Summary of the invention
Given this, embodiment of the present invention first aspect provides a kind of lithium ion battery compound negative material, easily reunites, easily reacts with electrolyte and decompose, thereby cause battery to have lower durability and the problem of cycle performance to solve sulfide negative material.Embodiment of the present invention second aspect provides the preparation method of the compound negative material of a kind of lithium ion battery.The embodiment of the present invention third aspect provides a kind of lithium ion battery.
First aspect, the embodiment of the present invention provides a kind of lithium ion battery compound negative material, comprises transient metal sulfide, and the coating layer that is arranged on described transient metal sulfide surface, and described transient metal sulfide is NiS, FeS
2, FeS, TiS
2, MoS and Co
9s
8in one or more, the material of described coating layer comprises lithium titanate Li
4ti
5o
12.
Compared with prior art, the compound negative material of lithium ion battery provided by the invention is by transient metal sulfide, and the coating layer that is arranged on transient metal sulfide surface forms, and wherein, transient metal sulfide is selected from NiS(nickel sulfide), FeS
2(ferrous disulfide), FeS(ferrous sulfide), TiS
2(titanium disulfide), MoS(molybdenum sulfide) and Co
9s
8one or more in (cobalt sulfide).The embedding lithium capacity of these transient metal sulfides is high, as NiS and FeS
2embedding lithium capacity be about 600mAh/g, thereby can make the compound negative material of lithium ion battery there is higher capacity.
The material of coating layer comprises lithium titanate Li
4ti
5o
12there is following several large advantage: (1) lithium titanate is " zero strain " electrode material, according to the people's such as S.Schamer result of study (J.of electrochemical society, 146 (3), 1999,857,861), the lithium titanate of cubic spinel structure is in lithium ion embedding-Tuo embedding process, and lattice parameter maximum is from 8.3595
narrow down to 8.3538
, lattice constant changes very little, and change in volume is very little, has kept the structural stability of height, therefore has excellent cycle performance; (2) lithium titanate has three-dimensional lithium ion passage, and its lithium ion diffusion coefficient, than the large order of magnitude of carbon-based negative electrode material, can improve the high rate performance of lithium battery; (3) the about 1.55V of the equilibrium potential of lithium titanate, can effectively avoid lithium metal deposition, improved the security performance of lithium ion battery, simultaneously because embedding lithium current potential is high, do not reach SEI film and form current potential, substantially there is not reduction decomposition in electrolyte, is conducive to maintain the stable of electrolyte on lithium titanate surface, improve cycle performance.But lithium titanate specific capacity is low, utilize the battery of its making, energy density is lower, and simultaneously lithium titanate material price is more expensive, and the commercialization of the battery that to have had a strong impact on lithium titanate be negative pole is used.
Therefore, the present invention is by lithium titanate Li
4ti
5o
12be coated on described transient metal sulfide surface; can the avtive spot of sulfide surface is coated; thereby effectively protect transient metal sulfide; prevent the decomposition that reacts of transient metal sulfide and electrolyte; stop sulfide to be reunited; when making the compound negative material of lithium ion battery there is high power capacity, possess good cyclical stability and durability.In addition, due to lithium titanate Li
4ti
5o
12have three-dimensional lithium ion passage, its lithium ion diffusion coefficient is large, thereby can improve the high rate performance of lithium ion battery.And the embedding lithium current potential of these transient metal sulfide materials and lithium titanate Li
4ti
5o
12approach, thereby can make the compound negative material of lithium ion battery there is steadily consistent charge and discharge platform.
Preferably, the thickness of described coating layer is 50 ~ 8000nm.More preferably, the thickness of described coating layer is 1000~4000nm.
Preferably, described transient metal sulfide accounts for 10% ~ 95% of the compound negative material gross mass of described lithium ion battery.
More preferably, described transient metal sulfide accounts for 60%~80% of the compound negative material gross mass of described lithium ion battery.
Due to lithium titanate Li
4ti
5o
12have lower electronic conductance and ionic conductance ability, therefore in order to improve the electric conductivity of the compound negative material of described lithium ion battery, the material of described coating layer can further comprise conductive additive.
