Preparation method for lithium-ion battery cathode material with high initial coulomb efficiency

A lithium-ion battery and negative electrode material technology, which is applied to battery electrodes, circuits, electrical components, etc., can solve the problems of limiting the utilization rate of positive electrode materials, shedding, and low Coulombic efficiency, and achieve the effect of improving cycle capacity retention and simple methods

Active Publication Date: 2013-08-21
ZHEJIANG UNIV
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  • Abstract
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  • Application Information

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Problems solved by technology

[0004] Among the currently developed negative electrode materials for lithium-ion batteries, silicon-based materials are favored for their low potential and high capacity. However, during the lithium storage / discharge process, the huge volume change leads to serious powdering and shedding of the silicon negative electrode. , the cycle capacity declines rapidly, which cannot meet the requirements of practical applications
[0005] SiO can form attached to Li after the first lithium intercalation 4 SiO 4 Nano-Li-Si alloys on the substrate, where Li 4 SiO 4 As a buffer substance, it effectively alleviates the volume change during the Li-Si alloy intercalation and deintercalation process, so that the SiO anode exhibits good cycle stability, but the SiO anode material intercalates lithium for the first time to form Li 4 SiO 4 The phase process is irreversible, which leads to a very large irreversible capacity of the system material, which makes the first Coulombic efficiency of the material extremely low, severely limits the utilization rate of the positive electrode material in the battery, and reduces the actual capacity of the lithium-ion battery.

Method used

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  • Preparation method for lithium-ion battery cathode material with high initial coulomb efficiency
  • Preparation method for lithium-ion battery cathode material with high initial coulomb efficiency
  • Preparation method for lithium-ion battery cathode material with high initial coulomb efficiency

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Effect test

Embodiment 1～3

[0032] In a vacuum glove box, LiH and SiO were weighed and loaded into a ball mill jar at a molar ratio of 0.4:1, 0.67:1, and 1:1, respectively. The ball mill jar containing the mixture is placed on a planetary ball mill, and ball milled and mixed at a speed of 600 rpm for 1 hour, and the resulting mixed product is heated to 600 degrees Celsius at a heating rate of 10 degrees Celsius / minute under vacuum conditions, and kept for 12 hours Release hydrogen, vacuumize the system once every 0.5 hours during the heat preservation stage, and then cool down to room temperature to obtain Li-Si-O composites with different lithium contents. The obtained Li-Si-O composite was put into a ball mill jar with a ball-to-material ratio of 30:1, and then the ball mill jar was placed on a vibrating ball mill for 4 hours at a frequency of 1200 cycles / min to obtain a negative electrode material for a lithium-ion battery. figure 1 It is the X-ray diffraction spectrum of the obtained lithium ion batt...

Embodiment 4

[0035] In a glove box filled with argon, weigh LiH and SiO at a molar ratio of 1.2:1, put them into a ball mill jar with a ball-to-material ratio of 100:1, and place the ball mill jar containing the mixture on a horizontal planetary ball mill , ball milled at a speed of 200 rpm for 10 hours to obtain a mixture, and the resulting mixture was heated to 500 degrees Celsius at a heating rate of 5 degrees Celsius / minute under the protection of nitrogen flow, and kept for 36 hours to dehydrogenate, and the dehydrogenated product dropped to room temperature , get Li 1.2 -Si-O complex. The obtained product was put into a ball mill tank with a ball-to-material ratio of 60:1, placed on a planetary ball mill, and ball milled at a speed of 500 rpm for 8 hours to obtain the final product. The resulting final product was assembled into a simulated battery for electrochemical testing.

[0036] image 3 Shown is the first charge-discharge curve of the resulting final product. Depend on ...

Embodiment 5～8

[0038] In the glove box, weigh LiH and SiO into the ball milling jar according to the molar ratio of 0.1:1, 0.4:1, 0.75:1 and 1:1 respectively, and the ball-to-material ratio is 60:1. Placed on a vibrating ball mill, ball milled at a frequency of 1200 cycles / min for 2 hours, then heated the obtained mixture to 550 degrees Celsius at a heating rate of 12 degrees Celsius / minute under the protection of high-purity argon flow, and kept it warm for 24 hours to release hydrogen. The dehydrogenated product was cooled to room temperature, and finally the obtained dehydrogenated product was put into a ball mill tank with a ball-to-material ratio of 20:1, and ball milled on a horizontal planetary ball mill at a speed of 600 rpm for 36 hours to obtain the final product. The resulting final product was assembled into a simulated battery for electrochemical testing.

[0039] Figure 4 Shown is the cycle stability curve of the resulting final product. From Figure 4 It can be seen that the...

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PUM

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Abstract

The invention discloses a preparation method for a lithium-ion battery cathode material with a high initial coulomb efficiency. The preparation method comprises the following steps of: (1) mixing LiH with SiO to obtain a mixture; (2) heating the mixture to a predetermined temperature in a vacuum or an inert atmosphere, and performing heat-insulating hydrogen desorption to obtain a hydrogen desorption product; and (3) performing high-energy ball milling on the hydrogen desorption product to obtain the lithium-ion battery cathode material. According to the preparation method provided by the invention, a Li-Si-O compound is formed in the lithium-ion battery cathode material via partial chemical pre-embedment of lithium, so that the initial coulomb efficiency of the lithium-ion battery cathode material is increased to be greater than 90%; and the preparation method is simple, effective, economic and practical.

Description

technical field [0001] The invention relates to the field of SiO lithium-ion battery materials, in particular to a method for preparing a lithium-ion battery negative electrode material with high coulombic efficiency for the first time. Background technique [0002] With the continuous development of human society, the energy crisis and environmental problems are becoming more and more serious. Safe, efficient, and clean energy conversion, storage, and utilization technologies are the key to solving energy and environmental problems. Among them, lithium-ion battery technology is known for its high energy density, wide operating temperature range, strong charge retention, and long battery life. The characteristics of cycle life and good environmental friendliness have attracted widespread attention, and are widely used in smart home appliances, electric tools, mobile communications and other fields. [0003] However, the rapid development of portable devices and the wide app...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1391H01M4/485
CPCY02E60/10
Inventor 刘永锋马瑞军潘洪革高明霞
Owner ZHEJIANG UNIV
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