CN100353595C

CN100353595C - Preparation method of high capacity tin antimony nickel alloy complex lithium ion battery cathode material

Info

Publication number: CN100353595C
Application number: CNB2005101306180A
Authority: CN
Inventors: 郭洪; 赵海雷; 仇卫华; 尹朝丽
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2005-12-15
Filing date: 2005-12-15
Publication date: 2007-12-05
Anticipated expiration: 2025-12-15
Also published as: CN1786221A

Abstract

The present invention provides a method for preparing an SnSbNi alloy composite negative electrode material for lithium ion batteries by a carbon thermal reduction method, which belongs to the technical field of the lithium ion batteries. The present invention is characterized in that tin, nickel and antimony oxides are prepared in the proportions as those of the Sn, the Sb and the Ni elements in the synthetic alloy composite, and carbon powders in appropriate proportion are then introduced as reducing agents; further, after being mixed and ground to be uniform, the obtained mixture is positioned in the gas atmosphere of a flowing inert argon gas while the temperature is raised to 800 DEG C and 1100 DEG C at a temperature raising rate of 5 to 30 DEG C /minute, and moreover, the temperature is kept constant for 1 to 3 hours; then, a power supply is switched off, and the mixture is cooled by means of furnace cooling to room temperature. The method of the present invention has the advantages of low cost and simple preparation technology and process, the synthetic SnSbNi alloy composite powders have the advantages of uniform and fine particle size and favorable degree of crystallization, and moreover, the prepared SnSbNi negative electrode material for the lithium ion battery has the advantages of high specific capacity and stable cycle performance. In addition, the highest reversible capacity can reach up to 379 mah/g, and the specific capacity can still remain about 90 % after 10 cycles.

Description

A kind of preparation method of high capacity tin antimony nickel alloy complex lithium ion battery cathode material

Technical field

The invention belongs to the lithium ion battery field, be specifically related to a kind of good SnSbNi alloy composite materials preparation method of specific capacity height, cycle performance who can be used as lithium ion battery negative material.A kind of method that adopts carbothermic method by preparation of metal oxides SnSbNi alloy powder material particularly is provided.

Background technology

Lithium ion battery is the latest generation rechargeable battery that has grown up behind the MH-Ni battery since the nineties, and it has the operating voltage height, energy density is big, fail safe good, light weight, self discharge are little, have extended cycle life, memory-less effect, advantage such as pollution-free.Be widely used in fields such as mobile phone, notebook computer, palmtop PC and military extraordinary electronic equipment at present, annual production, the output value increase very fast, become an emphasis of modern new energy development.

Present business-like lithium ion battery negative material adopts carbon class material mostly, but the lithium storage content that studies show that it is lower, its actual specific capacity is at present very near its theoretical specific capacity (the theory storage lithium amount as graphite is 372mAh/g), the space of further improving its specific capacity is very limited, especially is difficult to improve the material with carbon element volume and capacity ratio.In addition, material with carbon element is when the embedding lithium, and its electrode potential and lithium metal are close, and when battery overcharge, the easy precipitating metal lithium of carbon electrodes forms dendrite and causes short circuit, has a strong impact on the fail safe of battery.Therefore, exploitation specific capacity height, fail safe lithium ion battery negative material good, that cycle performance is good become present material worker and electrochemist's research focus.

Many metals and semimetal (as: Al, Mg, Ga, In, Sn, Zn, Cd, Si, Ge, Pb, Sb, Bi, Ni, Au, Ag, Pt etc.) can form alloy with lithium, and their storage lithium amount is considerable, and wherein the theoretical specific capacity of metallic tin is 990mAh/g, far above the graphite-like negative material.When but Li and single metal form alloy LixM, can be attended by very big volumetric expansion (2-3 doubly), this will cause electrode cycle performance variation, thereby hinder the practical application of alloy anode.Be the change in volume that suppresses or mitigation is followed in the removal lithium embedded process, usually take off the electrode matrix of embedding as Li with binary or multicomponent alloy, the research of activity/inactive metal alloy material becomes the focus of lithium ion battery negative material research in recent years, as Sn/SnSbx, Sn/SnAgx, Sn/SnFe, Sn/SnNi, nanometer-Si/C and nanometer-SnSb.Wherein one of metal mostly be that quality is softer, ductility inert matter preferably, variation to volume has stronger adaptability, when Li takes off embedding, can cushion the mechanical stress of bringing owing to the active material change in volume, thereby make alloy material have good cyclical stability, promptly prepare alloy or intermetallic compound base negative material.In order to cushion the bigger change in volume that the Sn sill is produced in the removal lithium embedded process, Besenhard research group is compound with Sn and Sb, because Sb also can and have higher capacity (Li with Li chemical combination ₃Sb, 660mAh/g), thereby the SnSb composite material demonstrates higher electrochemistry capacitance.Simultaneously, Sn is different with the removal lithium embedded current potential of Sb, thereby in the removal lithium embedded process, the change in volume that unreacted mutually can the buffering reaction phase be produced, thereby guaranteed that the SbSb composite material has good cyclical stability (M.Winter and J.O.Besenhard, Electrochimica Acta, 1999,45:31-50).Though metal Ni is not had an activity, the skeleton of toughness can be provided to alloy, can the efficient buffer electrochemical process in the mechanical swelling of system.Employing machine-alloyings such as the Shi Pengfei of Harbin Institute of Technology are prepared the SnNi alloy material of cathode, and initial capacity is 200mAh/g, circulate and decay to 50 mAh/g following (Shu Jie, Cheng Xinqun, Shi Pengfei, battery, 2004,34, (4): 235-237) after 5 times.The Z.F.Ma of Shanghai Communications University etc. adopt liquid phase reduction, prepare the SnNi/CMS negative material, and initial capacity is 360mAh/g, circulating, capacity is 300mAh/g (X.Liao, Z.F.Ma, X.Yuan after 10 times, Electrochemistry Communications, 2003,5:657-661).