Described conductive additive is one or more in Delanium, native graphite, acetylene black, carbon black, carbonaceous mesophase spherules, carbon nano-tube, carbon nano-fiber, phenolic resins, sucrose.Described conductive additive accounts for 1% ~ 5% of the compound negative material gross mass of described lithium ion battery.
The compound negative material of a kind of lithium ion battery that embodiment of the present invention first aspect provides, has high power capacity, and Stability Analysis of Structures, does not react with electrolyte, does not reunite, thereby finally can make lithium ion battery have higher durability and cyclical stability; In addition, due to lithium titanate Li
4ti
5o
12lithium ion diffusion coefficient is large, thereby can improve the high rate performance of lithium ion battery.
Second aspect, the embodiment of the present invention provides the preparation method of the compound negative material of a kind of above-mentioned lithium ion battery, comprises the following steps:
(1) coated raw material lithium source, titanium source and transient metal sulfide dispersed with stirring in decentralized medium to be covered is even, make slurry;
Described coated raw material lithium source is selected from one or more in lithium hydroxide, hydronium(ion) oxidation lithium, lithium carbonate, lithium nitrate, lithium sulfate, lithium fluoride, lithium oxalate, lithium chloride and lithium acetate;
Described coated raw material titanium source is selected from one or more in titanium dioxide, titanium tetrachloride, titanium trichloride, isopropyl titanate, butyl titanate, butyl titanate and metatitanic acid n-propyl;
Described transient metal sulfide is selected from NiS, FeS
2, FeS, TiS
2, MoS and Co
9s
8in one or more;
Described decentralized medium is selected from one or more in water, DMF (DMF), DMA (DMAc), N-2-methyl pyrrolidone (NMP), oxolane (THF), ethanol and methyl alcohol;
(2) the described slurry obtaining is coated and is made the compound negative material of lithium ion battery by sol-gel process, hydro-thermal reaction method, microwave chemical method or high temperature solid-state method; The compound negative material of described lithium ion battery comprises described transient metal sulfide, and the coating layer that is coated on described transient metal sulfide surface, and the material of described coating layer comprises lithium titanate Li
4ti
5o
12.
Preferably, the thickness of described coating layer is 50 ~ 8000nm.More preferably, the thickness of described coating layer is 1000~4000nm.
Preferably, described transient metal sulfide accounts for 10% ~ 95% of the compound negative material gross mass of described lithium ion battery.
More preferably, described transient metal sulfide accounts for 60%~80% of the compound negative material gross mass of described lithium ion battery.
The concrete operations of described sol-gel process are: described slurry is dry at 60 ~ 80 ℃, obtain persursor material, described persursor material is placed in to 500 ~ 700 ℃ of sintering of muffle furnace 1 ~ 5 hour, cools to room temperature with the furnace, obtain the compound negative material of lithium ion battery.
The concrete operations of described hydro-thermal reaction method are: described slurry is proceeded in hydrothermal reaction kettle, hydro-thermal ion-exchange reactions 8 ~ 12h at 150 ~ 160 ℃, obtain black precipitate, again black precipitate is placed in to the Muffle furnace heat treatment 1 ~ 3h of 500 ~ 600 ℃, cool to room temperature with the furnace, obtain the compound negative material of described lithium ion battery.
The concrete operations of described microwave chemical method are: described slurry is dry at 100 ~ 120 ℃, obtain persursor material, described persursor material is placed in to industrial microwave oven, with 10 ℃/min, be warmed up to 600 ~ 800 ℃, be incubated 1 ~ 4 hour, cooling with stove, obtain the compound negative material of described lithium ion battery.
The concrete operations of described high temperature solid-state method are: described slurry is dry at 100 ~ 120 ℃, obtain persursor material, described persursor material is placed in to Muffle furnace sintering 0.5 ~ 10 hour at 400 ~ 900 ℃, cooling with stove, obtain the compound negative material of described lithium ion battery.
Wherein, about transient metal sulfide and lithium titanate Li
4ti
5o
12concrete narration as mentioned before, repeat no more herein.
In order to improve the electric conductivity of the compound negative material of described lithium ion battery, described coated raw material can further comprise conductive additive, in step (1), add conductive additive, be dispersed in decentralized medium with lithium source, titanium source and transient metal sulfide to be covered, make slurry.
