CN103474662A - High-temperature solid phase synthesis method for lithium ion battery anode material Na3V2(PO4)3 - Google Patents

Abstract

The invention relates to a novel storage battery electrode material in the field of new energy, namely a lithium ion battery anode material Na3V2(PO4)3. The material is characterized by being obtained by one step through using a simple solid phase reaction method. The method has the advantages that a preparation process is simple, and the cost is relatively low. As the Na3V2(PO4)3 is relatively high in theoretical capacity, good in stable performance, and relatively low in cost and has huge application potential in a large energy storing device in the future, the Na3V2(PO4)3 is widely concerned by scholars in various countries day by day, and becomes one of frontier research hotspots in the world.

Description

Anode material for lithium-ion batteries Na 3v 2(PO 4) 3the high temperature solid-state synthetic method

Technical field

The present invention relates to utilize high temperature solid-state method to synthesize Na ₃v ₂(PO ₄) ₃anode material for lithium-ion batteries, and carried out relevant electrochemical property test; Result shows, this material is a kind of cell positive material with certain research and application prospect.The new energy materials technical field that belongs to current focus.

Background technology

Lithium ion battery, as the environmental protection electrical storage device of latest generation, comes across early 1990s, once appearance, has just caused rapidly people's concern, and development is swift and violent.Lithium battery has a lot of outstanding advantages, such as operating voltage is high, large, the good cycle of energy density etc., in the electronic equipments such as mobile phone, notebook computer, has a wide range of applications.Positive electrode is the important component part of lithium ion battery, affects to a great extent the performance of battery, and in the sense, it is directly determining the height of battery cost.

At present, the research of high performance lithium ion battery and electrode material thereof is one of focus of the area researches such as electrochemistry, materials chemistry, physics.Simultaneously, along with the extensive application of lithium battery, the consumption of lithium resource also increases sharply, and corresponding meeting causes that cost rises.And being all the sodium ion of I main group and the character of lithium ion has many similarities, sodium ion is fully likely the same with lithium ion constructs a kind of widely used secondary cell.With lithium ion battery, compare, sodium-ion battery has obvious advantage, and as the cost of raw material is lower than lithium ion battery, half-cell prtential is higher than lithium ion battery, thereby security performance obviously is better than lithium ion battery.Recently, the research about anode material of lithium-ion battery has abroad obtained good progress, studies the key that high performance sodium-ion battery positive electrode becomes such battery development.C. Delmas etc. has just studied stratiform Na in early 1980s _xcoO ₂positive electrode, the polarizing voltage due to it between charging and discharging is large especially, causes its energy conversion efficiency not high, has limited the actual scope of application.M. Doeff etc. are at first to having the Na that orthohormbic structure, space group are Pbam _0.44mnO ₂as the sodium-ion battery positive electrode, be studied.Although Na _0.44mnO ₂cycle performance very good, but the actual specific capacity of this material is on the low side, operating voltage is not high yet, has limited its application in the non-aqueous solution sodium-ion battery.NaFePO ₄f, Na ₃v ₂(PO ₄) ₂f ₃, NaVPO ₄f and Na _1.5vOPO ₄f _0.5also obtain broad research Deng fluorinated phosphate salt as the positive electrode of sodium-ion battery positive electrode and hybrid battery, but the preparation process of this class fluorinated phosphate salt is complicated and can produce the fluoro-gas contaminated environment.NASICON class material has Three-dimensional Open ion transport passage, is a class fast ion conducting material.The reported first such as the CAS Institute of Physics Hu Yongsheng of the Chinese Academy of Sciences Na with NASICON structure that coats of carbon ₃v ₂(PO4) ₃/ C composite material, its charge and discharge platform is in the 3.4V left and right.Because it has higher specific capacity, relatively low cost advantage, day by day become one of study hotspot.

Summary of the invention

The object of the invention is, with the synthetic a kind of Olivine-type Cathode Material in Li-ion Batteries Na of solid phase method ₃v ₂(PO ₄) ₃, Na prepared by the method ₃v ₂(PO ₄) ₃chemical property is high, and preparation technology is simple, with low cost, has application prospect preferably.

