KR101319380B1 - Solid electrolyte, rechargeable lithium battery comprising the same, method for preparing solid electrolyte particles and solid electrolyte particles - Google Patents

Abstract

A solid electrolyte is provided comprising Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles having a true density of 2.20 to 2.50 g / cm ₃ .

Description

Solid electrolyte, lithium secondary battery comprising the solid electrolyte, the method for producing the solid electrolyte particles and the solid electrolyte particles TECHNICAL FIELD

It relates to a solid electrolyte, a lithium secondary battery containing the solid electrolyte, a method for producing the solid electrolyte particles, and particles for a solid electrolyte.

A lithium secondary battery, which has recently been spotlighted as a power source for portable electronic devices, has a discharge voltage twice as high as that of a conventional battery using an alkaline aqueous solution, resulting in high energy density.

However, as the safety of the organic electrolyte in the lithium secondary battery is a problem, all-solid-state batteries without using the organic electrolyte have emerged. The most important thing in all solid-state batteries is a solid electrolyte, which can be roughly divided into a polymer solid electrolyte and a ceramic solid electrolyte.

Conventional ceramic solid electrolyte synthesis mainly consists of a solid phase method. In the case of synthesizing by the solid phase method, the heat treatment temperature is increased while the composite phase is synthesized, and the particles are coarse. In addition, the material synthesized by the solid phase method has a high porosity and grain boundary resistance, which adversely acts in terms of ion conductivity.

One embodiment of the present invention to provide a ceramic solid electrolyte having a high ion conductivity.

Another embodiment of the present invention is to provide a lithium secondary battery including a ceramic solid electrolyte having a high ion conductivity.

Another embodiment of the present invention is to provide a method for producing particles for a ceramic solid electrolyte having a high ion conductivity.

One aspect of the invention provides a solid electrolyte comprising Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x≤1) particles having a true density of 2.20 to 2.50 g / cm ₃ do.

The true density of the Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles may be 77 to 80% by volume.

The Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles may be powdery.

The Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x≤1) particles may be synthesized by the sol-gel method.

D50 of the primary particles synthesized by the sol-gel method may have a particle size distribution of 250 nm to 500 nm and D90 of 350 nm to 700 nm.

The ionic conductivity of the solid electrolyte may be 2.33 × 10 ⁻⁴ S / cm to 2.43 × 10 ⁻⁴ S / cm at room temperature.

Another aspect of the invention the negative electrode including a negative electrode active material; A cathode comprising a cathode active material; And it provides a lithium secondary battery comprising the solid electrolyte.

Another aspect of the present invention is to prepare a mixture by mixing a first mixed solution comprising a lithium raw material and a PO ₄ raw material and a second mixed solution comprising an alcohol, a complexing agent and a titanium alkoxide; Heating the mixture at 40 to 80 ° C. to form a chelate / metal sol; Heating the sol at 200 to 300 ° C. to form a gel precursor; And calcining the gel precursor at 650 to 950 ° C. for a method of preparing Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles for a solid electrolyte. to provide.

The first mixed solution may further include an aluminum raw material.

Another aspect of the present invention provides Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x≤1) particles for a solid electrolyte prepared by the above method.

The true density of the Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles for the solid electrolyte may be 2.20 to 2.50 g / cm 3.

The true density of the Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles for the solid electrolyte may be 77 to 80% by volume.

Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles for a solid electrolyte having improved ion conductivity, and the lithium secondary battery including the solid electrolyte particles A process such as pulverization is unnecessary, and the solid electrolyte application process can be simplified.

1 is a SEM image of Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x≤1) particles synthesized according to an embodiment of the present invention.
2 is a SEM photograph of Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x≤1) particles synthesized according to a comparative example of the present invention.
3 is a graph illustrating ion conductivity measurements of Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles synthesized according to the Examples and Comparative Examples. to be.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, by which the present invention is not limited and the present invention is defined only by the scope of the claims to be described later.

In one embodiment of the invention, 2.20 to 2.50 Provided are Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles for a solid electrolyte, which realize a true density of g / cm ₃ .

The Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles for the solid electrolyte may be synthesized by the sol-gel method.

In another embodiment of the present invention, preparing a mixture by mixing a first mixed solution comprising a lithium raw material and a PO ₄ raw material and a second mixed solution including an alcohol, a complexing agent and a titanium alkoxide; Heating the mixture at 40 to 80 ° C. to form a chelate / metal sol; Heating the sol at 200 to 300 ° C. to form a gel precursor; And Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) for the solid electrolyte, by the manufacturing method comprising the step of firing the gel precursor at 650 to 950 ° C. Particles can be synthesized.

