CN102403504A

CN102403504A - Method for preparing lithium ion battery cathode material LiMnPO4 through low-temperature solid-phase reaction

Info

Publication number: CN102403504A
Application number: CN2011104109211A
Authority: CN
Inventors: 钟胜奎; 徐悦斌; 姜吉琼; 王友; 张鹰鹛
Original assignee: Guilin University of Technology
Current assignee: Guilin University of Technology
Priority date: 2011-12-10
Filing date: 2011-12-10
Publication date: 2012-04-04

Abstract

The invention discloses a method for preparing a lithium ion battery cathode material LiMnPO4 through low-temperature solid-phase reaction. The method comprises the following steps of: uniformly mixing a manganese source compound, a phosphorus source compound and a lithium source compound in the molar ratio of manganese to phosphorus to lithium of 1:1:1 at normal temperature; mechanically activating for 1 to 10 hours; adding an organic carbon source, wherein the molar ratio of the organic carbon to the manganese source compound is (1:1)-(2:1); heating to 300 to 800 DEG C at the heating speed of 10 to 40 DEG C per minute in non-oxidizing atmosphere; sintering at the constant temperature for 4 to 12 hours; and reducing the temperature at the speed of 5 to 20 DEG C per minute to obtain LiMnPO4. In the invention, a mangano-compound is directly used as a manganese source, an organic carbon source is added, and LiMnPO4 with stable performance can be prepared at low temperature, so the synthesis condition and cost are reduced, the capacity of the LiMnPO4 prepared by the method is obviously improved, and the LiMnPO4 has good discharge performance.

Description

Low-temperature solid phase reaction prepares anode material for lithium-ion batteries LiMnPO 4Method

Technical field

The present invention relates to a kind of low-temperature solid phase reaction and prepare anode material for lithium-ion batteries LiMnPO ₄Method.

Background technology

LiMnPO ₄It is a kind of new type lithium ion battery positive electrode.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 electric automobile of power.

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

Summary of the invention

The objective of the invention is to overcome the weak point of said method, provide a kind of low-temperature solid phase reaction to prepare anode material for lithium-ion batteries LiMnPO ₄Method.The lithium manganese phosphate particle that adopts the method to synthesize is tiny and particle size distribution is even, and ionic conductivity and electron conduction are significantly improved, and have good discharge performance; This method synthesis temperature is low simultaneously, and synthesis cycle is short, and condition control is easy, and synthetic method is simple, is easy to realize extensive industrialization.

Concrete steps of the present invention are:

Is 1: 1: 1 mixed with manganese source compound, P source compound and Li source compound by the ratio of manganese, phosphorus, elemental lithium amount of substance, mixes at normal temperatures, carries out mechanical activation then; Soak time is controlled in the 1-10h; Add organic carbon source then, organic carbon source is 1 with the ratio of the amount of substance of manganese source compound: 1-2: 1, under normal temperature and pressure conditions; Programming rate with 10-40 ℃/min in non-oxidizing atmosphere is heated to 300-800 ℃, and calcining at constant temperature 4-12h; Speed cooling with 5-20 ℃/min promptly gets LiMnPO ₄

Said manganese source compound is a kind of in manganese carbonate, manganese acetate and the manganese nitrate.

Said P source compound is a kind of in ammonium di-hydrogen phosphate, DAP, phosphoric acid ammonia and the phosphoric acid.

Said Li source compound is a kind of in lithium carbonate, lithium formate, lithium hydroxide, lithium acetate and the lithia.

Said organic carbon source is a kind of in ascorbic acid, ethanedioic acid, adipic acid, malonic acid, mandelic acid, malic acid, lactic acid, citric acid, formaldehyde and the acetaldehyde.

Said non-oxidizing gas is a kind of in argon gas, helium, neon, nitrogen and the hydrogen.

