Graphene aerogel loaded lithium iron phosphate porous composite material and preparation method thereof

Abstract

The invention relates to a graphene aerogel loaded lithium iron phosphate porous composite material and a preparation method thereof. The technical scheme of the invention is as follows: the preparation method comprises the steps: adding a graphene oxide into deionized water, and carrying out stirring so as to obtain a solution I with the concentration of 2kg/m<3> to 5kg/m<3>; adding a ferric salt into the solution I in accordance with that the mass ratio of the ferric salt to the graphene oxide is 1: (0.03 to 0.3), and carrying out stirring so as to obtain a solution II; adding phosphate and a lithium salt into the solution II in accordance with that the mass ratio of the ferric salt to the phosphate to the lithium salt is 1: 1: 2, carrying out stirring, carrying out a hydrothermal reaction in a reactor, carrying out washing, carrying out freezing, and carrying out drying in a vacuum freeze drier; carrying out heat preservation for 4 to 10 hours in a tube type furnace in a protective atmosphere at the temperature of 550 DEG C to 850 DEG C, and carrying out furnace cooling, thereby preparing the graphene aerogel loaded lithium iron phosphate porous composite material. According to the graphene aerogel loaded lithium iron phosphate porous composite material and the preparation method thereof, the operation is convenient, industrial production is facilitated, the prepared product is adjustable in pore structure and particle size of lithium iron phosphate loaded on the surface of graphene, and the structural stability, cycle performance and high rate capability are excellent.

Description

technical field [0001] The invention belongs to the technical field of lithium iron phosphate cathode materials. Specifically relates to a graphene airgel-loaded lithium iron phosphate porous composite material and a preparation method thereof. Background technique [0002] With the development of society and the continuous consumption of fossil energy such as coal, oil and natural gas, environmental and energy issues have increasingly become the focus of global attention. The development of new clean energy technologies has become the development strategic goal of governments. New clean energy mainly includes solar energy, nuclear energy, ocean tidal energy, wind energy and biomass energy, etc., but these energy sources have the characteristics of discontinuity and instability. Chemical energy can realize the conversion and storage between chemical energy and electrical energy, and plays a vital role in people's daily life and production. [0003] Lithium-ion batteries ha...

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Problems solved by technology

[0004] Although LiFePO 4 Cathode materials have many advantages over other cathode materials, but there are also two main disadvantages: ①The intrinsic conductivity of the material is low, which is not conducive to the electrode reaction, especially the high-rate discharge; ②Li + The diffusion rate is slow

The two lead to poor high-rate discharge performance and low reversible specific capacity, which limits its large-scale application

At the same time, the preparation methods of porous cathode materials mainly include soft template method and hard template method, but the pyrolysis temperature of soft template agent is generally lower than that of LiFePO 4 Crystallization phase temperature, when the temperature rises to LiFePO 4 At the crystallization temperature, the decomposed soft template cannot effectively support the pore structure, causing the pores to collapse, while the hard template method requires pre-prepared templates, which makes the hard template method complicated and difficult to apply on a large scale

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