CN102969506A

CN102969506A - Modified lithium ferric manganese phosphate anode material and preparation method thereof

Info

Publication number: CN102969506A
Application number: CN2012105371333A
Authority: CN
Inventors: 姜应律; 陈蕾; 陈海涛; 杨国凯; 熊辉
Original assignee: HANGZHOU NANDU ENERGY TECHNOLOGY Co Ltd; HANGZHOU NARADA BATTERY CO Ltd; Zhejiang Narada Power Source Co Ltd
Current assignee: HANGZHOU NANDU ENERGY TECHNOLOGY Co Ltd; HANGZHOU NARADA BATTERY CO Ltd; Zhejiang Narada Power Source Co Ltd
Priority date: 2012-12-11
Filing date: 2012-12-11
Publication date: 2013-03-13

Abstract

The invention relates to a modified lithium ferric manganese phosphate anode material and a preparation method thereof. The anode material comprises a lithium source, a phosphorus source, an iron source, a manganese source, a stibium source and a carbon source. The preparation method comprises the following steps of: 1) placing the phosphorus source, the iron source, the manganese source and the stibium source in a reaction kettle and reacting while stirring at a speed of 800-1500 r/min; heating the mixture to a temperature of 60-100 DEG C and reacting for 5-18 hours; and drying and crushing the mixture after the reaction is finished; 2) pre-sintering: under the protection of nitrogen, heating to a temperature of 500-700 DEG C at the speed of 2-10 DEG C/min and keeping the temperature for 5-10 hours, and cooling with a furnace; 3) mixing: mixing a pre-sintered product with a certain amount of the lithium source, adding the carbon source, using absolute ethyl alcohol as a dispersing agent, carrying out ball milling by using a ball milling machine at a speed of 800-2000 r/min for 2-10 hours, and drying and crushing products after ball milling; and 4) carrying out high-temperature sintering: under the protection of the nitrogen, heating to a temperature of 600-900 DEG C at the speed of 2-10 DEG C/min and keeping the temperature for 5-20 hours, and cooling with the furnace so as to obtain the lithium ferric manganese phosphate anode material. The material prepared by the invention has the advantages of stable property and good consistency; and the primary discharge capacity of the product 0.1 C reaches 154.1 mAh/g, and the capacity of the obtained product after 50 times of circulation is 148.8 mAh/g.

Description

A kind of modified phosphate ferrimanganic lithium anode material and preparation method thereof

Technical field

The present invention relates to the lithium ion battery material technical field, especially relate to modification of a kind of lithium ion battery positive pole material phosphoric acid ferrimanganic lithium material and preparation method thereof.

Background technology

Lithium ion battery is compared the other types storage battery and is had that energy height, operating voltage are high, volume is little, has extended cycle life, the advantages such as self discharge is low, memory-less effect are widely used in electronics, the electric equipment.

Present commercial lithium ion battery mainly is LiCoO ₂But the cobalt price is high, toxic; environment and human body there is certain injury; along with the increase of people's environmental consciousness and businessman, the buyer pursuit to cost performance, need to find a kind of substitute, this wherein the LiFePO4 of olivine structural be the emphasis that people study all the time; because iron resource is abundant, avirulence, cost performance are high; be to be considered to promise to be the lithium ion anode material that scale drops into practical application most, and studies show that LiFePO ₄Exist conductivity lower, the high power charging-discharging capacity attenuation is very fast, the shortcomings such as voltage platform lower (3.3V), thus limited its practical application.

Summary of the invention

First purpose of the present invention is for the existing technical matters of LiFePO4, proposes a kind of modified phosphate ferrimanganic lithium anode material.The chemical composition of described modified phosphate ferrimanganic lithium anode material is Li _1-ySb _yFexMn _1-xPO ₄, wherein the scope of x is 0.2≤x≤0.8, the doping ion is antimony (Sb), 0.01≤y≤0.5.

The present invention replaces iron position in the LiFePO4 with a part of manganese element, when being conducive to its electrochemical reaction ion in the diffusion of crystals, the polarization when having reduced heavy-current discharge, and improved discharge voltage plateau.Ionic conductivity and electronic conductivity that the antimony dopant modification that the present invention adopts and carbon coated are improved material, the electric conductivity of raising material.Another purpose of the present invention provides a kind of preparation method of above-mentioned modified phosphate ferrimanganic lithium anode material.For this reason, the present invention by the following technical solutions, it comprises following preparation process:

1), presses the chemical composition Li of modified phosphate ferrimanganic lithium _1-ySb _yFexMn _1-xPO ₄Place reactor to carry out stirring reaction in phosphorus source, source of iron, manganese source, antimony source, and be heated to 60-100 ℃ of reaction 5-18h, reaction is dried pulverizing after finishing, wherein, and 0.2≤x≤0.8,0.01≤y≤0.5;

2) pre-burning: under the nitrogen protection atmosphere condition, be warming up to 500-700 ℃ and be incubated 5-10h with the speed of 2-10 ℃/min, cool off with stove;

3) batch mixing: in (1-y): 1 wherein the ratio of (0.01≤y≤0.5) the lithium source is mixed with the product source of pre-burning, and adding carbon source, as dispersant, with 800-2000r/min ball milling 2-10h, the ball milling afterproduct is dried and is pulverized in ball mill with absolute ethyl alcohol;

4) high temperature sintering: place tube furnace, under nitrogen protection atmosphere, be warming up to 600-900 ℃ and be incubated 5-20h with the speed of 2-10 ℃/min, with the stove cooling, obtain the lithium ferric manganese phosphate positive electrode.

