CN102299314A - Preparation method of positive electrode material spinel LiMn2O4 for lithium ion battery - Google Patents

Abstract

The invention relates to a preparation method of a positive electrode material spinel LiMn2O4 for a lithium ion battery. A sol-gel synthetic method without chelating agents which is adopted in the invention is that the positive electrode material spinel LiMn2O4 is prepared by dissolving lithium citrate and manganese acetate in deionized water to obtain a uniform sol system, and carrying out operations of drying, grinding, sintering and the like. The preparation method of the invention has the advantage of simple technology, the particle size of the preparative material uniformly distributes, the initial discharge specific capacity of the preparative material which is high is higher than 135mAh/g, and the electrochemical performance of the preparative material is stable.

Description

Spinelle LiMn＜sub〉2＜/sub〉O＜sub〉4＜/sub〉preparation method of anode material for lithium-ion batteries

Technical field

The present invention relates to spinelle LiMn ₂O ₄The preparation method of positive electrode belongs to the lithium ion battery material preparing technical field.

Background technology

As the positive electrode of lithium ion battery, spinel-type LiMn ₂O ₄Enjoy and gaze at.The manganese aboundresources, cheap, environmental friendliness; LiMn ₂O ₄Have high potential, the excellent safety energy is considered to the alternative commercialization LiCoO of tool potentiality ₂One of anode material for lithium-ion batteries.At present synthetic LiMn ₂O ₄The method of positive electrode mainly contains solid phase method and liquid phase method.Solid phase method, simple such as patent CN1169247C synthesis technique, cost is low.But the material homogeneity that solid phase method synthesizes is poor, and often contains impurity.Liquid phase method comprises the precipitation method, sol-gel process etc., forms homogeneous as patent CN1142606C synthetic material, and particle diameter is even.But traditional precipitation method and sol-gal process usually need to add precipitation reagent or chelating agent, the process complexity, and cost is higher.Simultaneously, as anode material for lithium-ion batteries, LiMn ₂O ₄Mainly exist the problems such as structural instability and cycle performance difference.

Summary of the invention

The present invention is directed to LiMn ₂O ₄Mainly exist the problem of structural instability and cycle performance difference, have the know-why of the double action that lithium source and chelating agent are provided concurrently according to lithium citrate, propose a kind of chelating agent that need not to add, the spinelle LiMn that the preparation particle diameter is even, chemical property is good ₂O ₄The method of anode material for lithium-ion batteries.Main contents comprise:

(1) lithium citrate and manganese acetate are dissolved in the deionized water according to mol ratio at 1: 6, obtain sol system;

(2) the sol system oven dry that step (1) is made, the gel after will drying again grinds, and makes LiMn ₂O ₄Precursor powder;

(3) LiMn that step (2) is made ₂O ₄Precursor powder places the high temperature furnace of air atmosphere, and at 600～900 ℃ of lower sintering 8～15h, the rate of temperature fall with 1～5 ℃/min is cooled to room temperature subsequently, namely obtains spinelle LiMn ₂O ₄Anode material for lithium-ion batteries.

Technological merit of the present invention:

(1) technology simple, with short production cycle, be easy to industrialization;

(2) LiMn of preparation ₂O ₄Material homogeneity is good, specific capacity is high, cycle performance is good.

Description of drawings

The spinelle LiMn of Fig. 1 for making by embodiment 2 technologies ₂O ₄The XRD figure of lithium ion secondary battery anode material.

The spinelle LiMn of Fig. 2 for making by embodiment 2 technologies ₂O ₄The SEM figure of lithium ion secondary battery anode material.

The spinelle LiMn of Fig. 3 for making by embodiment 2 technologies ₂O ₄The first charge-discharge curve map of lithium ion secondary battery anode material under 0.1C, voltage range is 3.0～4.3V, electrolyte is the LiPF of 1.0mol/L ₆(EC/DMC=1: 1, volume ratio).

The spinelle LiMn of Fig. 4 for making by embodiment 2 technologies ₂O ₄30 the cyclic curve figures of lithium ion secondary battery anode material under 0.5C.

Embodiment

Following example will further specify the present invention.