Described conductive additive is one or more in Delanium, native graphite, acetylene black, carbon black, carbonaceous mesophase spherules, carbon nano-tube, carbon nano-fiber, phenolic resins, sucrose.Described conductive additive accounts for 1% ~ 5% of the compound negative material gross mass of described lithium ion battery.
The preparation method of the compound negative material of a kind of lithium ion battery that embodiment of the present invention second aspect provides, simple, the compound negative material of lithium ion battery making has high power capacity, and Stability Analysis of Structures, do not react with electrolyte, do not reunite, lithium ion diffusion coefficient is large, thereby can make lithium ion battery there is higher durability and cyclical stability, can improve the high rate performance of lithium ion battery.
The third aspect, the embodiment of the present invention provides a kind of lithium ion battery, and this lithium ion battery comprises the compound negative material of lithium ion battery that embodiment of the present invention first aspect provides.
The cycle life of lithium ion battery that the embodiment of the present invention third aspect provides is long, and has good discharge capacity and high rate performance.
The advantage of the embodiment of the present invention will partly be illustrated in the following description, and a part is apparent according to specification, or can know by the enforcement of the embodiment of the present invention.
Embodiment
The following stated is the preferred implementation of the embodiment of the present invention; should be understood that; for those skilled in the art; do not departing under the prerequisite of embodiment of the present invention principle; can also make some improvements and modifications, these improvements and modifications are also considered as the protection range of the embodiment of the present invention.
Embodiment of the present invention first aspect provides a kind of lithium ion battery compound negative material, easily reunites, easily reacts with electrolyte and decompose, thereby cause battery to have lower durability and the problem of cycle performance to solve sulfide negative material.Embodiment of the present invention second aspect provides the preparation method of the compound negative material of a kind of lithium ion battery.The embodiment of the present invention third aspect provides a kind of lithium ion battery.
First aspect, the embodiment of the present invention provides a kind of lithium ion battery compound negative material, comprises transient metal sulfide, and the coating layer that is arranged on described transient metal sulfide surface, and described transient metal sulfide is NiS, FeS
2, FeS, TiS
2, MoS and Co
9s
8in one or more, the material of described coating layer comprises lithium titanate Li
4ti
5o
12.
Compared with prior art, the compound negative material of lithium ion battery provided by the invention is by transient metal sulfide, and the coating layer that is arranged on transient metal sulfide surface forms, and wherein, transient metal sulfide is selected from NiS(nickel sulfide), FeS
2(ferrous disulfide), FeS(ferrous sulfide), TiS
2(titanium disulfide), MoS(molybdenum sulfide) and Co
9s
8one or more in (cobalt sulfide).The embedding lithium capacity of these transient metal sulfides is high, as NiS and FeS
2embedding lithium capacity be about 600mAh/g, thereby can make the compound negative material of lithium ion battery there is higher capacity.
The material of coating layer comprises lithium titanate Li
4ti
5o
12there is following several large advantage: (1) lithium titanate is " zero strain " electrode material, according to the people's such as S.Schamer result of study (J.of electrochemical society, 146 (3), 1999,857,861), the lithium titanate of cubic spinel structure is in lithium ion embedding-Tuo embedding process, and lattice parameter maximum is from 8.3595
narrow down to 8.3538
, lattice constant changes very little, and change in volume is very little, has kept the structural stability of height, therefore has excellent cycle performance; (2) lithium titanate has three-dimensional lithium ion passage, and its lithium ion diffusion coefficient, than the large order of magnitude of carbon-based negative electrode material, can improve the high rate performance of lithium battery; (3) the about 1.55V of the equilibrium potential of lithium titanate, can effectively avoid lithium metal deposition, improved the security performance of lithium ion battery, simultaneously because embedding lithium current potential is high, do not reach SEI film and form current potential, substantially there is not reduction decomposition in electrolyte, is conducive to maintain the stable of electrolyte on lithium titanate surface, improve cycle performance.But lithium titanate specific capacity is low, utilize the battery of its making, energy density is lower, and simultaneously lithium titanate material price is more expensive, and the commercialization of the battery that to have had a strong impact on lithium titanate be negative pole is used.
