阅读说明：本技术 一种低空位的普鲁士蓝类钠离子电池正极材料及其制备方法 (A kind of prussian blue sodium-ion battery positive material and preparation method thereof of low latitude position ) 是由 姜银珠 王宝琦 于 2019-08-12 设计创作，主要内容包括：本发明公开了一种低空位的普鲁士蓝类钠离子电池正极材料及其制备方法。将亚铁氰化钠的无水溶液缓慢加入到过渡金属元素的无水盐的无水溶液进行沉淀反应,经过离心、洗涤、真空干燥后即制备出所述材料。利用该方法制备的普鲁士蓝类钠离子电池电极材中,每分子式Na<Sub>x</Sub>M[Fe(CN)<Sub>6</Sub>]<Sub>1-y</Sub>□<Sub>y</Sub>·nH<Sub>2</Sub>O中的空位含量y<0.1,使得材料具有高容量,高循环稳定性,高倍率特性等优点。(The invention discloses a kind of prussian blue sodium-ion battery positive materials and preparation method thereof of low latitude position.The anhydrous solution that the anhydrous solution of sodium ferrocyanide is slowly added into the anhydrous salt of transition metal element is subjected to precipitation reaction, the material is prepared after centrifugation, washing, vacuum drying.In prussian blue sodium-ion battery electrode material using this method preparation, per molecule formula Na x M[Fe(CN) 6 ] 1‑y □ y ·nH 2 Vacancy content y < 0.1 in O, so that material has the advantages that high capacity, high circulation stability, high-rate characteristics.)

1. a kind of prussian blue sodium-ion battery positive material of low latitude position, it is characterised in that: the prussian blue sodium from The chemical formula of sub- cell positive material is Na_xM[Fe(CN)₆]_1-y□_y·nH₂O, wherein M represents transition metal element, and is represented Vacancy in material, vacancy content y≤0.1 in molecular formula, sodium content 1.5 < x < 2 are coordinated water content 0 < n < 1.

2. a kind of prussian blue sodium-ion battery positive material of low latitude position as described in claim 1, it is characterised in that: institute It states transition metal element and is selected from one or more of vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc.

3. a kind of method of preparation low latitude position prussian blue sodium-ion battery positive material as claimed in claim 1 or 2, Be characterized in that the following steps are included:

Ten hydration sodium ferrocyanides are dissolved in nonaqueous solvents, sodium ferrocyanide precursor liquid A is obtained；

The anhydrous divalent salts of transition metal M are dissolved in nonaqueous solvents, precursor liquid B identical with precursor liquid A concentration is configured to；Institute The precursor liquid B of preparation is identical as precursor liquid A volume；

Precursor liquid A is put into reaction vessel, precursor liquid B, which is added in reactor by peristaltic pump with fixed flow rate, to be precipitated Reaction；In entire reaction process, it is passed through protective gas in reactor, lasting stirring is imposed with magnetic stirring apparatus, and pass through water Bath mode keeps constant temperature；It is run out of to precursor liquid B, reaction comes to an end；

By the suspension centrifugation in reactor, then rinsed with deionized water, repeatedly after to be put into vacuum drying oven dry, 120^oC Temperature and 100Pa pressure under dry 12 hours to get to the prussian blue sodium-ion battery anode material of low latitude position Material.

4. a kind of preparation method of the prussian blue sodium-ion battery positive material of low latitude position as claimed in claim 3, Be characterized in that: the transition metal M is one or more of vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, the transition gold The anhydrous divalent salts for belonging to M are divalent sulfates, nitrate or the chloride of the M element without the crystallization water.

5. a kind of preparation method of the prussian blue sodium-ion battery positive material of low latitude position as claimed in claim 3, Be characterized in that: the nonaqueous solvents is ethyl alcohol, ethylene glycol or glycerol, and the configuration concentration of precursor liquid A described in step 1) is 20mmol/L。

6. a kind of preparation method of the prussian blue sodium-ion battery positive material of low latitude position as claimed in claim 3, Be characterized in that: the protective gas being passed through in reactor in step 3) is nitrogen or argon gas, and the flow velocity for being passed through protective gas is 20 ~100mL/min.

7. a kind of preparation method of the prussian blue sodium-ion battery positive material of low latitude position as claimed in claim 3, Be characterized in that: the thermostat temperature of reactor is 0 in step 3)^oC~100^oC。

8. a kind of preparation method of the prussian blue sodium-ion battery positive material of low latitude position as claimed in claim 3, Be characterized in that: the fixed flow rate that precursor liquid B is added in reactor in step 3) is 5mL/h~100mL/h.

9. a kind of preparation method of the prussian blue sodium-ion battery positive material of low latitude position as claimed in claim 3, Be characterized in that: centrifugal rotational speed is 3000~15000rpm in step 4), and centrifugation time is 3~15 minutes.