Embodiment 1

Be to take by weighing 4.70g Li at 1: 6 according to mol ratio ₃C ₆H ₅O ₃4H ₂O, 24.51g Mn (CH ₃COO) ₂4H ₂O is dissolved in deionized water with the two and forms uniform sol system, again colloidal sol is carried out microwave drying and gets xerogel, then xerogel is ground, and namely gets precursor powder.In air atmosphere, precursor powder is carried out sintering, heat treatment temperature is 900 ℃, and insulation 10h, is down to room temperature with the speed of 5 ℃/min subsequently and namely makes spinelle LiMn ₂O ₄Lithium ion secondary battery anode material.With resulting material is positive active material, and metal lithium sheet is that negative pole is assembled into Experimental cell, carries out charge-discharge test in 3.0～4.3V interval, records it under 0.1C, and first discharge specific capacity is 96.9mAh/g; 0.5C down, 30 circulation back specific discharge capacities decays to 9% of initial specific capacity.

Embodiment 2

Be to take by weighing 4.70g Li at 1: 6 according to mol ratio ₃C ₆H ₅O ₃4H ₂O, 24.51g Mn (CH ₃COO) ₂4H ₂O is dissolved in deionized water with the two and forms uniform sol system, again colloidal sol is carried out microwave drying and gets xerogel, then xerogel is ground, and namely gets precursor powder.In air atmosphere, precursor powder is carried out sintering, heat treatment temperature is 800 ℃, and insulation 10h, is down to room temperature with the speed of 2 ℃/min subsequently and namely makes spinelle LiMn ₂O ₄Lithium ion secondary battery anode material.Resulting material is carried out particle size distribution test, and the result shows that its particle size distribution is even, D ₅₀Be 1.1 μ m.With resulting material is positive active material, and metal lithium sheet is that negative pole is assembled into Experimental cell, carries out charge-discharge test in 3.0～4.3V interval, records it under 0.1C, and first discharge specific capacity is 137.8mAh/g; 0.5C down, 30 circulation back specific discharge capacities decays to 5% of initial specific capacity.

Embodiment 3

Be to take by weighing 4.70g Li at 1: 6 according to mol ratio ₃C ₆H ₅O ₃4H ₂O, 24.51g Mn (CH ₃COO) ₂4H ₂O is dissolved in deionized water with the two and forms uniform sol system, again colloidal sol is carried out microwave drying and gets xerogel, then xerogel is ground, and namely gets precursor powder.In air atmosphere, precursor powder is carried out sintering, heat treatment temperature is 700 ℃, and insulation 12h, is down to room temperature with the speed of 2 ℃/min subsequently and namely makes spinelle LiMn ₂O ₄Lithium ion secondary battery anode material.Resulting material is carried out the XRD test, and the result shows that it has uniform spinel structure, and chemical composition is single.With resulting material is positive active material, and metal lithium sheet is that negative pole is assembled into Experimental cell, carries out charge-discharge test in 3.0～4.3V interval, records it under 0.1C, and first discharge specific capacity is 119.3mAh/g; 0.5C down, 30 circulation back specific discharge capacities decays to 6% of initial specific capacity.

Embodiment 4

Be to take by weighing a certain amount of Li at 1: 6 according to mol ratio ₃C ₆H ₅O ₃4H ₂O, Mn (CH ₃COO) ₂4H ₂O is dissolved in deionized water with the two and forms uniform sol system, again colloidal sol is carried out microwave drying and gets xerogel, then xerogel is ground, and namely gets precursor powder.In air atmosphere, precursor powder is carried out sintering, heat treatment temperature is 600 ℃, and insulation 12h, is down to room temperature with the speed of 1 ℃/min subsequently and namely makes spinelle LiMn ₂O ₄Lithium ion secondary battery anode material.With resulting material is positive active material, and metal lithium sheet is that negative pole is assembled into Experimental cell, carries out charge-discharge test in 3.0～4.3V interval, records it under 0.1C, and first discharge specific capacity is 101.4mAh/g; 0.5C down, 30 circulation back specific discharge capacities decays to 6% of initial specific capacity.

Claims (1)

1. spinelle LiMn ₂O ₄The preparation method of anode material for lithium-ion batteries comprises the steps:

(1) lithium citrate and manganese acetate is soluble in water according to mol ratio 1: 6, obtain sol system;

(2) sol system that step (1) is made carries out drying and obtains xerogel, xerogel is ground again, and makes LiMn ₂O ₄Precursor powder;

(3) LiMn that step (2) is made ₂O ₄Precursor powder places the high temperature furnace of air atmosphere, and at 600～900 ℃ of lower sintering 8～15h, the rate of temperature fall with 1～5 ℃/min is cooled to room temperature subsequently, namely obtains spinelle LiMn ₂O ₄Anode material for lithium-ion batteries.

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