Therefore, the present invention is by lithium titanate Li
4ti
5o
12be coated on described transient metal sulfide surface; can the avtive spot of sulfide surface is coated; thereby effectively protect transient metal sulfide; prevent the decomposition that reacts of transient metal sulfide and electrolyte; stop sulfide to be reunited; when making the compound negative material of lithium ion battery there is high power capacity, possess good cyclical stability and durability.In addition, due to lithium titanate Li
4ti
5o
12have three-dimensional lithium ion passage, its lithium ion diffusion coefficient is large, thereby can improve the high rate performance of lithium ion battery.And the embedding lithium current potential of these transient metal sulfide materials and lithium titanate Li
4ti
5o
12approach, thereby can make the compound negative material of lithium ion battery there is steadily consistent charge and discharge platform.
The embodiment of the present invention is not restriction of the position in the compound negative material of lithium ion battery to described transient metal sulfide, is coated in described coating layer; The embodiment of the present invention is not particularly limited the granular size of described transient metal sulfide, can be coated in described coating layer.
The thickness of described coating layer is 50 ~ 8000nm.In present embodiment, the thickness of described coating layer is 1000~4000nm.
Described transient metal sulfide accounts for 10% ~ 95% of the compound negative material gross mass of described lithium ion battery.
In present embodiment, described transient metal sulfide accounts for 60%~80% of the compound negative material gross mass of described lithium ion battery.
Described transient metal sulfide is selected from NiS(nickel sulfide), FeS
2(ferrous disulfide), FeS(ferrous sulfide), TiS
2(titanium disulfide), MoS(molybdenum sulfide) and Co
9s
8one or more in (cobalt sulfide).When transient metal sulfide is two or more, the ratio between different transient metal sulfides is not particularly limited.
Due to lithium titanate Li
4ti
5o
12have lower electronic conductance and ionic conductance ability, therefore in order to improve the electric conductivity of the compound negative material of described lithium ion battery, the material of described coating layer can further comprise conductive additive.
Described conductive additive is one or more in Delanium, native graphite, acetylene black, carbon black, carbonaceous mesophase spherules, carbon nano-tube, carbon nano-fiber, phenolic resins, sucrose.Described conductive additive accounts for 1% ~ 5% of the compound negative material gross mass of described lithium ion battery.
Described conductive additive is uniformly distributed in described coating layer, is positioned at lithium titanate Li
4ti
5o
12near material, conductive additive evenly mixes lithium titanate Li
4ti
5o
12in material, on described transient metal sulfide surface, form and mix coating layer.
The compound negative material of a kind of lithium ion battery that embodiment of the present invention first aspect provides, has high power capacity, and Stability Analysis of Structures, does not react with electrolyte, does not reunite, thereby finally can make lithium ion battery have higher durability and cyclical stability; In addition, due to lithium titanate Li
4ti
5o
12lithium ion diffusion coefficient is large, thereby can improve the high rate performance of lithium ion battery.
Second aspect, the embodiment of the present invention provides the preparation method of the compound negative material of a kind of above-mentioned lithium ion battery, comprises the following steps:
(1) coated raw material lithium source, titanium source and transient metal sulfide dispersed with stirring in decentralized medium to be covered is even, make slurry;
Described coated raw material lithium source is selected from one or more in lithium hydroxide, hydronium(ion) oxidation lithium, lithium carbonate, lithium nitrate, lithium sulfate, lithium fluoride, lithium oxalate, lithium chloride and lithium acetate;
Described coated raw material titanium source is selected from one or more in titanium dioxide, titanium tetrachloride, titanium trichloride, isopropyl titanate, butyl titanate, butyl titanate and metatitanic acid n-propyl;
Described transient metal sulfide is selected from NiS, FeS
2, FeS, TiS
2, MoS and Co
9s
8in one or more;
Described decentralized medium is selected from one or more in water, DMF (DMF), DMA (DMAc), N-2-methyl pyrrolidone (NMP), oxolane (THF), ethanol and methyl alcohol;
(2) the described slurry obtaining is coated and is made the compound negative material of lithium ion battery by sol-gel process, hydro-thermal reaction method, microwave chemical method or high temperature solid-state method; The compound negative material of described lithium ion battery comprises described transient metal sulfide, and the coating layer that is coated on described transient metal sulfide surface, and the material of described coating layer comprises lithium titanate Li
4ti
5o
12.