The method that alloy material of cathode adopts chemical liquid phase reduction, high-energy ball milling, electro-deposition or chemical heat to decompose more is prepared, complicated process of preparation, and length consuming time, the cost height, productive rate is low.Thereby it is low to research and develop a kind of cost, is convenient to large-scale production, and the multicomponent alloy negative material of while electrochemical specific capacity height, good cycling stability is for promoting the practical application of alloy material in lithium ion battery to have great importance.

Summary of the invention

The objective of the invention is to: the preparation method that a kind of lithium ion battery SnSbNi ternary combination electrode material is provided, adopt carbothermic method, not only cost is low, preparation process is simple, and the uniform particles of synthetic SnSbNi alloy powder is tiny, degree of crystallinity is good, SnSbNi lithium ion battery negative material specific capacity height, the good cycling stability prepared.

The present invention's employing carbothermic method utilizes carbon dust as reducing agent, the oxide of reduction tin, antimony and nickel, the alloy complex negative material of preparation different proportion; The concrete technology of the synthetic SnSbNi alloy material of cathode of carbon thermal reduction technology is:

Tin oxide, antimony oxide, nickel oxide and activated carbon or the carbon black powder of 100nm-100 μ m are carried out the weighing proportioning: the addition of tin oxide and nickel oxide presses Sn and the Sb atomic ratio calculated in 3: 1～1: 3, the addition of nickel oxide accounts for 10～60% (atomic percents of total alloy amount by Ni, with respect to Sn+Sb+Ni), the addition of activated carbon or carbon black all is reduced to CO by the oxygen in the oxide raw material and calculates, shown in chemical formula (1) (with SnO ₂, Sb ₂O ₃, Ni ₂O ₃During for raw material), x: 2y=3 wherein: 1～1: 3,2z: (x+2y+2z)=0.1～0.6.The consumption of C can excessive 5～30 atom %, as reduction protection.

xSnO ₂+ySb ₂O ₃+zNi ₂O ₃+(2x+3y+3z)C＝Sn _xSb _2yNi _2z+(2x+3y+3z)CO (1)

Adopt mechanical dry method mixed or wet mixing that raw material is mixed; Mixture places the heating furnace that is connected with flowing nitrogen or argon gas atmosphere, reaches temperature required 800～1100 ℃ with 5～30 ℃/minute heating rates, is incubated 2～6 hours; Outage cools to room temperature naturally with the furnace then.Control the ratio of tin oxide, antimony oxide and nickel oxide in the initiation material, can effectively control the ratio of three kinds of elements in the gained SnSbNi product.

According to calculation of thermodynamics, the oxide of tin, antimony and nickel (450～650 ℃) under relatively low temperature can be reduced to metal Sn, Sb, Ni by C.The fusing point of Sn, Sb is lower: be respectively 232 ℃ and 631 ℃, the metal Sn that restores, Sb have higher activity, and easy and Ni alloying generates SnSbNi alloy or the intermetallic compound with stabilization of bony shelf structure.Simultaneously, Sn and Sb all can close with lithiumation, and show higher lithium storage content, and the removal lithium embedded current potential difference of the two, volumetric expansion and the mechanical stress, particularly Ni that unreacted mutually can the buffering reaction phase be produced in the process of SnSbNi and lithium reaction like this, it is non-active element with respect to lithium, in the removal lithium embedded process of whole alloy, the various change in volume of Ni in can buffer electrode, thus improve the structural stability of electrode material.The present invention adopts the high temeperature chemistry reduction technique; utilize carbon dust as reducing agent; tin oxide, antimony oxide, nickel oxide and carbon dust are evenly mixed, place the sintering furnace that is connected with under the protective atmosphere to carry out sintering, be incubated after 1-3 hour and can obtain end product SnSbNi alloy composite materials with the stove cooling.

