Graphene modified-carbon coated lithium iron phosphate material, preparation method thereof and solid-state lithium ion battery

Abstract

The invention relates to the field of lithium batteries, and discloses a graphene modified-carbon coated lithium iron phosphate material and a preparation method thereof, and a solid lithium ion battery, the preparation method comprises the following steps: dissolving a phosphate radical raw material, an iron salt and a lithium source in an alcoholic solution, then adding a template agent, a carbon source and an antioxidant, then adding graphene oxide, and carrying out ultrasonic dispersion, so as to obtain the graphene modified-carbon coated lithium iron phosphate material. Pouring into a reaction kettle, and carrying out hydrothermal synthesis to obtain a solid-phase material; and placing the solid-phase material in a vacuum oven for drying, and then placing the dried solid-phase material in a muffle furnace for high-temperature calcination to obtain the graphene modified-carbon coated lithium iron phosphate material. When the G / LFP / C material is applied to a solid-state battery, the transportation of electrons and lithium ions can be facilitated, and the interface impedance is reduced, so that the solid-state battery prepared from the G / LFP / C material can have excellent rate capability, electrochemical lithium storage performance and cycle performance.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to a graphene-modified-carbon-coated lithium iron phosphate material, a preparation method thereof, and a solid-state lithium ion battery. Background technique [0002] Lithium iron phosphate (LiFePO 4 ) The theoretical specific capacity of the positive electrode material is 170mA / g, and the voltage platform is 3.7V. It has good thermal stability, low moisture absorption and excellent charge-discharge cycle performance under the fully charged state, so it has become the current power, energy storage The focus of research and production development in the field of lithium-ion batteries. [0003] But, first, since LiFePO 4 The limitation of the structure of the cathode material itself will lead to LiFePO 4 Lithium-ion batteries as positive electrode materials have problems such as poor conductivity, slow diffusion rate of lithium ions, and poor charge and discharge performance unde...

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Problems solved by technology

[0003] But, first, since LiFePO 4 The limitation of the structure of the cathode material itself will lead to LiFePO 4 Lithium-ion batteries as positive electrode materials have problems such as poor conductivity, slow diffusion rate of lithium ions, and poor charge and discharge performance at low temperatures.

Secondly, as a new research and development direction of lithium-ion batteries, solid-state lithium-ion batteries mainly use electrolyte membranes to replace the electrolyte and diaphragm in liquid batteries. Although this method avoids the potential safety hazards brought by liquid solvents to batteries, it uses The solid-state electrolyte also brings interface problems to the battery, resulting in a significant drop in the electrochemical performance of the solid-state battery.

These problems restrict the LiFePO 4 Large-scale application of cathode materials in solid-state lithium-ion batteries

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