

Xia Yongyao et al. (Electrochemistry Communications "Electrochemistry Communications" 11(2009) 1127-1130) proposed to use ordered mesoporous carbon (MCF-F) as a carrier, and believed that the discharge products would not accumulate in the micropores during the reaction, and the mesopores Increase is conducive to improving the capacity of the positive electrode, but the specific surface area of ​​this structural material is low, only 824m 2 / g, the effect is not ideal after loading the catalyst

Zhang G.Q. et al. (Journal of The Electrochemical Society "157 (2010) A953-A956) used carbon paper (SWNT / CNF) as a carrier, at 0.1mA / cm 2 Under the current density, when the air electrode is thinner, the discharge capacity reaches 2500mAh / g. When the air electrode is thicker, the phenomenon that the discharge product blocks the oxygen diffusion channel still exists, which directly leads to the decrease of the discharge capacity; Li Jiaxin et al. (Electrochemical Communications " Electrochemistry Communications" 13 (2011) 698-700) uses 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 size of the catalyst particles is large, which cannot exert good electrochemical performance; Zhou Haoshen (USA 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 the high reactivity due to the specific microstructure of graphene, showing great Good catalytic effect, but the complex synthesis process and expensive cost of graphene hinder its promotion and application in lithium-air batteries

[0007] Chinese patent CN 102208653A discloses an air cathode material with a conjugated conductive polymer as a carrier. Although it has a high specific surface area and good conductivity, the product still partially blocks the oxygen diffusion channel.

Images