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Graphene-supported silicon quantum dot negative electrode material and preparation method and application thereof

A technology of silicon quantum dots and anode materials, applied in nanotechnology for materials and surface science, battery electrodes, electrical components, etc. and other problems, to achieve the effect of good scalability, shortened diffusion distance, and improved kinetics of lithium storage.

Active Publication Date: 2016-06-01
THE NAT CENT FOR NANOSCI & TECH NCNST OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, silicon-carbon nanocomposites (such as composites of graphene and silicon nanoparticles)-based lithium-ion battery anodes, on the one hand, have poor size uniformity in the silicon component, which greatly affects the cycle stability of the designed material. (Rolesofnanosizeinlithiumreactivenanomaterialsforlithiumionbatteries, NanoToday2011,6,28); on the other hand, the preparation of this type of material mainly relies on expensive, highly dangerous gaseous silicon sources such as monosilane, or the hydrofluoric acid etching process that is not conducive to the environment, or harsh (such as , high vacuum, high temperature, etc.) energy-consuming synthesis process (Large-scalefabrication, 3Dtomography, andlithium-ionbatteryapplicationofporoussilicon, NanoLetters2014, 14, 261), the method itself seriously restricts the practical application of this type of material

Method used

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  • Graphene-supported silicon quantum dot negative electrode material and preparation method and application thereof
  • Graphene-supported silicon quantum dot negative electrode material and preparation method and application thereof
  • Graphene-supported silicon quantum dot negative electrode material and preparation method and application thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0034] (1) Mix 3-aminopropyltriethoxysilane and sodium citrate pre-dissolved in water according to a mass ratio of 5:1, then transfer to a solvothermal reaction kettle, and place it at a constant temperature of 180°C for 2 hours, Dialysis to remove unreacted raw materials to obtain uniform 3nm silicon quantum dots;

[0035] (2) After mixing uniform silicon quantum dots with graphene oxide, adjust the pH value of the solution to 3, and after further stirring, obtain silicon quantum dots supported by graphene oxide;

[0036] (3) The silicon quantum dots supported by graphene oxide were treated at 300° C. for 5 hours under a hydrogen atmosphere to prepare silicon quantum dots supported by graphene.

[0037] The obtained graphene-supported silicon quantum dots, the binder polyvinylidene fluoride (PVDF), and the conductive agent acetylene black are uniformly mixed in N-methylpyrrolidone (NMP) to prepare a slurry, which is then coated on On the copper foil current collector, after ...

Embodiment 2

[0040](1) Mix triphenylsilylamine and sodium borohydride pre-dissolved in water according to a mass ratio of 1:1, then transfer it to a solvothermal reaction kettle, and place it at a constant temperature of 400°C for 0.5 hours, then dialyze to remove untreated The raw material for the reaction is to obtain uniform 30nm silicon quantum dots;

[0041] (2) After mixing uniform silicon quantum dots with graphene oxide, adjust the pH value of the solution to 1, and after further stirring, obtain silicon quantum dots supported by graphene oxide;

[0042] (3) The silicon quantum dots supported by graphene oxide were treated at 900° C. under an argon atmosphere for 0.5 hours to prepare silicon quantum dots supported by graphene.

[0043] Subsequent tests were as in Example 1. At a current density of 10A / g, the graphene-supported silicon quantum dot still has a specific capacity as high as 655mAh / g; after 300 cycles at a current density of 2A / g, the capacity retention rate can reach ...

Embodiment 3

[0045] (1) Mix divinyltriaminopropyltrimethoxysilane and sodium sulfite pre-dissolved in water according to a mass ratio of 10:1, then transfer it to a solvothermal reaction kettle, place it at a constant temperature of 120°C for 12 hours, and dialyze Remove unreacted raw materials to obtain uniform 15nm silicon quantum dots;

[0046] (2) After mixing uniform silicon quantum dots with graphene oxide, adjust the pH value of the solution to 7, and after further stirring, obtain silicon quantum dots supported by graphene oxide;

[0047] (3) The silicon quantum dots supported by graphene oxide were treated at 150° C. for 12 hours under a mixed atmosphere of argon and hydrogen to prepare silicon quantum dots supported by graphene.

[0048] Subsequent tests were as in Example 1. At a current density of 20A / g, the graphene-supported uniform ultra-small silicon quantum dots still have a specific capacity of 595mAh / g; after 450 cycles at a current density of 2A / g, the capacity retenti...

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Abstract

The invention relates to a graphene-supported silicon quantum dot negative electrode material and a preparation method and application thereof. The preparation method comprises the following steps of (1) synthesizing silicon quantum dots which are highly uniform in size by a solvothermal method based on an organic silicon precursor; (2) highly uniformly loading the silicon quantum dots on graphene oxide by a non-covalent self-assembly method to prepare graphene oxide supported silicon quantum dots; and (3) reducing the graphene oxide by a thermal treatment method to prepare the graphene-supported silicon quantum dot negative electrode material. The preparation method has the advantages of low cost, simplicity in process, controllability and low energy consumption, and can be scalable, and moreover, the obtained graphene-supported silicon quantum dot negative material is high in charging / discharging and rate performance and very stable in circulation.

Description

technical field [0001] The invention belongs to the field of electrode materials, and in particular relates to a graphene-supported silicon quantum dot negative electrode material and a preparation method and application thereof. Background technique [0002] Lithium-ion batteries are ideal power sources for portable electronic devices and electric vehicles. The development of new lithium-ion battery electrodes with high energy density, high power density, and long cycle life is currently a hot spot in the field of lithium-ion battery research. Silicon is a new type of negative electrode material for lithium-ion batteries. Its lithium storage reaction voltage platform is low, and its theoretical capacity is extremely high (4200mAh / g), which is much higher than the current marketed graphite negative electrode. Moreover, silicon is abundant in nature. , is a class of lithium-ion battery anode materials with great development prospects. However, silicon itself has low electron...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/62B82Y30/00
CPCY02E60/10
Inventor 李祥龙王斌智林杰
Owner THE NAT CENT FOR NANOSCI & TECH NCNST OF CHINA
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