The embodiment of the present invention is not restriction of the position in the compound negative material of lithium ion battery to described transient metal sulfide, is coated in described coating layer; The embodiment of the present invention is not particularly limited the granular size of described transient metal sulfide, can be coated in described coating layer.
The thickness of described coating layer is 50 ~ 8000nm.In present embodiment, the thickness of described coating layer is 1000~4000nm.
Described transient metal sulfide accounts for 10% ~ 95% of the compound negative material gross mass of described lithium ion battery.
In present embodiment, described transient metal sulfide accounts for 60%~80% of the compound negative material gross mass of described lithium ion battery.
Described transient metal sulfide is selected from NiS(nickel sulfide), FeS
2(ferrous disulfide), FeS(ferrous sulfide), TiS
2(titanium disulfide), MoS(molybdenum sulfide) and Co
9s
8one or more in (cobalt sulfide).When transient metal sulfide is two or more, the ratio between different transient metal sulfides is not particularly limited.
Lithium titanate Li is pressed in He Tai source, described coated raw material lithium source
4ti
5o
12stoichiometric proportion add.
Described decentralized medium is selected from one or more in water, DMF (DMF), DMA (DMAc), N-2-methyl pyrrolidone (NMP), oxolane (THF), ethanol and methyl alcohol.When decentralized medium mixes use for two or more, the ratio between different dispersion is not particularly limited.
The concrete operations of described sol-gel process are: described slurry is dry at 60 ~ 80 ℃, obtain persursor material, described persursor material is placed in to 500 ~ 700 ℃ of sintering of muffle furnace 1 ~ 5 hour, cools to room temperature with the furnace, obtain the compound negative material of lithium ion battery.
The concrete operations of described hydro-thermal reaction method are: described slurry is proceeded in hydrothermal reaction kettle, hydro-thermal ion-exchange reactions 8 ~ 12h at 150 ~ 160 ℃, obtain black precipitate, again black precipitate is placed in to the Muffle furnace heat treatment 1 ~ 3h of 500 ~ 600 ℃, cool to room temperature with the furnace, obtain the compound negative material of described lithium ion battery.
The concrete operations of described microwave chemical method are: described slurry is dry at 100 ~ 120 ℃, obtain persursor material, described persursor material is placed in to industrial microwave oven, with 10 ℃/min, be warmed up to 600 ~ 800 ℃, be incubated 1 ~ 4 hour, cooling with stove, obtain the compound negative material of described lithium ion battery.
The concrete operations of described high temperature solid-state method are: described slurry is dry at 100 ~ 120 ℃, obtain persursor material, described persursor material is placed in to Muffle furnace sintering 0.5 ~ 10 hour at 400 ~ 900 ℃, cooling with stove, obtain the compound negative material of described lithium ion battery.
Wherein, about transient metal sulfide and lithium titanate Li
4ti
5o
12concrete narration as mentioned before, repeat no more herein.
In order to improve the electric conductivity of the compound negative material of described lithium ion battery, described coated raw material can further comprise conductive additive, in step (1), add conductive additive, be dispersed in decentralized medium with lithium source, titanium source and transient metal sulfide to be covered, make slurry.
Described conductive additive is one or more in Delanium, native graphite, acetylene black, carbon black, carbonaceous mesophase spherules, carbon nano-tube, carbon nano-fiber, phenolic resins, sucrose.Described conductive additive accounts for 1% ~ 5% of the compound negative material gross mass of described lithium ion battery.
Described conductive additive is uniformly distributed in described coating layer, is positioned at lithium titanate Li
4ti
5o
12near material, conductive additive evenly mixes lithium titanate Li
4ti
5o
12in material, on described transient metal sulfide surface, form and mix coating layer.
The preparation method of the compound negative material of a kind of lithium ion battery that embodiment of the present invention second aspect provides, simple, the compound negative material of lithium ion battery making has high power capacity, and Stability Analysis of Structures, do not react with electrolyte, do not reunite, lithium ion diffusion coefficient is large, thereby can make lithium ion battery there is higher durability and cyclical stability, can improve the high rate performance of lithium ion battery.
The third aspect, the embodiment of the present invention provides a kind of lithium ion battery, and this lithium ion battery comprises the compound negative material of lithium ion battery that embodiment of the present invention first aspect provides.
