porous carbon-fe 3 o 4 Nanomaterials, air cathode materials and lithium-air batteries

Abstract

The present invention relates to a porous carbon-Fe 3 o 4 The air positive electrode material is prepared as follows: iron nitrate, aspartic acid and NaOH solid are dissolved in deionized water to obtain a mixed solution a; the mixed solution a is transferred to a reactor for hydrothermal reaction to obtain a yellow precipitate The solution of the substance; the solution with the yellow precipitate is centrifuged, left still, and dried to obtain the precursor MOF material; the precursor MOF material is calcined to obtain the porous carbon-Fe 3 o 4 nanomaterials. An air cathode material, comprising a porous current collector and a slurry layer coated on the porous current collector, the slurry layer contains porous carbon-Fe 3 o 4 nanomaterials. A lithium-air battery includes an air cathode material. Porous carbon-Fe obtained by hydrothermal and calcination 3 o 4 Nanomaterials have a large specific surface area, can provide more catalytic active sites, have better catalytic activity, and can provide more space for the accumulation of discharge products of lithium-air batteries.

Description

technical field [0001] The invention relates to the field of electrochemical energy, in particular to a porous carbon-Fe 3 o 4 Nanomaterials, air cathode materials and lithium-air batteries. Background technique [0002] With the increasing development of science and technology, people's life has been greatly improved. But at the same time, energy and environmental problems are becoming more and more serious, especially the fossil energy has been depleted day by day, and people urgently need to find new energy to replace it. In the past two decades, secondary batteries such as lithium-ion batteries with graphite as the negative electrode have been greatly developed, and are widely used in portable electronic products and electric vehicles. However, the energy density of lithium-ion batteries using graphite as the negative electrode has gradually approached the theoretical value (300Wh / kg), which can no longer meet the requirements of the gradual expansion of the current e...

AI Technical Summary

Problems solved by technology

Therefore, researchers have turned their attention to lithium-air batteries. However, so far, the practical application of lithium-air batteries still faces severe challenges, such as low Coulombic efficiency, low rate performance and short cycle life.

In order to improve the performance of lithium-air batteries and promote their practical application, researchers have made a lot of efforts in finding new electrolytes (ionic liquids, solid electrolytes, etc.), protecting lithium negative electrodes, and designing reasonable air positive electrode structures. As one of the main places for charging and discharging, its structure has a profound impact on the performance of lithium-air batteries. Lithium-air batteries generate insoluble and insulating Li during discharge. 2 o 2 , LiOH, Li 2 CO 3 Such products are deposited on the surface of the air positive electrode, blocking the transmission path of oxygen and electrons, resulting in battery capacity decay

[0004] 3d-electron transition metal oxides such as Mn, Co, Ni, Fe, etc. show good catalytic performance for oxygen reduction and oxygen evolution reactions in non-aqueous electrolytes, but the poor conductivity of transition metal oxides leads to their use in lithium air Catalytic materials for the positive electrode of the battery will increase the resistance of electron transport and eventually cause the polarization of the electrode to increase. Therefore, a catalytic material with good electrical conductivity and excellent catalytic activity is used for the positive electrode material of the air to catalyze and reduce the overpotential of charge and discharge, and alleviate The decomposition of the electrolyte can alleviate the side reactions of the positive electrode and the passivation of the cathode, thereby improving the performance of the lithium-air battery

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