A kind of sulfur cathode material with core-shell structure and preparation method thereof, lithium-sulfur battery positive electrode sheet and lithium-sulfur battery

A technology of sulfur cathode material and core-shell structure, which is applied in the field of lithium-sulfur batteries, can solve the problems of poor conductivity, capacity loss, and reduction of preparation costs of sulfur cathodes, and achieve improved rate performance, cost reduction, large specific surface area and porosity. Effect

Active Publication Date: 2020-12-04
NAT UNIV OF DEFENSE TECH
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  • Description
  • Claims
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Problems solved by technology

[0005] The present invention provides a sulfur positive electrode material with a core-shell structure and a preparation method thereof, a lithium-sulfur battery positive pole piece and a lithium-sulfur battery, which are used to overcome the problems of the very poor conductivity of the sulfur positive electrode and the discharge product lithium polysulfide in the prior art The shuttle effect caused by dissolution and diffusion will cause defects such as capacity loss and cycle attenuation, so that the sulfur cathode has excellent conductivity and can prevent the dissolution of polysulfides in the electrolyte, while significantly reducing the preparation cost

Method used

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  • A kind of sulfur cathode material with core-shell structure and preparation method thereof, lithium-sulfur battery positive electrode sheet and lithium-sulfur battery
  • A kind of sulfur cathode material with core-shell structure and preparation method thereof, lithium-sulfur battery positive electrode sheet and lithium-sulfur battery
  • A kind of sulfur cathode material with core-shell structure and preparation method thereof, lithium-sulfur battery positive electrode sheet and lithium-sulfur battery

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preparation example Construction

[0048] The present invention also proposes a method for preparing a sulfur cathode material, comprising the following steps:

[0049] S1: with Fe 2 o 3 Nanocubes were used as templates, and the Fe 2 o 3 The nanocube surface is coated with a layer of polydopamine polymer (PDA) to form Fe 3 o 4 @PDA nanocube, and Fe under inert atmosphere 3 o 4 @PDA nanocubes are sintered at high temperature to obtain carbon-coated ferric oxide nanocubes, denoted as Fe 3 o 4 @C;

[0050] Preferably, S1 specifically includes:

[0051] S11: Fe 2 o 3 Nanocubes were dispersed in deionized water and sonicated until uniformly dispersed; control of Fe 2 o 3 The ratio relationship between nanocubes and deionized water to ensure Fe 2 o 3 Nano cubes can be dispersed evenly;

[0052] S12: Add buffer and dopamine hydrochloride, stir, collect by centrifugation, and dry to obtain polydopamine-coated Fe 3 o 4 Nanocubes, denoted as Fe 3 o 4 @PDA; Dopamine hydrochloride will polymerize under ...

Embodiment 1

[0070] This embodiment provides a sulfur cathode material, the sulfur cathode material is a S / Fe core-shell structure 2 N@C composite nanocage, with carbon as the outer shell and iron nitride as the inner core; the sulfur cathode material also includes sulfur element, which is distributed on the inner wall of the outer shell and the surface of the inner core, denoted as S / Fe 2 N@C; the S / Fe 2 The size of N@C is between 400nm and 500nm.

[0071] This embodiment also provides a method for preparing a sulfur cathode material, comprising the following steps:

[0072] S1: carbon-coated ferric oxide (Fe 3 o 4 @C) preparation of nanocubes;

[0073] Fe with a particle size of 500nm 2 o 3 Nanocubes as templates (morphology such as Figure 1a shown), using the in-situ coating method on Fe 2 o 3 The surface of the nanocube is uniformly coated with a layer of polydopamine polymer, and sintered at high temperature under an argon atmosphere to obtain carbon-coated iron tetroxide (Fe...

Embodiment 2

[0086] This embodiment provides a lithium-sulfur battery positive pole piece and a lithium-sulfur battery. The positive electrode material of the lithium-sulfur battery positive pole piece is the sulfur positive electrode material S / Fe described in Example 1. 2 N@C, the positive pole piece of the lithium-sulfur battery is the positive pole piece of the lithium-sulfur battery.

[0087] The characterization results of the lithium-sulfur battery described in this example are as follows Figure 4a , Figure 4b , Figure 4c , Figure 4d , Figure 5a , Figure 5b shown.

[0088] The specific preparation method is as follows:

[0089] (1) Preparation of positive pole piece. Weigh the sulfur cathode material S / Fe according to the mass ratio of 80:12:8 2 N@C, superconducting carbon, and binder LA133 were placed in a high-energy ball milling tank. According to the ratio of LA133 / deionized water with a mass ratio of 1:20, deionized water was weighed and added to the high-energy b...

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Abstract

The invention discloses a sulfur cathode material with a core-shell structure and a preparation method thereof, a lithium-sulfur battery cathode piece and a lithium-sulfur battery. The material is thecore-shell structure, carbon is used as a shell, and iron nitride is used as an inner core. The material further comprises elemental sulfur which is distributed on the inner wall of the shell and thesurface of the inner core. The preparation method comprises the following steps of: taking Fe2O3 nanocubes as a template, preparing Fe3O4@C by in-situ coating and high-temperature carbonization; forming a core-shell structure through ultrasonic acid etching; performing sintering in an ammonia atmosphere to form a core-shell structure by taking carbon as a shell and taking iron nitride as an innercore; and finally, infiltrating elemental sulfur into Fe2N-C through melt diffusion to obtain the sulfur cathode material. The carbon shell in the sulfur cathode material provided by the invention has high conductivity, the iron nitride core has strong chemical adsorption effect and electrocatalytic activity on polysulfide lithium, and the cathode piece and the lithium-sulfur battery prepared from the material have excellent battery cycle performance and rapid charging / discharging performance; the preparation method is simple in process, low in cost and easy to implement.

Description

technical field [0001] The invention relates to the technical field of lithium-sulfur battery preparation, in particular to a sulfur cathode material with a core-shell structure and a preparation method thereof, a lithium-sulfur battery cathode sheet and a lithium-sulfur battery. Background technique [0002] With the rapid development of portable electronic devices and electric vehicles, people's demand for secondary power supplies with high energy density is increasing day by day. However, the actual energy density of commercial lithium-ion batteries is relatively low (generally 150-200Wh / kg), which is difficult to meet the demand for higher energy density (>300Wh / kg) in future high-end electronic equipment and electric vehicles. For this reason, people turn their attention to the new secondary battery system in order to obtain higher energy density. [0003] Among the currently known positive electrode materials, sulfur has a high theoretical specific capacity (1675mA...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/58H01M4/62H01M10/052C01B32/05
CPCC01B32/05H01M4/364H01M4/38H01M4/58H01M4/625H01M10/052H01M2004/028Y02E60/10
Inventor 孙巍巍李宇杰郑春满谢凯
Owner NAT UNIV OF DEFENSE TECH
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