The cycle life of lithium ion battery that the embodiment of the present invention third aspect provides is long, and has good discharge capacity and high rate performance.
Divide a plurality of embodiment to be further detailed the embodiment of the present invention below.Wherein, the embodiment of the present invention is not limited to following specific embodiment.In the scope of constant principal right, carrying out change that can be suitable is implemented.
Embodiment mono-
The preparation method of the compound negative material of a kind of lithium ion battery
(1) take hydronium(ion) oxidation lithium (LiOHH
2o) 8.4g, titanium dioxide 20g are scattered in the deionized water of 150mL, add 2.3g acetylene black to be uniformly dispersed; Add again the abundant dispersed with stirring of 89.7g nickel sulfide even, obtain thick shape slurry;
(2) obtain persursor material by slurry is dry in 110 ℃ of drying ovens, persursor material is placed in industrial microwave oven, with the speed of 10 ℃/min, be warmed up to 700 ℃, be incubated 1 hour, cool to room temperature with the furnace, obtain lithium titanate Li
4ti
5o
12the compound negative material of lithium ion battery of coated nickel sulfide (NiS).
The preparation method of lithium ion battery
By the compound negative material of the present embodiment gained lithium ion battery, conductive black, binding agent Kynoar PVDF, 92:4:4 mixes in N-2-methyl pyrrolidone (NMP) in mass ratio, obtain mixed slurry, mixed slurry is applied on the aluminium foil of 16um, after dry, be cut into pole piece, take lithium sheet as to electrode, be assembled into CR2032 type button cell.Packaged battery carries out in the glove box of argon gas atmosphere, and electrolyte adopts 1mol/L LiPF
6eC:DMC(volume ratio be 1:1) mixed liquor, barrier film adopts Celgard2400.
Embodiment bis-
The preparation method of the compound negative material of a kind of lithium ion battery
(1) 13g lithium carbonate is dispersed to 500mL water and ethanol solution (wherein the volume ratio of water and ethanol is 4:1), the mol ratio that is 5:4 according to Ti:Li measures butyl titanate 75mL, with after the dilution of 80mL absolute ethyl alcohol, be added in the ethanol water that is dispersed with lithium carbonate, after stirring, add again the abundant dispersed with stirring of 176g ferrous disulfide even, obtain mixed slurry;
(2) slurry is dried and obtains persursor material in 110 ℃ of drying ovens, be placed in 600 ℃ of muffle furnaces and burn 4 hours, cool to room temperature with the furnace, obtain lithium titanate Li
4ti
5o
12coated ferrous disulfide (FeS
2) the compound negative material of lithium ion battery.
The preparation method of lithium ion battery
With embodiment mono-.
Embodiment tri-
The preparation method of the compound negative material of a kind of lithium ion battery
(1) take lithium nitrate 15.5g, titanium dioxide 20g is scattered in the deionized water of 200mL, adds carbon black 1.2g to be uniformly dispersed, then adds nickel sulfide 18.2g, the abundant dispersed with stirring of ferrous disulfide 18.2g evenly to obtain thick shape slurry;
(2) obtain persursor material by slurry is dry in 110 ℃ of drying ovens, persursor material is placed in industrial microwave oven, with the speed of 10 ℃/min, be warmed up to 650 ℃, be incubated 2 hours, cool to room temperature with the furnace, obtain lithium titanate Li
4ti
5o
12coated nickel sulfide (NiS) and ferrous disulfide (FeS
2) the compound negative material of lithium ion battery.
The preparation method of lithium ion battery
With embodiment mono-.
Embodiment tetra-
The preparation method of the compound negative material of a kind of lithium ion battery
(1) 20g lithium acetate is dispersed to ethanol solution, the mol ratio that is 5:4 according to Ti:Li measures isopropyl titanate 107g, with after the dilution of 200mL absolute ethyl alcohol, be added in the ethanol water that is dispersed with lithium acetate, after stirring, add again 6.8g carbon nano-tube, add again 120g MoS(molybdenum sulfide) fully dispersed with stirring is even, obtains gel-sol slurry;
(2) gel-sol slurry is dried and obtains persursor material in 60 ℃ of drying ovens, be placed in 650 ℃ of muffle furnaces and burn 2 hours, cool to room temperature with the furnace, obtain lithium titanate Li
4ti
5o
12coated MoS(molybdenum sulfide) the compound negative material of lithium ion battery.