The first mixed solution may further include an aluminum raw material. When the first mixed solution includes an aluminum raw material, particles for solid electrolyte Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 <x≤1) may be synthesized and aluminum When not including the raw material, x = 0 in the Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x≤1) particles for the solid electrolyte, that is, LiTi ₂ (PO ₄ ) ₃ can be synthesized.

In order to prepare the first mixed solution, for example, HNO ₃ may be mixed as a predetermined amount when mixed with water to dissolve each raw material, a lithium raw material, and a PO ₄ raw material to prepare as an aqueous metal salt solution.

Preferably, the firing temperature may be 750 to 800 ℃.

Since the manufacturing method is performed at a relatively low process temperature, the particle size may be smaller than that of the high temperature process.

As the nickel raw material, for example, a nickel compound such as nickel sulfate, nickel nitrate, or the like may be used, or two or more kinds thereof may be mixed and used. Preferably nickel sulfate may be used.

As the PO ₄ raw material, for example, a phosphate compound such as NH ₄ H ₂ PO ₄ , (NH ₄ ) ₂ HPO ₄ , (NH ₄ ) ₃ PO ₄ , H ₃ PO _4, or the like may be used. May be used.

As the aluminum raw material, for example, Al (NO ₃ ) ₃ × 9H ₂ O may be used.

As the alcohol in the second mixed solution, alcohols such as methanol and ethanol may be used.

The complexing agent in the two mixed solutions may be at least one selected from the group consisting of ammonia, ethylenediamine, acetic acid and acetylacetone.

In another embodiment of the present invention, D50 of the primary particles synthesized by the method of preparing the sol-gel method may have a particle size distribution of 250 nm to 500 nm and D90 of 350 nm to 700 nm. D50 means 50% -point cumulative particle size distribution and D90 means 90% -point cumulative particle size distribution.

As described above, Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x≤1) particles for solid electrolyte synthesized by the above production method have a small particle size and high density powder. Li having a true density in the above range is suitable for forming a layer, and more compact sintering is possible as particles of smaller size are synthesized as compared to when manufactured by another manufacturing method, for example, a solid phase method. _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles can be realized.

The solid electrolyte including Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x ≦ 1) particles prepared as described above has a small grain boundary resistance, thereby improving ion conductivity.

Since the Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x≤1) particles synthesized by the above method are small and uniform in size, the packing is more excellent, and Li _{( 1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x≤1) can be implemented so that the true density is 77 to 80% by volume relative to the theoretical density of the particles.

In another embodiment of the invention, the ionic conductivity of the solid electrolyte comprising the Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x≤1) particles is room temperature (about 25 ° C) 2.33 × 10 ^-4 S / cm to 2.43 × 10 ^-4 S / cm.

In another embodiment of the invention, the negative electrode including a negative electrode active material; A cathode comprising a cathode active material; And it provides a lithium secondary battery comprising a solid electrolyte comprising the Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x≤1) particles.

Since the lithium secondary battery uses a solid electrolyte having improved ion conductivity, when applied as a solid electrolyte to an all-solid-state battery, the lithium secondary battery shows excellent charge and discharge characteristics such as an increase in capacity and an improvement in life characteristics. In particular, since the particle size is small, it is easy to widen the contact area with the active material in the process, which is an advantageous condition for charging and discharging by expanding the ion transport path.

In a battery system other than an all-solid-state battery, when coated on the surface of a material in the battery, it can be used as a coating layer that plays a role of ion conduction while reducing side reaction of the material surface.

The negative electrode includes a current collector and a negative active material layer formed on the current collector, and the negative active material layer includes a negative active material.

The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, a lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

As a material capable of reversibly intercalating / deintercalating lithium ions, any carbonaceous anode active material commonly used in lithium ion secondary batteries can be used as the carbonaceous material. Typical examples thereof include crystalline carbon , Amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in the form of amorphous, plate-like, flake, spherical or fibrous type. Examples of the amorphous carbon include soft carbon (soft carbon) Or hard carbon, mesophase pitch carbide, fired coke, and the like.

Examples of the lithium metal alloy include lithium and a metal such as Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Alloys may be used.

Examples of the material capable of doping and undoping lithium include Si, SiO _x (0 <x <2), Si-M alloys (wherein M is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, Rare earth elements or combinations thereof, not Si), Sn, SnO ₂ , Sn-M (wherein M is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, or a combination thereof, Sn is not used), and at least one of these and SiO ₂ may be mixed and used. As the element M, Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, , Se, Te, Po, or a combination thereof.