Low Temperature Heat Treatment provided by the invention prepares anode material for lithium-ion batteries LiMnPO ₄Method compare with prior preparation method, its advantage is in particular in following aspect:

1) after the employing organic carbon source is handled raw material, synthetic LiMnPO ₄The sintering temperature of sample obviously reduces, and that is to say to have reduced the synthetic energy consumption of material, thereby has reduced synthetic cost.

2) LiMnPO for preparing in this way ₄Specific discharge capacity is respectively under the discharge-rate of normal temperature and pressure 0.05C: 158mAh.g ^-1, reach 92.9% of theoretical capacity.Material has height ratio capacity and good discharge performance.

Description of drawings

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

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

Fig. 3 is the charging and discharging curve figure of No. 3 samples in the embodiment of the invention 1.

Embodiment

Embodiment 1:

With MnCO ₃, LiCHO ₂, NH ₄H ₂PO ₄And C ₂H ₂O ₄.2H ₂O, by the ratio of amount of substance 1: 1: 1: 1 mixed, and mechanical activation 10h; Pack into then in the tube furnace, under argon gas atmosphere, temperature is respectively at 300 ℃, 500 ℃, 600 ℃, 700 ℃ constant temperature 12h.Wherein the stove heating rate is controlled at 20 ℃/min, and rate of temperature fall is controlled at 5 ℃/min.The material of gained is an olivine structural through X-ray diffraction analysis, and space group is Pnmb, is the structure of LiMnPO4.Resulting product is assembled into button cell surveys its charging and discharging capacity and cycle performance, under the 0.05C multiplying power, discharge and recharge, discharge capacity is seen table 1 after its discharge capacity and circulation first 30 times.

The experiment condition of table 1 embodiment 1 and result

Embodiment 2:

With Mn (NO ₃) ₂, LiOH, (NH ₄) ₂HPO ₄And HCHO, by the ratio of amount of substance 1: 1: 1: 1 mixed, and mechanical activation 5h; Pack into then in the tube furnace, under nitrogen atmosphere, temperature is respectively at 650 ℃ of constant temperature 2h, 5h, 8h, 10h.Wherein the stove heating rate is controlled at 40 ℃/min, and rate of temperature fall is controlled at 20 ℃/min.The material of gained is an olivine structural through X-ray diffraction analysis, and space group is Pnmb, is LiMnPO ₄Structure.Resulting product is assembled into button cell surveys its charging and discharging capacity and cycle performance, under the 0.05C multiplying power, discharge and recharge, discharge capacity is seen table 2 after its discharge capacity and circulation first 30 times.

The experiment condition of table 2 embodiment 2 and result

Claims

1. one kind prepares anode material for lithium-ion batteries LiMnPO ₄Method, it is characterized in that concrete steps are:

Is 1: 1: 1 mixed with manganese source compound, P source compound and Li source compound by the ratio of manganese, phosphorus, elemental lithium amount of substance, mixes at normal temperatures, carries out mechanical activation then; Soak time is controlled in the 1-10h; Add organic carbon source then, organic carbon source is 1 with the ratio of the amount of substance of manganese source compound: 1-2: 1, under normal temperature and pressure conditions; Programming rate with 10-40 ℃/min in non-oxidizing atmosphere is heated to 300-800 ℃, and calcining at constant temperature 4-12h; Speed cooling with 5-20 ℃/min makes LiMnPO ₄

Said manganese source compound is a kind of in manganese carbonate, manganese acetate and the manganese nitrate;

Said P source compound is a kind of in ammonium di-hydrogen phosphate, DAP, phosphoric acid ammonia and the phosphoric acid;

Said Li source compound is a kind of in lithium carbonate, lithium formate, lithium hydroxide, lithium acetate and the lithia;

Said organic carbon source is a kind of in ascorbic acid, ethanedioic acid, adipic acid, malonic acid, mandelic acid, malic acid, lactic acid, citric acid, formaldehyde and the acetaldehyde;