a lifepo 4 Solvothermal Assisted Preparation of @c/rgo Hierarchical Composite Microspheres

A composite microsphere, solvothermal technology, applied in nanotechnology, nanotechnology, structural parts, etc. for materials and surface science, can solve the problem of increasing material production cost and process complexity, low electrical conductivity, and unsuitable scale To solve the problems of popularization and popularization of chemical technology, it can achieve the effect of excellent electrochemical lithium storage performance and improve electronic conductivity.

Active Publication Date: 2020-08-07
JILIN UNIV
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

But LiFePO 4 The material also has some disadvantages and deficiencies: compared to LiCoO 2 and LiMn 2 o 4 and other metal oxide cathode materials, LiFePO 4 Intrinsic conductivity (-9 S cm -1 ) and ion diffusion rate (10 -12 ~10 -14 cm 2 the s -1 ) are relatively low, so it cannot be applied in power batteries with relatively demanding technical requirements without modification
Traditional hydrothermal / solvothermal synthesis processes mostly use expensive and active divalent Fe 2+ Salt is used as an iron source, and additional reducing agents or protective gas are required to avoid Fe 2+ Oxidation of ions during the reaction process, and sometimes a second carbon coating step is required. These additional steps invisibly increase the production cost and process complexity of the material, so it is not suitable for large-scale promotion and popularization

Method used

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  • a lifepo <sub>4</sub> Solvothermal Assisted Preparation of @c/rgo Hierarchical Composite Microspheres
  • a lifepo <sub>4</sub> Solvothermal Assisted Preparation of @c/rgo Hierarchical Composite Microspheres
  • a lifepo <sub>4</sub> Solvothermal Assisted Preparation of @c/rgo Hierarchical Composite Microspheres

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] (1) 1.153g H 3 PO 4 Aqueous solution (H 3 PO 4 The mass fraction is 85%), 0.84g LiOH·H 2 O, 4.04gFe(NO 3 ) 3 9H 2 O and 0.55g resorcinol were sequentially added to 10g, the concentration was 2.0mg mL -1 In the graphene oxide (GO) aqueous solution, fully stir;

[0031] (2) Add 10 g of methanol solution containing 0.81 g of formaldehyde solution (the mass fraction of formaldehyde is 37%) to the solution obtained in step (1), and stir well;

[0032] (3) The mixed solution in step (2) was transferred to a reaction kettle, sealed, and crystallized under autogenous pressure at 180° C. with constant temperature stirring (600 rpm) for 6 hours. After the reaction was completed, the product was suction filtered, washed with deionized water, and air-dried in an oven at 70°C for 12 hours to obtain LiFePO 4 OH@RF / GO powder precursor;

[0033] (4) LiFePO obtained in step (3) 4 OH@RF / GO powder precursor placed in Ar / H 2 (H 2 The volume fraction is 6%) in a tube furnace wi...

Embodiment 2

[0035] (1) 1.153g H 3 PO 4 Aqueous solution (H 3 PO 4 The mass fraction is 85%), 0.84g LiOH·H 2 O, 4.04gFe(NO 3 ) 3 9H 2 O and 0.66g resorcinol were sequentially added to 10g, the concentration was 5.0mg mL -1 In the graphene oxide (GO) aqueous solution, fully stir;

[0036] (2) Add 10 mL of methanol solution containing 1.215 g of formaldehyde aqueous solution (the mass fraction of formaldehyde is 37%) to the solution in step (1), and stir well;

[0037] (3) The mixed solution in step (2) was transferred to a reaction kettle, sealed, and crystallized under autogenous pressure at 170° C. with constant temperature stirring (450 rpm) for 8 hours. After the reaction was completed, the product was suction filtered, washed with deionized water, and dried in an oven at 80°C for 10 hours to obtain LiFePO 4 OH@RF / GO powder precursor;

[0038] (4) LiFePO obtained in step (3) 4 OH@RF / GO powder precursor placed in Ar / H 2 (H 2 The volume fraction is 6%) in a tube furnace with ...

Embodiment 3

[0040] (1) 1.153g H 3 PO 4 Aqueous solution (H 3 PO 4 The mass fraction is 85wt.%), 1.53g CH 3 COOLi·2H 2 O, 4.04g Fe(NO 3 ) 3 9H 2 O and 0.55g resorcinol were sequentially added to 10g, the concentration was 3.0mg mL -1 In the graphene oxide (GO) aqueous solution, fully stir;

[0041] (2) Add 10 g of methanol solution containing 1.215 g of formaldehyde solution (the mass fraction of formaldehyde is 37wt.%) to the solution of step (1), and stir well;

[0042] (3) The mixed solution in step (2) was transferred to a reaction kettle, sealed, and crystallized under autogenous pressure at 200° C. with constant temperature stirring (600 rpm) for 5 hours. After the reaction was completed, the product was suction filtered, washed with deionized water, and dried in an oven at 80°C for 12 hours to obtain LiFePO 4 OH@RF / GO powder precursor;

[0043] (4) LiFePO obtained in step (3) 4 The OH@RF / GO powder precursor was placed in a tube furnace with an Ar atmosphere at 3°C ​​min ...

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Abstract

The invention discloses a thermal-assisted preparation method of a solvent of a LiFePO4@C / rGO (reduced graphene oxide) multi-stage composite microsphere, which belongs to the technical field of electrochemical energy storage materials. In the thermal-assisted preparation method, Fe<3+> salt serves as an iron source, and a LiFePO4OH multi-stage composite microsphere LiFePO4OH@RF / GO modified by RF (resorcinol-formaldehyde resin) and GO (formaldehyde resin) is prepared in situ synthesis by a one-step mixed solvent-thermal method. The composite microsphere is further translated into a LiFePO4 / C multi-stage composite microsphere LiFePO4@C / rGO modified by rGO by high-temperature carbon thermal reduction treatment under an effect of protecting gas, the tap density is 1.3g / cm<3>; due to nanoscale primary particles, the sufficient activity contact area with an electrode / electrolyte is ensured; in addition, due to the loaded large-area rGO nanosheets, the electronic conductivity inside the microsphere or between every two adjacent microspheres is greatly improved; therefore, the material has excellent electrochemical lithium storage performance, so that the material has the potential application prospect in high-energy / power lithium-ion batteries.

Description

technical field [0001] The invention belongs to the technical field of electrochemical energy storage materials, in particular to a LiFePO 4 Solvothermal-assisted preparation of @C / rGO multi-level composite microspheres. Background technique [0002] With the increasing concept of energy saving, emission reduction and environmental protection, people gradually realize the importance of developing new green vehicles (such as pure electric vehicles and hybrid electric vehicles), and at the same time, more and more requirements are put forward for the performance indicators of large power batteries. High technical requirements. Compared with early storage batteries such as lead-acid, nickel-cadmium, and nickel-metal hydride batteries, lithium-ion batteries (LIBs) have many technical advantages: high single output voltage, high power / energy density, low self-discharge efficiency, long cycle life, and environmental protection. It is friendly and has no memory effect, etc., so i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/366H01M4/5825H01M4/625H01M10/0525H01M2004/021Y02E60/10
Inventor 张宗弢王洪宾王润伟刘丽佳
Owner JILIN UNIV
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