Technical field

The present invention relates to a kind of sodium ion battery electrode materials and preparation method thereof, belong to field of energy source materials.

Background technique

Quick increasing since lithium ion battery enters electric car and extensive energy storage field, for lithium ion battery demand The long key raw material having resulted in lithium ion battery, such as the price spikes of lithium mine and cobalt ore.In order to alleviate lithium resource The circumstances that shortage and lithium valence rise violently, people have put into a large amount of research on " non-lithium " battery, and wherein sodium-ion battery is due to sodium It is resourceful and cheap attracted a large amount of concern.Sodium and lithium are located at same main group, and physicochemical property is close, thus construct and The similar sodium-ion battery of lithium ion battery working principle is feasible.

Sodium-ion battery is a kind of Na ion concentration difference battery, Na when charging⁺Cathode is entered by electrolyte, electronics is logical External circuit compensation is crossed to cathode, it is ensured that charge balance.Then on the contrary, Na when electric discharge⁺Anode is entered by electrolyte, electronics passes through External circuit compensation ensures charge balance to anode.

The property of electrode material plays conclusive effect for the performance of sodium-ion battery.Sodium ion electricity common at present Specific capacity with higher and preferable dynamics are special for pond negative electrode material such as hard carbon, tin, antimony and alloy material etc. Property.Therefore, developing high performance sodium-ion battery positive material just becomes the focus on research direction of sodium-ion battery development.Research The inorganic sodium electricity positive electrode of most commonly used three classes includes layered metal oxide, polyanionic compound and prussian blue Like object.Wherein, it is reversible that the Prussian-blue for opening network structure framework with firm three-dimensional can permit sodium ion Insertion abjection provides the up to theoretical capacity of 170mAh/g when redox reaction activity (M element have), and store up sodium current potential compared with It is high.Meanwhile the limitation migrated compared to the oxygen-containing lattice of layered metal oxide and polyanionic compound for sodium ion compared with Greatly, the active force in the lattice of Prussian-blue between cyanogen root and sodium ion is weaker so that when the diffusion of sodium ion by The resistance arrived is smaller.In addition, the synthesis process of Prussian-blue is easy mild, it is not necessarily to high temperature sintering, relatively other two The preparation cost of class material is also lower.

In perfect Prussian-blue frame, metal octahedron is by cyano-bridged.Metal-carbon is octahedra and golden Category-nitrogen is octahedra staggered to constitute the three-dimensional network as shown in attached drawing 1 (a).But, sub- in general synthesis process Iron cyanogen root vacancy is frequently accompanied by the rapid precipitation of Prussian-blue and generates.Which results in the water in synthetic environment Molecule occupies six angles of octahedral voids to form so-called constitution water, as shown in attached drawing 1 (b).Transition metal ions M²⁺ It easily carries out cooperatively forming hydrated ion with hydrone in aqueous solution.Hydrated ion is reacting the general Shandong of building with ferrous cyanide ion The water of coordination of carrying can be introduced into the lattice of product when scholar's basket frame structure.Due to the presence of water of coordination, lead to this The ferrous cyanogen root that should cooperate with copper ion cannot be introduced into lattice seat, so that it is empty to produce a large amount of ferrous cyanogen root in lattice Position.This makes water content in product and vacancy content higher.In the product of this high vacancy content, redox active position Point greatly reduces, and then leads to the reduction of prussian blue electrode capacity.Secondly, the migration of sodium ion also rely on it is Prussian blue The integrality of frame is opened, calculated result shows that migration path of the sodium ion in prussian blue electrode is from the one of superlattices A face heart position is transferred to the W type path of adjacent face heart position.Once ferrous cyanogen root vacancy occurs, will lead to cause to migrate road Diameter it is discontinuous, the insertion and deintercalation of sodium ion can be interfered.Finally, the presence of defect and constitution water can also be such that side reaction is easier Occur, the cycle life of electrode material is adversely affected.Therefore, the structural integrity of Prussian-blue how is improved Property, vacancy content and Hydroxyl content therein are reduced, so that the specific capacity of electrode material is improved, multiplying power property and stable circulation Property is the research emphasis of current prussian blue positive electrode.

In order to realize the above target, recent domestic researcher has done a large amount of work, such as structure is set Meter, conductive material is compound or coats, element doping or substitution etc..These work can be to the specific capacity of electrode, multiplying power property Certain improvement result is played with cyclical stability.But since the synthesis process of Prussian-blue is mainly in water It is carried out in solution, so predecessor can cooperate with being difficult to avoid that with hydrone, leads to the generation in vacancy, to influence electrode The specific capacity of material, multiplying power property and cyclical stability.So how to reduce the vacancy in material by the control of synthesis condition Content is to promote the specific capacity of material, the problem of multiplying power property and cyclical stability are current urgent need to resolve.