On the basis of adopting above technical scheme, the present invention also can adopt following further technical scheme:

Described source of iron is one or more in ferrous oxalate, iron oxide, iron powder, ferric phosphate, the ferrous phosphate.

Described manganese source is one or more in electrolytic manganese dioxide, mangano-manganic oxide, the manganese powder.

Described phosphorus source is one or more in ammonium dihydrogen phosphate, phosphoric acid, the polyphosphoric acids.

Described lithium source is one or more in lithium carbonate, lithium hydroxide, the lithium acetate.

Described antimony source is one or more in antimonous oxide, the antimony powder.

Described carbon source is one or more in sucrose, glucose, citric acid, polypropylene, the polyethylene glycol.

Described product with pre-burning mixes with the lithium source, and adds carbon source, and the adding proportion of carbon source is the 1%-10% of pre-burning product, lithium source and carbon source gross mass.

Because adopt technical scheme of the present invention, the present invention has the following advantages than prior art:

1, the present invention adopts high temperature solid-state to synthesize Li _1-ySb _yFexMn _1-xPO ₄Positive electrode, product are olivine structural, complete in crystal formation;

2, the lithium ferric manganese phosphate that synthesizes of the present invention is with low cost, security performance good, product avirulence, discharge voltage plateau are higher;

3, coat the anode material for lithium-ion batteries of synthetic chemical property excellence by antimony doping and carbon, 0.1C first discharge capacity reaches 154.1mAh/g, and capacity is 148.8mAh/g after 50 circulations.

Description of drawings

Fig. 1 is the Li that the embodiment of the invention 1 makes _0.95Sb _0.05Fe _0.7Mn _0.3PO ₄Discharge and recharge-voltage curve;

Fig. 2 is the Li that the embodiment of the invention 1 makes _0.95Sb _0.05Fe _0.7Mn _0.3PO ₄The discharge cycles curve chart;

Fig. 3 is the Li that the embodiment of the invention 2 makes _0.98Sb _0.02Fe _0.6Mn _0.4PO ₄X-ray diffractogram;

Fig. 4 is the Li that the embodiment of the invention 3 makes _0.99Sb _0.01Fe _0.8Mn _0.2PO ₄Stereoscan photograph (10000 times).

Embodiment

Embodiment 1, with reference to accompanying drawing 1-2

Take by weighing iron powder 39.088g; electrolytic manganese dioxide 26.079g; antimonous oxide 7.3g, phosphatase 79 8g place reactor with stirring reaction under the rotating speed of 1000r/min, and are heated to 60 ℃ of reaction 12h; reaction is poured out reactor with it after finishing; put into the dry oven dry of baking oven, after grinding or pulverization process, put into tube furnace; under the nitrogen protection atmosphere condition; speed with 2 ℃/min is warming up to 500 ℃, and constant temperature pre-burning 5h cools off with stove; product and 35.09g lithium carbonate with pre-burning; 21g sucrose mixes; as dispersant, on ball mill, with 1500r/min ball milling 5h, put into crucible after the taking-up oven dry with absolute ethyl alcohol; then crucible is put into tube furnace; speed with 2 ℃/min is warming up to 700 ℃, and constant temperature sintering 12h cools off with stove; make the lithium ferric manganese phosphate positive electrode, chemical composition is Li _0.95Sb _0.05Fe _0.7Mn _0.3PO ₄Under 23 ℃ of conditions of constant temperature, 0.1C first discharge capacity is 154.1mAh/g, and obvious discharge platform is arranged, and sees accompanying drawing 1.0.1C the multiplying power cyclic curve as shown in Figure 2, circulates that capacity is 148.8mAh/g after 50 times, shows Li _0.95Sb _0.05Fe _0.7Mn _0.3PO ₄Has good charge-discharge performance.

