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Lithium titanate silicon-based composite negative electrode material and preparation method thereof

A negative electrode material, lithium titanate technology, applied in the direction of negative electrode, battery electrode, active material electrode, etc., can solve the problems of large expansion rate, small volume expansion, and low cycle life of the pole piece, and achieve high safety and small expansion , rate charge and discharge performance and excellent safety performance

Pending Publication Date: 2020-11-06
SHAANXI COAL & CHEM TECH INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to solve the problems existing in the prior art, the present invention provides a lithium titanate-silicon-based composite negative electrode material and its preparation method, which can relieve silicon powder by utilizing the zero-strain characteristic of lithium titanate while maintaining the high specific capacity of silicon. The volume effect negative electrode material overcomes the problems of large expansion rate, poor stability and low cycle life of the existing silicon negative electrode material, and the obtained lithium titanate silicon-based composite negative electrode material has excellent cycle performance and rate charge and discharge performance. The expansion is small, which can well meet the needs of commercial customers for high life and long cycle

Method used

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  • Lithium titanate silicon-based composite negative electrode material and preparation method thereof
  • Lithium titanate silicon-based composite negative electrode material and preparation method thereof
  • Lithium titanate silicon-based composite negative electrode material and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0035] Evenly disperse silicon powder and lithium titanate with a mass ratio of 60:40 in ethanol, then add 20% dispersant, the dispersant is sodium dodecylbenzenesulfonate, and the above mixed solution is wetted in a nano grinder. Grinding by using 0.2mm zirconia beads as the grinding medium, and grinding for 10h at a speed of 1500rpm to obtain a suspension of nano-silicon / nano-lithium titanate with a median particle size of 100nm;

[0036] Add 10% pore-forming agent to the nano-silicon / nano-lithium titanate suspension, the pore-forming agent is polyvinylpyrrolidone, stir at a high speed for 1 hour, and the stirring speed is 1500rpm. After the stirring is completed, carry out spray drying. 120°C, the outlet temperature is 80°C, and the rotation speed of the atomizing disc is 15000rpm, thus obtaining the first precursor;

[0037] The first precursor is placed in a rotary furnace for chemical vapor deposition. Nitrogen gas is fed into the rotary furnace at a flow rate of 2L / min....

Embodiment 2

[0040] Evenly disperse silicon powder and lithium titanate with a mass ratio of 5:95 in ethanol, then add 1% dispersant, the dispersant is sodium dodecylbenzenesulfonate, and the above mixed solution is wetted in a nano grinder. Grinding using the grinding medium, using 0.05mm zirconia beads as the grinding medium, grinding for 24 hours at a speed of 1500rpm to obtain a suspension of nano-silicon / nano-lithium titanate with a median particle size of 30nm;

[0041] Add 5% pore-forming agent to the nano-silicon / nano-lithium titanate suspension, the pore-forming agent is a mixture of glucose and sucrose, stir at a high speed for 2 hours, and the stirring speed is 2000rpm. After the stirring is completed, spray dry. The temperature is 120°C, the outlet temperature is 75°C, and the rotation speed of the atomizing disc is 15000rpm, thus obtaining the first precursor;

[0042] The first precursor was placed in a rotary furnace for chemical vapor deposition. Helium was fed into the rot...

Embodiment 3

[0045] Evenly disperse silicon powder and lithium titanate with a mass ratio of 95:5 in the mixed solution of ethanol and propanol, then add 5% dispersant, the dispersant is polyoxyethylene fatty acid ester, and the above mixed solution is nano-grinded Carry out wet grinding in the machine, the grinding medium is 4mm zirconia beads, and grind for 5h at a speed of 500rpm to obtain a nano-silicon / nano-lithium titanate suspension with a median particle size of 200nm;

[0046] Add 15% pore-forming agent to the nano-silicon / nano-lithium titanate suspension, the pore-forming agent is polyvinylpyrrolidone, stir at a high speed for 3 hours, and the stirring speed is 1000rpm. After the stirring is completed, carry out spray drying. 200°C, the outlet temperature is 120°C, and the rotation speed of the atomizing disc is 15000rpm, thus obtaining the first precursor;

[0047] The first precursor is placed in a rotary furnace for chemical vapor deposition. Nitrogen gas is fed into the rotar...

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Abstract

The invention discloses a lithium titanate silicon-based composite negative electrode material and a preparation method thereof. The material comprises an inner core and an outer shell coating the inner core, and the core-shell type lithium titanate silicon-based composite negative electrode material is formed. The inner core is composed of an organic carbon matrix filled and / or coated porous nanosilicon / nano lithium titanate material, and the outer shell is an organic pyrolytic carbon layer. The preparation method of the lithium titanate silicon-based composite negative electrode material comprises the following steps: mixing and ball-milling silicon powder and lithium titanate; then carrying out spray drying, then carrying out gas-phase carbon coating, solid-phase carbon coating and crushing to obtain lithium titanate silicon-based composite material. The lithium titanate silicon-based composite negative electrode material has the advantages that the lithium titanate silicon-based composite negative electrode material is excellent in cycle performance and rate charge and discharge performance and low in volume expansion, and accordingly requirements of commercial customers on long service lives and long cycles can be effectively met.

Description

technical field [0001] The invention belongs to the field of negative electrode materials for lithium ion batteries, and relates to a lithium titanate-silicon-based composite negative electrode material and a preparation method thereof. Background technique [0002] Under the general trend of global energy conservation and emission reduction, people pay more and more attention to new energy sources, which accelerates the development and technological progress of new energy materials, and the exploration and research of negative electrode materials in new electrode materials is particularly important. [0003] At present, the anode material that has attracted much attention is silicon anode material, because of its theoretical specific capacity (4200mAh / g), which is much higher than that of graphite anode, and has good safety performance. However, serious volume changes occur during the charging and discharging process, causing the active material to expand and rupture, and e...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/38H01M4/485H01M4/62H01M10/0525B82Y40/00
CPCB82Y40/00H01M4/364H01M4/386H01M4/485H01M4/625H01M4/628H01M10/0525H01M2004/027Y02E60/10
Inventor 张长安曹新龙曹国林白杨芝王夏阳田占元
Owner SHAANXI COAL & CHEM TECH INST
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