Nitrogen-doped carbon composite SnFe2O4 lithium ion battery negative electrode material as well as preparation method and application thereof

A lithium-ion battery, nitrogen-doped carbon technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve the problems of specific capacity, cycle stability decline, loss of first cycle charge and discharge capacity, material specific capacity decline, etc. Achieve the effect of good electrochemical reversibility, low production cost and improved conductivity

Active Publication Date: 2019-03-08
SOUTH CHINA NORMAL UNIVERSITY
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  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

However, there are two major defects in tin-based anode materials: 1) SnO x and Li + The conversion reaction is irreversible, resulting in a serious loss of charge and discharge capacity in the first cycle, and the Coulombic efficiency is only about 50%; 2) Metal Sn and Li + The alloying / dealloying reaction of the metal Sn will cause a huge volume expansion (up to 300%) of the metal Sn, resulting in deformation, cracking and falling off of the Sn-based material, and the deterioration of the electrical contact performance, which eventually causes a rapid decline in the specific capacity of the material.
However, tin ferrite has low conductivity and excessive volume expansion rate during the charging and discharging process of lithium-ion batteries, which will cause damage to the material structure, which will lead to a rapid decline in performance such as specific capacity and cycle stability.

Method used

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  • Nitrogen-doped carbon composite SnFe2O4 lithium ion battery negative electrode material as well as preparation method and application thereof
  • Nitrogen-doped carbon composite SnFe2O4 lithium ion battery negative electrode material as well as preparation method and application thereof
  • Nitrogen-doped carbon composite SnFe2O4 lithium ion battery negative electrode material as well as preparation method and application thereof

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preparation example Construction

[0032] A nitrogen-doped carbon-composite SnFe 2 o 4 The preparation method of lithium ion battery negative electrode material, comprises the following steps:

[0033] 1) Add the iron source and the tin source to the Tween-20 aqueous solution at the same time, stir and mix well, then add the alkali solution, fully react, separate and collect the precipitate, and obtain SnFe 2 o 4 nanoparticles;

[0034] 2) SnFe 2 o 4 Nanoparticles and dopamine hydrochloride were added to the Tris-HCl buffer, fully reacted, and then centrifuged to collect the solid product to obtain the precursor;

[0035] 3) The precursor is placed in an inert atmosphere and calcined to obtain a nitrogen-doped carbon-composite SnFe 2 o 4 Lithium-ion battery anode materials (SnFe 2 o 4 @NC).

[0036] Preferably, the molar ratio of Fe and Sn in step 1) is 1:0.5.

[0037] Preferably, the concentration of the iron source in step 1) in the Tween-20 aqueous solution is 0.02-0.5 mol / L.

[0038]Preferably, ...

Embodiment 1

[0051] A nitrogen-doped carbon-composite SnFe 2 o 4 Lithium-ion battery anode materials (SnFe 2 o 4 @NC) preparation method, comprises the following steps:

[0052] 1) 12mmol of FeCl 2 4H 2 O and 6 mmol of SnCl 2 2H 2 O was simultaneously added to 150 mL of Tween-20 aqueous solution (prepared by Tween-20 and distilled water according to the volume ratio of 1:10), fully stirred and mixed, and then added NaOH solution with a concentration of 4mol / L to the reaction solution. pH value>10, stirred at 80°C for 3h, separated and collected the precipitate, washed the precipitate with distilled water several times, dried at 60°C for 10h, and obtained SnFe 2 o 4 Nanoparticles (XRD pattern as shown in figure 1 shown);

[0053] 2) SnFe with a mass ratio of 1:0.3 2 o 4 Nanoparticles and dopamine hydrochloride were added to Tris-HCl buffer solution (pH=8.5) with a concentration of 10 mmol / L, stirred at 80°C for 4h, and the solid product was collected by centrifugation, washed wi...

Embodiment 2

[0064] A nitrogen-doped carbon-composite SnFe 2 o 4 Lithium-ion battery anode materials (SnFe 2 o 4 @NC) preparation method, comprises the following steps:

[0065] 1) 15mmol of Fe(NO 3 ) 3 9H 2 O and 7.5 mmol of SnCl 2 2H 2 O was added to 150mL Tween-20 aqueous solution (prepared by Tween-20 and distilled water according to the volume ratio of 1:25) at the same time, fully stirred and mixed, and then added NaOH solution with a concentration of 4mol / L to the reaction solution. pH value>10, stirred at 25°C for 4h, separated and collected the precipitate, washed the precipitate with distilled water several times, dried at 80°C for 6h, and obtained SnFe 2 o 4 nanoparticles;

[0066] 2) SnFe with a mass ratio of 1:0.1 2 o 4 Nanoparticles and dopamine hydrochloride were added to Tris-HCl buffer (pH=8.5) with a concentration of 10mmol / L, stirred at 25°C for 6h, and the solid product was collected by centrifugation, washed with distilled water several times, and dried at ...

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Abstract

The invention discloses a nitrogen-doped carbon composite SnFe2O4 lithium ion battery negative electrode material as well as a preparation method and an application thereof; the preparation method ofthe lithium ion battery negative electrode material comprises the following steps of 1) performing co-deposition on an iron source and a tin source under the effect of a surfactant Tween-20 to generate SnFe2O4 nanoparticles; 2) enabling the SnFe2O4 nanoparticles and dopamine hydrochloride to be reacted in a Tris-HCl buffer solution to prepare a precursor; and 3) performing calcining on the precursor in an inert atmosphere. The negative electrode material of the lithium ion battery disclosed by the invention is the nitrogen-doped carbon composite SnFe2O4 nanoparticles, and has the advantages ofbeing stable in structure, high in charge-discharge efficiency, excellent in cycle performance, high in electrochemical reversibility and the like; and the negative electrode material is simple in preparation process, low in cost and environment-friendly, is suitable for practical application of the lithium ion battery, and can realize industrial large-scale production.

Description

technical field [0001] The invention relates to a nitrogen-doped carbon composite SnFe 2 o 4 The lithium-ion battery negative electrode material and its preparation method and application belong to the technical field of lithium-ion batteries. Background technique [0002] At present, the theoretical capacity of commercialized graphite anode materials (372mAh g -1 ) is low, and the lithium ion diffusion rate is small, which has been unable to meet the development trend of high energy density and high rate charge and discharge capabilities of lithium ion batteries. Therefore, searching for new anode materials that can replace graphite has become a hot spot in the research field of lithium-ion batteries in recent years. [0003] Among many anode materials, Sn-based anode materials have higher theoretical specific capacity, such as SnO 2 (1494mAh·g -1 ), SnO (1138mAh·g -1 ), Sn (991mAh·g -1 ), and the production cost is relatively low, which is considered to be the most ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/0525
CPCH01M4/364H01M4/5825H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 关冬彩孙艳辉
Owner SOUTH CHINA NORMAL UNIVERSITY
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