The preparation method of lithium ion battery
With embodiment mono-.
Embodiment five
The preparation method of the compound negative material of a kind of lithium ion battery
(1) take hydronium(ion) oxidation lithium (LiOHH
2o) 8.4g, titanium dioxide 20g are scattered in the deionized water of 250mL, are uniformly dispersed; Add again 85.6g Co
9s
8(cobalt sulfide) fully dispersed with stirring is even, obtains mixing material;
(2) subsequently solution is proceeded in hydrothermal reaction kettle, add 4.5g conductive acetylene black at 160 ℃ hydro-thermal ion-exchange reactions 10h, obtain black precipitate, then black precipitate be placed in to the Muffle furnace heat treatment 2h of 500 ℃, cool to room temperature with the furnace, obtain lithium titanate Li
4ti
5o
12coated Co
9s
8the compound negative material of lithium ion battery of (cobalt sulfide).
The preparation method of lithium ion battery
With embodiment mono-.
Embodiment six
The preparation method of the compound negative material of a kind of lithium ion battery
(1) take hydronium(ion) oxidation lithium (LiOHH
2o) 16.8g, titanium dioxide 40g are scattered in the deionized water of 150mL; Add 2.5g Delanium, then add the abundant dispersed with stirring of 5.5g nickel sulfide even, obtain mixed slurry;
(2) obtain persursor material by slurry is dry in 110 ℃ of drying ovens, persursor material is placed in industrial microwave oven, with the speed of 10 ℃/min, be warmed up to 700 ℃, be incubated 1 hour, cool to room temperature with the furnace, obtain lithium titanate Li
4ti
5o
12the compound negative material of lithium ion battery of coated nickel sulfide (NiS).
The preparation method of lithium ion battery
With embodiment mono-.
Embodiment seven
The preparation method of the compound negative material of a kind of lithium ion battery
(1) take lithium nitrate 15.5g, titanium dioxide 20g is scattered in the deionized water of 500mL, then adds the abundant dispersed with stirring of ferrous disulfide 410.5g evenly to obtain thick shape slurry;
(2) obtain persursor material by slurry is dry in 110 ℃ of drying ovens, persursor material is placed in industrial microwave oven, with the speed of 10 ℃/min, be warmed up to 650 ℃, be incubated 2 hours, cool to room temperature with the furnace, obtain lithium titanate Li
4ti
5o
12coated ferrous disulfide (FeS
2) the compound negative material of lithium ion battery.
The preparation method of lithium ion battery
With embodiment mono-.
Comparative example one
To not be coated lithium titanate Li
4ti
5o
12nickel sulfide (NiS) be assembled into lithium ion battery, method is with embodiment mono-.
Comparative example two
To not be coated lithium titanate Li
4ti
5o
12ferrous disulfide (FeS
2) being assembled into lithium ion battery, method is with embodiment mono-.
Comparative example three
To not be coated lithium titanate Li
4ti
5o
12nickel sulfide (NiS) and ferrous disulfide (FeS
2) mix negative material and be assembled into lithium ion battery, method is with embodiment mono-.
Comparative example four
To not be coated lithium titanate Li
4ti
5o
12moS(molybdenum sulfide) be assembled into lithium ion battery, method is with embodiment mono-
Comparative example five
To not be coated lithium titanate Li
4ti
5o
12co
9s
8(cobalt sulfide) is assembled into lithium ion battery, and method is with embodiment mono-
The lithium ion battery making in above embodiment and comparative example is experimental cell, for following effect embodiment performance test.
Effect embodiment
For the beneficial effect that embodiment of the present invention technical scheme is brought provides powerful support for, spy provides following performance test:
By the lithium ion battery making in above-described embodiment and comparative example, adopt battery performance test instrument to carry out the test of charge and discharge cycles.Test condition is: charging is by voltage to 2.5V, and electric discharge is by voltage to 1.3V, and current density is 0.07mA/cm
2.
