CN102530908A

CN102530908A - Method for preparing silicon doping phosphate manganese lithium lithium-ion battery positive electrode material by sol-gel method

Info

Publication number: CN102530908A
Application number: CN2011104109014A
Authority: CN
Inventors: 钟胜奎; 张鹰鹛; 姜吉琼; 李伟
Original assignee: Guilin University of Technology
Current assignee: Guilin University of Technology
Priority date: 2011-12-10
Filing date: 2011-12-10
Publication date: 2012-07-04

Abstract

The invention discloses a method for preparing a silicon doping phosphate manganese lithium lithium-ion battery positive electrode material by a sol-gel method. The method of the invention comprises the steps of: uniformly mixing lithium salt, manganese salt, phosphoric acid salt and silane coupling agent by the mole ratio of 1: 1: 1: 0.2-0.5, sintering under the protection of inert gas at the temperature of 50-80 DEG C for 10-30 hours, and cooling to obtain LiMnPo4.The lithium salt is any one of lithium acetate, lithium nitrate and lithium fluoride; the manganese salt is any one of manganese carbonate, manganese acetate and manganous nitrate; the phosphoric acid salt is any one of ammonium dihydrogen phosphate, diammonium hydrogen phosphate and ammonium phosphate; the silane coupling agent is any one of ethenyl triethoxy silane, ethenyl trimethoxy silane and aniline methyl triethoxy silane; and the inert gas is either nitrogen or argon. According to the method of the invention, the sintering temperature is low, the method is simple and convenient and is easy to control, in addition, the charge and discharge performances and the cycling performance of LiMnPo4 are improved, and the cost is lowered.

Description

Sol-gel method prepares the lithium manganese phosphate anode material for lithium-ion batteries of silicon doping

Technical field

The present invention relates to the lithium manganese phosphate anode material for lithium-ion batteries that a kind of sol-gel method prepares silicon doping.

Background technology

LiMnPO ₄It is a kind of new type lithium ion battery positive electrode material.It has good charge and discharge platform, excellent cycle performance, and cheap, and theoretical capacity is high, and advantages of environment protection is considered to the most promising anode material for lithium-ion batteries, and to be expected to be used in the lithium ion battery be on the electromobile of power.

Traditional preparation method mainly contains following several kinds: solid-phase synthesis, coprecipitation method, hydrothermal method or the like.Yet all there are some inherent shortcomings in these methods, as: synthesis temperature is high, synthesis cycle is long, control condition is harsh, cost is high and the shortcomings such as large current discharging capability difference of synthetic materials, and these are all limiting LiMnPO ₄Extensive industrialization.

Summary of the invention

The object of the present invention is to provide a kind of lithium manganese phosphate anode material for lithium-ion batteries that adopts sol-gel process to prepare silicon doping.Sample size distribution after problem, the silicon dopings simultaneously such as lithium manganese phosphate material fade performance is fast is even, tiny, specific conductivity improves, reduce sintering temperature to solve; Reduce cost; Improve the chemical property of sample, simplified technology, made it to be easy to industrialized purpose.

Concrete steps are:

With lithium salts, manganese salt, phosphoric acid salt and silane coupling agent is 1: 1: 1 in molar ratio: after 0.2-0.5 mixes, under the protection of rare gas element, in 500 ℃ of-800 ℃ of sintering 10-30h, be LiMnPO after the cooling ₄

Said lithium salts is a kind of in Lithium Acetate, lithium nitrate and the lithium fluoride.

Said manganese salt is a kind of in manganous carbonate, manganous acetate and the manganous nitrate.

Said phosphoric acid salt is a kind of in primary ammonium phosphate, Secondary ammonium phosphate and the ammonium phosphate.

Said silane coupling agent is a kind of in vinyltriethoxysilane, vinyltrimethoxy silane and the anilinomethyl triethoxysilane.

Described rare gas element is a kind of in nitrogen and the argon gas.

Sintering temperature of the present invention is low, suppresses too growing up of sample crystal grain effectively, makes that institute's synthetic materials size distribution is even, tiny, has improved LiMnPO after the silicon doping ₄Specific conductivity; Adjustable between synthesis temperature 500-800 ℃, can obtain varigrained material; Method is simple and convenient, be easy to control; LiMnPO ₄Charge-discharge performance and cycle performance improve, reduced cost.

Description of drawings

Fig. 1 is the XRD figure of No. 3 samples of the embodiment of the invention 1.

Fig. 2 is the SEM figure of No. 3 samples of the embodiment of the invention 1.

Fig. 3 is the first charge-discharge curve of No. 3 samples of the embodiment of the invention 1.

Embodiment

Embodiment 1:

With 0.1mol Lithium Acetate, 0.1mol manganous carbonate and 0.1mol Secondary ammonium phosphate water-soluble after; Join mix in the 0.02mol vinyltriethoxysilane after; Under protection of nitrogen gas,, be LiMnPO after the cooling respectively at 500 ℃, 600 ℃, 700 ℃, 800 ℃ sintering 10h ₄Resulting product shows to be LiMnPO through X-ray diffraction analysis ₄, not having any dephasign, the particle diameter that can obtain product through SEM is about 0.1 μ m.Resulting product is assembled into the experiment button cell surveys its charging and discharging capacity and cycle performance, under the multiplying power of 1C, discharge and recharge, loading capacity is seen table 1 after its loading capacity and circulation first 50 times.

The experiment condition of table 1 embodiment 1 and result

Embodiment 2:

With 0.1mol lithium nitrate, 0.1mol manganous acetate and 0.1mol primary ammonium phosphate water-soluble after; Join mix in the 0.03mol vinyltrimethoxy silane after; Under the protection of argon gas,, be LiMnPO after the cooling in 700 ℃ of difference sintering 10,15,20 and 30h ₄Resulting product shows to be LiMnPO through X-ray diffraction analysis ₄, not having any dephasign, the particle diameter that can obtain product through SEM is about 0.1 μ m.Resulting product is assembled into the experiment button cell surveys its charging and discharging capacity and cycle performance, under the multiplying power of 1C, discharge and recharge, loading capacity is seen table 2 after its loading capacity and circulation first 50 times.

The experiment condition of table 2 embodiment 2 and result

Claims

1. method for preparing the lithium manganese phosphate anode material for lithium-ion batteries of silicon doping is characterized in that concrete steps are:

Said lithium salts is a kind of in Lithium Acetate, lithium nitrate and the lithium fluoride;

Said manganese salt is a kind of in manganous carbonate, manganous acetate and the manganous nitrate;

Said phosphoric acid salt is a kind of in primary ammonium phosphate, Secondary ammonium phosphate and the ammonium phosphate;

Said silane coupling agent is a kind of in vinyltriethoxysilane, vinyltrimethoxy silane and the anilinomethyl triethoxysilane;

Described rare gas element is a kind of in nitrogen and the argon gas.