The invention has the advantages that technical process is simple, consuming time less, the productive rate height.Synthesize SnSbNi alloy degree of crystallinity height, be 5～500 microns polycrystalline particle, thereby specific area is lower, serious reunion and surface oxidation be difficult for to take place, thereby have reduced the irreversible capacity of negative material.Simultaneously, the tactic pattern of ternary alloy three-partalloy has cushioned the change in volume of material in the removal lithium embedded process, the embedding of taking off of lithium is taken place step by step, and have inactive buffering phase, thereby improved the cyclical stability of material.SnSbNi lithium ion battery negative material specific capacity height, the stable cycle performance prepared, reversible capacity is up to 379mAh/g, and specific capacity remains on about 90% after 10 circulations, and coulombic efficiency is 93%.

Description of drawings

Fig. 1 is the XRD figure of the synthetic SnSbNi of carbon thermal reduction of the present invention, and the atomic ratio of Sn, Sb, Ni is 1: 1: 1, and synthesis temperature is 900 ℃.

Fig. 2 is specific capacity-cycle-index curve of the synthetic SnSbNi of carbon thermal reduction of the present invention, and the atomic ratio of Sn, Sb, Ni is 1: 1: 1, and synthesis temperature is 900 ℃.

Embodiment

Embodiment 1:

With SnO2 (purity＞99.9%), Sb ₂O ₃(purity＞99.9%), Ni ₂O ₃(purity＞99.9%) and activated carbon (purity＞99%) are initial feed, 2: 1: 1 in molar ratio: 10 prepare burden (be equivalent to Sn: Sb: the Ni atomic ratio is 1: 1: 1), after grinding mixture evenly, place that the heating rate with 5 ℃/min is elevated to 900 ℃ under the mobile argon gas atmosphere, be incubated 2 hours, outage naturally cools to room temperature then.The XRD material phase analysis result of gained sample shows that synthetic product is SnSb and NiSb alloy complex, does not have the existence of any oxide impurity phase.

The conductive agent acetylene black that synthetic material is added 10wt%, the binding agent PVDF of 10wt% makes slurry, evenly be applied on the copper platinum, after the oven dry, block circular pole piece, form test cell, carry out the constant current charge-discharge experiment with lithium metal, charging and discharging currents is 100mA/g, and the charging/discharging voltage scope is controlled between the 0.01-1.2V.The initial reversible capacity of SnSb/NiSb negative material of preparation is 379mAh/g, and the specific capacity that circulates after 10 times is 340mAh/g, and capability retention is 90%.

Embodiment 2:

With SnO ₂(purity＞99.9%), Sb ₂O ₃(purity＞99.9%), NiO (purity＞99.9%) and activated carbon (purity＞99%) are initial feed, 4: 1: 2 in molar ratio: 13 prepare burden (atomic ratio that is equivalent to Sn: Ni: Si is 2: 1: 1), after grinding mixture evenly, place under the mobile argon gas atmosphere, heating rate with 10 ℃/min is elevated to 1000 ℃, be incubated 2 hours, outage naturally cools to room temperature then.The XRD material phase analysis of gained sample shows that synthetic product is the Sn/SnSb/NiSb alloy complex, does not have the existence of any oxide impurity phase.The conductive agent acetylene black that synthetic material is added 13 wt%, the binding agent PVDF of 12wt% makes slurry, evenly be applied on the copper platinum, after the oven dry, block circular pole piece, form test cell, carry out the constant current charge-discharge experiment with lithium metal, charging and discharging currents is 100mA/g, and the charging/discharging voltage scope is controlled between the 0.01-1.2V.The initial reversible capacity of the SnSbNi alloy composite anode material of preparation is 389mAh/g.The specific capacity that circulates after 10 times is 343mAh/g, and capability retention is 88%.

Claims

1, a kind of preparation method of high power capacity SnSbNi alloy complex lithium ion battery negative material adopts carbothermic method, utilizes carbon dust as reducing agent, the oxide of reduction tin, antimony and nickel, the alloy complex negative material of preparation different proportion; Technology is:

A, the tin oxide with 100nm-100 μ m, antimony oxide, nickel oxide and activated carbon or carbon black powder carry out the weighing proportioning, the addition of tin oxide and antimony oxide is calculating in 3: 1～1: 3 by Sn and Sb atomic ratio, the addition of nickel oxide accounts for 10～60 atom % of the total alloy amount of Sn+Sb+Ni by Ni, and the addition of activated carbon or carbon black is pressed chemical formula: xSnO ₂+ ySb ₂O ₃+ zNi ₂O ₃+ (2x+3y+3z) C=Sn _xSb _2yNi _2z+ (2x+3y+3z) CO calculates, and with respect to Sn+Sb+Ni, the addition of activated carbon or carbon black all is reduced to CO by the oxygen in the oxide raw material and calculates;

B, employing mechanical dry are mixed or the method for wet mixing mixes raw material; Mixture places the heating furnace that is connected with flowing nitrogen or argon gas atmosphere, reaches temperature required 800～1100 ℃ with 5～30 ℃/minute heating rates, is incubated 1～3 hour; Outage cools to room temperature naturally with the furnace then, obtains end product SnSbNi alloy combination electrode material.

2, in accordance with the method for claim 1, it is characterized in that: with SnO ₂, Sb ₂O ₃And Ni ₂O ₃As raw material, excessive 5～30 atom % of the consumption of C wherein are as reduction protection.