Fig. 1 is the cycle performance comparison diagram of the embodiment of the present invention one and comparative example one gained lithium ion battery.As can be seen from Figure 1, the embodiment mono-coated lithium titanate Li in surface
4ti
5o
12the specific capacity first of the compound negative material of nickel sulfide (NiS) lithium ion battery be 423mAh/g, the specific capacity first of nickel sulfide (NiS) material that comparative example one is not coated is 500mAh/g, but it is after 50 circulations, its specific capacity drops to 197mAh/g, only has 39.4% of specific capacity first; And the coated lithium titanate Li in surface
4ti
5o
12the compound negative material of nickel sulfide (NiS) lithium ion battery, through 50 times circulation after, its specific capacity drops to 399mAh/g, be first specific capacity 93%; Presentation of results: the coated lithium titanate Li in surface
4ti
5o
12nickel sulfide material, its cycle performance has obtained remarkable improvement.
Fig. 2 is the cycle performance comparison diagram of the embodiment of the present invention two and comparative example two gained lithium ion batteries.As can be seen from Figure 2, the embodiment bis-coated lithium titanate Li in surface
4ti
5o
12the specific capacity first of the compound negative material of ferrous disulfide lithium ion battery be 556mAh/g, the specific capacity first of the ferrous disulfide material that comparative example two is not coated is 600mAh/g, but it is after 50 circulations, and its specific capacity drops to 125mAh/g, only has 21% of specific capacity first; And the coated lithium titanate Li in surface
4ti
5o
12the compound negative material of ferrous disulfide lithium ion battery, through 50 times circulation after, its specific capacity drops to 512mAh/g, be first specific capacity 92%; Presentation of results: the coated lithium titanate Li in surface
4ti
5o
12ferrous disulfide material, its cycle performance has obtained remarkable improvement.
Fig. 3 is the cycle performance comparison diagram of the embodiment of the present invention three and comparative example three gained lithium ion batteries.As can be seen from Figure 3, the embodiment tri-coated lithium titanate Li in surface
4ti
5o
12nickel sulfide and the specific capacity first of the compound negative material of ferrous disulfide lithium ion battery be 394mAh/g, the specific capacity first of the nickel sulfide that comparative example three is not coated and ferrous disulfide composite material is 500mAh/g, but it is after 50 circulations, its specific capacity drops to 165mAh/g, only has 30% of specific capacity first; And the coated lithium titanate Li in surface
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12nickel sulfide and the compound negative material of ferrous disulfide lithium ion battery through 50 times circulation after, its specific capacity drops to 370mAh/g, be first specific capacity 94%; Presentation of results: the coated lithium titanate Li in surface
4ti
5o
12nickel sulfide and ferrous disulfide material, its cycle performance has obtained remarkable improvement.
Fig. 4 is the cycle performance comparison diagram of the embodiment of the present invention four and comparative example four gained lithium ion batteries.As can be seen from Figure 4, the embodiment tetra-coated lithium titanate Li in surface
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12the specific capacity first of the compound negative material of molybdenum sulfide lithium ion battery be 324.2mAh/g, the specific capacity first of the molybdenum sulfide that comparative example four is not coated is 400mAh/g, but it is after 50 circulations, and its specific capacity drops to 145.6mAh/g, only has 36.4% of specific capacity first; And the coated lithium titanate Li in surface
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12the compound negative material of molybdenum sulfide lithium ion battery through 50 times circulation after, its specific capacity drops to 298.5mAh/g, be first specific capacity 92.1%; Presentation of results: the coated lithium titanate Li in surface
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12material molybdenum sulfide, its cycle performance has obtained remarkable improvement.
Fig. 5 is the cycle performance comparison diagram of the embodiment of the present invention five and comparative example five gained lithium ion batteries.As can be seen from Figure 4, the embodiment tetra-coated lithium titanate Li in surface
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12the specific capacity first of the compound negative material of cobalt sulfide lithium ion battery be 298mAh/g, the specific capacity first of the molybdenum sulfide that comparative example four is not coated is 350mAh/g, but it is after 50 circulations, and its specific capacity drops to 73mAh/g, only has 20.8% of specific capacity first; And the coated lithium titanate Li in surface
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5o
12the compound negative material of cobalt sulfide lithium ion battery through 50 times circulation after, its specific capacity drops to 273mAh/g, be first specific capacity 91.6%; Presentation of results: the coated lithium titanate Li in surface
4ti
5o
12cobalt sulfide material, its cycle performance has obtained remarkable improvement.