Examples of the transition metal oxide include vanadium oxide, lithium vanadium oxide, and the like.

 The negative electrode active material layer also includes a binder, and may optionally further include a conductive material.

The binder serves to adhere the anode active material particles to each other and to adhere the anode active material to the current collector. Typical examples thereof include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, Such as polyvinyl chloride, polyvinyl fluoride, polymers comprising ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, Styrene-butadiene rubber, epoxy resin, nylon, and the like may be used, but the present invention is not limited thereto.

The conductive material is used for imparting conductivity to the electrode. Any material can be used as long as it does not cause any chemical change in the battery. Examples of the conductive material include natural graphite, artificial graphite, carbon black, acetylene black, , Carbon-based materials such as carbon fibers; Metal powders such as copper, nickel, aluminum, and silver, or metal-based materials such as metal fibers; Conductive polymers such as polyphenylene derivatives; Or a mixture thereof may be used.

The current collector may be a copper foil, a nickel foil, a stainless steel foil, a titanium foil, a nickel foil, a copper foil, a polymer substrate coated with a conductive metal, or a combination thereof.

The anode includes a current collector and a cathode active material layer formed on the current collector.

As the cathode active material, a compound capable of reversibly intercalating and deintercalating lithium (a lithiated intercalation compound) can be used. Concretely, it is possible to use at least one of complex oxides of cobalt, manganese, nickel or a combination of metals and lithium, and specific examples thereof include compounds represented by any one of the following formulas. Li _a A _{1 - b} R _b D ₂ wherein, in the formula, 0.90? A? 1.8 and 0? B? 0.5; Li _a E _{1 - b} R _b O _{2 - c} D _c , wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, and 0 ≤ c ≤ 0.05; LiE _{2 - b} R _b O _{4 - c} D _{c where} 0? B? 0.5, 0? C? 0.05; Li _a Ni _{1 -b- c} Co _b R _c D _{α where} 0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05, and 0 <α ≦ 2; Li _a Ni _{1- b c} Co _b R _c O _{2 -?} Z _? Wherein 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05 and 0 <? Li _a Ni _{1 -b- c} Co _b R _c O _{2 - ?} Z ₂ wherein 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, and 0 <? Li _a Ni _{1 -b- c} Mn _b R _c D _? Wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, and 0 <? Li _a Ni _{1 -b- c} Mn _b R _c O _{2 - ?} Z _{? Where the} 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05 and 0 <? Li _a Ni _{1 -b- c} Mn _b R _c O _{2 - ?} Z ₂ wherein 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05 and 0 <? Li _a Ni _b E _c G _d O ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, and 0.001 ≤ d ≤ 0.1; Li _a Ni _b Co _c Mn _d GeO ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, and 0.001 ≤ e ≤ 0.1; Li _a NiG _b O ₂ (in the above formula, 0.90? A? 1.8 and 0.001? B? 0.1); Li _a CoG _b O ₂ (in the above formula, 0.90? A? 1.8 and 0.001? B? 0.1); Li _a MnG _b O ₂ wherein, in the above formula, 0.90? A? 1.8 and 0.001? B? 0.1; Li _a Mn ₂ G _b O ₄ (in the above formula, 0.90? A? 1.8 and 0.001? B? 0.1); QO _2; QS ₂ ; LiQS ₂ ; V ₂ O ₅ ; LiV ₂ O ₅ ; LiTO ₂ ; LiNiVO _4; Li _(3-f) J ₂ (PO ₄ ) ₃ (0? F? 2); Li _(3-f) Fe ₂ (PO ₄ ) ₃ (0? F? 2); And LiFePO _4.

In the above formula, A is Ni, Co, Mn or a combination thereof; R is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element or a combination thereof; D is O, F, S, P or a combination thereof; E is Co, Mn or a combination thereof; Z is F, S, P or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V or a combination thereof; Q is Ti, Mo, Mn or a combination thereof; T is Cr, V, Fe, Sc, Y or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu or a combination thereof.

Of course, a compound having a coating layer on the surface of the compound may be used, or a compound having a coating layer may be mixed with the compound. The coating layer may comprise, as a coating element compound, an oxide, a hydroxide of a coating element, an oxyhydroxide of a coating element, an oxycarbonate of a coating element, or a hydroxycarbonate of a coating element. The compound constituting these coating layers may be amorphous or crystalline. The coating layer may contain Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr or a mixture thereof. The coating layer forming step may be carried out by any of coating methods such as spray coating, dipping, and the like without adversely affecting the physical properties of the cathode active material by using these elements in the above compound. It is a content that can be well understood by people engaged in the field, so detailed explanation will be omitted.