Embodiment 2, with reference to accompanying drawing 3

Take by weighing brown iron oxide 47.904g; mangano-manganic oxide 30.508g; antimonous oxide 7.3g, phosphatase 79 8g place reactor with stirring reaction under the rotating speed of 800r/min, and are heated to 70 ℃ of reaction 10h; reaction is poured out reactor with it after finishing; put into the dry oven dry of baking oven, after grinding or pulverization process, put into tube furnace; under the nitrogen protection atmosphere condition; speed with 5 ℃/min is warming up to 600 ℃, and constant temperature pre-burning 5h cools off with stove; product and 41.12g lithium hydroxide with pre-burning; 24g glucose mixes; as dispersant, on ball mill, with 1500r/min ball milling 10h, put into crucible after the taking-up oven dry with absolute ethyl alcohol; then crucible is put into tube furnace; speed with 5 ℃/min is warming up to 800 ℃, and constant temperature sintering 10h cools off with stove; make the lithium ferric manganese phosphate positive electrode, chemical composition is Li _0.98Sb _0.02Fe _0.6Mn _0.4PO ₄The surface topography of sample as shown in Figure 3, Fig. 3 is that sample amplifies 10000 times SEM photo, as can be seen from Figure, sample is loose and porous structure, most of particle diameter has a small amount of agglomeration about 2 microns.

Embodiment 3, with reference to accompanying drawing 4

Take by weighing ferrous oxalate 143.92g; manganese powder 10.99g; antimony powder 1.22g, phosphatase 79 8g place reactor with stirring reaction under the rotating speed of 1000r/min, and are heated to 80 ℃ of reaction 10h; reaction is poured out reactor with it after finishing; put into the dry oven dry of baking oven, after grinding or pulverization process, put into tube furnace; under the nitrogen protection atmosphere condition; speed with 5 ℃/min is warming up to 700 ℃, and constant temperature pre-burning 4h cools off with stove; product and 41.12g lithium hydroxide with pre-burning; 24g sucrose mixes; as dispersant, on ball mill, with 1200r/min ball milling 8h, put into crucible after the taking-up oven dry with absolute ethyl alcohol; then crucible is put into tube furnace; speed with 5 ℃/min is warming up to 750 ℃, and constant temperature sintering 8h cools off with stove; make the lithium ferric manganese phosphate positive electrode, chemical composition is Li _0.99Sb _0.01Fe _0.8Mn _0.2PO ₄The X-ray diffraction of sample can be seen by Fig. 4 that as shown in Figure 4 the diffraction maximum of sample is more sharp-pointed, and do not have the appearance of impurity peaks among the figure, and show that sample is purer, do not contain dephasign, the addition of antimony is few, does not show the peak position that of antimony among the figure, has also shown the synthetic Li of the method simultaneously _0.99Sb _0.01Fe _0.8Mn _0.2PO ₄Feasible.

Claims

1. modified phosphate ferrimanganic lithium anode material, it is characterized in that: the chemical composition of described modified phosphate ferrimanganic lithium is Li _1-ySb _yFexMn _1-xPO ₄, wherein the scope of x is 0.2≤x≤0.8, the doping ion is antimony (Sb), 0.01≤y≤0.5.

2. the preparation method of a kind of modified phosphate ferrimanganic lithium anode material claimed in claim 1, it is characterized in that: it comprises following preparation process:

1), presses the chemical composition Li of modified phosphate ferrimanganic lithium _1-ySb _yFexMn _1-xPO ₄Place reactor carrying out stirring reaction under the speed of 800-1500r/min in phosphorus source, source of iron, manganese source, antimony source, and be heated to 60-100 ℃ of reaction 5-18h, reaction is dried pulverizing after finishing, wherein, and 0.2≤x≤0.8,0.01≤y≤0.5;

3) batch mixing: in (1-y): 1 ratio is mixed the lithium source with the product source of pre-burning, and adds carbon source, and as dispersant, with 800-2000r/min ball milling 2-10h, the ball milling afterproduct is dried and pulverized in ball mill with absolute ethyl alcohol;

3. preparation method according to claim 2 is characterized in that, described source of iron is one or more in ferrous oxalate, iron oxide, iron powder, ferric phosphate, the ferrous phosphate.

4. preparation method according to claim 2 is characterized in that, described manganese source is one or more in electrolytic manganese dioxide, mangano-manganic oxide, the manganese powder.

5. preparation method according to claim 2 is characterized in that, described phosphorus source is one or more in ammonium dihydrogen phosphate, phosphoric acid, the polyphosphoric acids.

6. preparation method according to claim 2 is characterized in that, described lithium source is one or more in lithium carbonate, lithium hydroxide, the lithium acetate.

7. preparation method according to claim 2 is characterized in that, described antimony source is one or more in antimonous oxide, the antimony powder.

8. preparation method according to claim 2 is characterized in that, described carbon source is one or more in sucrose, glucose, citric acid, polypropylene, the polyethylene glycol.

9. preparation method according to claim 2 is characterized in that, the product of pre-burning is mixed with the lithium source, and add carbon source, and the adding proportion of carbon source is the 1%-10% of pre-burning product, lithium source and carbon source gross mass.

10. preparation method according to claim 2 is characterized in that, the antimony source of adding is be used to the ionic conductivity that improves material and electronic conductivity, improves the electric conductivity of material.