Summary of the invention

The purpose of the present invention is overcome the deficiencies of the prior art and provide a kind of prussian blue sodium-ion battery of low latitude position Positive electrode and preparation method thereof.

The present invention provides a kind of prussian blue sodium-ion battery positive material of low latitude position, the materials chemistry formula is Na_xM[Fe(CN)₆]_1-y□_y·nH₂O, wherein M represents transition metal element, and represents the vacancy in material, in per molecule formula Vacancy content y < 0.1, sodium content 1.5 < x < 2 are coordinated water content 0≤n < 1.Wherein transition metal element M be selected from vanadium, chromium, manganese, One or more of iron, cobalt, nickel, copper, zinc.

The present invention also provides the preparation methods of above-mentioned prussian blue sodium-ion battery positive material, make prussian blue The precipitation reaction of compound occurs in water-less environment, reduces the probability that transition metal ions and hydrone cooperate, from And achieve the effect that reduce material Vacancy and Hydroxyl content.The following steps are included:

1) ten hydration sodium ferrocyanides are dissolved in nonaqueous solvents, obtain sodium ferrocyanide precursor liquid A；The configuration of precursor liquid A Concentration is 20mmol/L；

2) the anhydrous divalent salts of transition metal M are dissolved in nonaqueous solvents, are configured to precursor liquid identical with precursor liquid A concentration B；Prepared precursor liquid B is identical as precursor liquid A volume；

3) precursor liquid A is put into reaction vessel, precursor liquid B is added in reactor with fixed flow rate by peristaltic pump and is carried out Precipitation reaction；

In entire reaction process, it is passed through protective gas in reactor, lasting stirring is imposed with magnetic stirring apparatus, and pass through water-bath Mode keeps constant temperature；

It is run out of to precursor liquid B, reaction comes to an end；

4) suspension in reactor is centrifuged, then is rinsed with deionized water, repeatedly after dry, the In that is put into vacuum drying oven 120^o12 hours are dried at the temperature of C and the pressure of 100Pa to get the prussian blue sodium-ion battery of the low latitude position is arrived just Pole material.

Further, the M element is one or more of vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, the M element Anhydrous divalent salts be M element divalent sulfates, nitrate or chloride, the nonaqueous solvents is ethyl alcohol, and ethylene glycol is sweet Oil.

Preferably, the protective gas being passed through in reaction vessel is nitrogen or argon gas, and flow velocity is 20~100mL/ min。

Further, the heating temperature of reaction vessel is 0 in step 3)^oC~100^oC。

Further, it is 5mL/h~100mL/h that step 3) precursor liquid B, which is added to the flow velocity in reaction vessel,.

Further, the centrifugal rotational speed of step 4) is 3000~15000rpm, and centrifugation time is 3~15 minutes.

Novel sodium-ion battery prussian blue positive electrode of the invention is had excellent performance, can be used for substituting existing sodium from Sub- cell positive material, has a good application prospect.The positive electrode has height structural intergrity, Na in per molecule formula_xM [Fe(CN)₆]_1-y□_y·nH₂O vacancy content y < 0.1.Low latitude position amount ensure that material has sufficient redox active position Point ensure that electrode material has height ratio capacity；Meanwhile low latitude position amount ensures the continuous of sodium ion diffusion admittance, so that electric Pole material has good multiplying power property；In addition, low vacancy content is but also Hydroxyl content reduction, reduces side reaction Probability, improve the cycle life of electrode material.Preparation process simple possible of the invention, it is low in cost, it can be generalized to In the preparation of other kinds of Prussian-blue electrode material, there is certain universality.

Detailed description of the invention

Fig. 1 (a) perfection Prussian-blue lattice and (b) defective Prussian-blue lattice.

Fig. 2 is the synthesizer of low latitude position of the present invention prussian blue sodium-ion battery positive material.

Fig. 3 is the iron-based Prussian blue first charge-discharge curve in the position of low latitude made from embodiment 1, charging and discharging currents density 100 mA g^-1。

Specific embodiment

Reaction is added when preparing the prussian blue sodium-ion battery positive material of low latitude position in the present invention for convenience Object, controls reaction process, and various embodiments of the present invention use reaction unit as shown in Figure 2 and carry out precipitation reaction.Three necks are burnt Bottle is that reaction vessel wherein fills precursor liquid A；Precursor liquid B is connected by the conduit with peristaltic pump with reaction vessel.Reaction is held Device is passed through protection gas during the reaction, and lasting stirring is imposed with magnetic stirrer, is bathed by water (ice) and keeps reaction process Middle temperature it is constant.

The present invention is described in detail below by specific embodiment.