A kind of anode material for lithium-ion batteries Na of the present invention ₃v ₂(PO ₄) ₃the high temperature solid-state synthetic method, it is characterized in that, include following concrete steps:

A. take sodium oxalate, vanadic oxide, ammonium dihydrogen phosphate, acetylene black by stoichiometric proportion, the mol ratio of primary raw material is: sodium oxalate: vanadic oxide: ammonium dihydrogen phosphate: acetylene black=1.5:1:3:1.1 fully grinds 1 ~ 4 hour in mortar;

B. by the mix powder after above-mentioned abundant grinding, under nitrogen atmosphere, under 600 ~ 900 ℃, calcine 15 ~ 20 h, naturally cool to room temperature, obtain target product.

 

The present invention has the following advantages:

1. employing solid phase method, a step can obtain desired electrode material.

2. replace lithium metal with sodium metal, reduced cost, the simultaneous electrochemical performance is also better.

The accompanying drawing explanation

Fig. 1 is the Na by embodiment 1 preparation ₃v ₂(PO ₄) ₃xRD figure.

Fig. 2 is the Na by embodiment 1 preparation ₃v ₂(PO ₄) ₃sEM figure.

Fig. 3 is the Na by embodiment 1 preparation ₃v ₂(PO ₄) ₃charge-discharge performance figure.

Fig. 4 is the Na by embodiment 1 preparation ₃v ₂(PO ₄) ₃the cycle life performance resolution chart.

Embodiment

Below in conjunction with embodiment, the present invention is described in detail.

embodiment mono-the concrete steps of the present embodiment are as follows:

A. take sodium oxalate 0.3375g by stoichiometric proportion, vanadic oxide 0.3032g, ammonium dihydrogen phosphate 0.5752g, acetylene

Black 0.022g fully grinds 2 hours in mortar;

B. by the mix powder after above-mentioned abundant grinding, under nitrogen atmosphere, under 700 ℃, calcining 15h, naturally cool to room temperature, obtains target product Na ₃v ₂(PO ₄) ₃.

Products therefrom is carried out to Performance Detection, and testing result is shown in following accompanying drawing.

Referring to Fig. 1, Fig. 1 is to Na ₃v ₂(PO ₄) ₃the XRD that characterized figure, by contrast with the XRD base peak, prove with described solid phase method gained be this material, the impurity peaks in XRD figure, be a small amount of Na of remnants ₂c ₂o ₄.

Referring to Fig. 2, Fig. 2 is Na ₃v ₂(PO ₄) ₃sEM figure, as seen from the figure, the synthetic material with this solid phase method, its particle is larger, particle size is at micron order.

Referring to Fig. 3, Fig. 3 is Na ₃v ₂(PO ₄) ₃charge-discharge performance figure, as can be seen from the figure, for the first time to the 5th time, its charge/discharge capacity there is no variation, with the 5th time, compare for the 20 time, though charge/discharge capacity has minimizing, but still keep higher capacity, this illustrates that this composite material has relative stability and higher capacity.

Referring to Fig. 4, Fig. 4 is Na ₃v ₂(PO ₄) ₃the cycle life performance resolution chart, as seen from the figure, Na ₃v ₂(PO ₄) ₃specific discharge capacity first is 105mAh/g, and along with the increase of cycle-index, specific discharge capacity reduces gradually, and through 50 circulations, its specific discharge capacity maintains 60 ~ 65mAh/g, and it has larger specific capacity as seen.

Claims (1)

1. an anode material for lithium-ion batteries Na ₃v ₂(PO ₄) ₃the high temperature solid-state synthetic method, it is characterized in that, the concrete steps of the method are:

A. take sodium oxalate, vanadic oxide, ammonium dihydrogen phosphate, acetylene black by stoichiometric proportion, the mol ratio of primary raw material is: sodium oxalate: vanadic oxide: ammonium dihydrogen phosphate: acetylene black=1.5:1:3:1.1 fully grinds 1 ~ 4 hour in mortar;

B. by the mix powder after above-mentioned abundant grinding, under nitrogen atmosphere, under 600 ~ 900 ℃, calcine 15 ~ 20 h, naturally cool to room temperature, obtain target product.

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