The cathode active material layer also includes a binder and a conductive material.

The binder serves to adhere the positive electrode active material particles to each other and to adhere the positive electrode active material to the current collector. Typical examples thereof include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl Polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-acrylonitrile, styrene-butadiene rubber, Butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, and the like, but not limited thereto.

The conductive material is used for imparting conductivity to the electrode. Any conductive material can be used without causing any chemical change in the battery. Examples of the conductive material include natural graphite, artificial graphite, carbon black, acetylene black, Metal powders such as black, carbon fiber, copper, nickel, aluminum, and silver, metal fibers, and the like, and conductive materials such as polyphenylene derivatives may be used alone or in combination.

As the current collector, Al may be used, but the present invention is not limited thereto.

The negative electrode and the positive electrode are prepared by mixing an active material, a conductive material and a binder in a solvent to prepare an active material composition, and applying the composition to a current collector. The method of manufacturing the electrode is well known in the art, and therefore, a detailed description thereof will be omitted herein. N-methylpyrrolidone may be used as the solvent, but is not limited thereto.

The electrolyte is a solid electrolyte as described above.

Depending on the type of the lithium secondary battery, a separator may exist between the positive electrode and the negative electrode. The separator may be polyethylene, polypropylene, polyvinylidene fluoride or a multilayer film of two or more thereof. The separator may be a polyethylene / polypropylene double layer separator, a polyethylene / polypropylene / polyethylene triple layer separator, a polypropylene / It is needless to say that a mixed multilayer film such as a propylene three-layer separator and the like can be used.

The manufacturing method of the lithium secondary battery is not particularly limited and may be manufactured by a known method. For example, first, an active material composition is coated and dried on a positive electrode current collector to form a positive electrode active material layer to prepare a positive electrode. Separately, a negative electrode is made by forming a negative electrode active material layer by rolling a lithium metal or a lithium alloy as a negative electrode active material on a negative electrode current collector. The solid electrolyte is interposed between the positive electrode and the negative electrode, and then stacked in this order and sealed under vacuum conditions to obtain a lithium secondary battery.

Hereinafter, examples and comparative examples of the present invention will be described. The following embodiments are only examples of the present invention, and the present invention is not limited to the following embodiments.

( Example )

Example  One

0.961 g of Li ₂ CO _3, 2.251 g of Al (NO ₃ ) ₃ .9H ₂ O and 7.923 g of NH ₄ H ₂ PO ₄ were dissolved in ₇ ml of HNO ₃ to prepare an aqueous metal salt solution. On the other hand, a mixed solution of ₉ ml of ethanol, 3 ml of acetylacetone and 11.57 g of Ti (OC ₄ H ₉ ) ₄ was prepared and then mixed with the aqueous metal salt solution. The mixture was heated at 80 ° C. to form a chelate / metal sol. The formed sol was heated at 300 ° C. to form a gel precursor. The gel precursor to a calcination at 950 ℃ Li _{1 .3} for a solid electrolyte _{Ti 1 .7 Al 0 .3 (PO} 4) 3 to obtain a particulate powder.

Figure 1 is a SEM photo of _{Li 1 .3 Ti 1 .7 Al 0} .3 (PO 4) 3 powder in Example 1. The obtained.

Comparative Example  One

A mixture of 15.3 g Al (NO ₃ ) ₃ , 135.8 g TiO _2, 396.2 g NH ₄ H ₂ PO _4, and 48.0 g Li ₂ CO ₃ was prepared, and then the mixture was dried at 300 ° C. for 48 hours and then 900 After primary annealing at 2 ° C. for 2 hours and further annealing at 1100 ° C. for 2 hours, Li _1.3 Ti _1.7 Al _0.3 (PO ₄ ) ₃ powder was obtained.

Figure 2 is a SEM photo of _{Li 1 .3 Ti 1 .7 Al 0} .3 (PO 4) 3 powder obtained in the Comparative Example 1.

Example 1 and Comparative Example ₁ was Li _{1 .3} Ti obtained in _{1 .7 Al 0 .3 (PO 4} ) ₃ with respect to the powder using a LCR meter, HP4194 A measuring the ion conductivity according to the temperature, Figure 3 is the result Is a graph.

The true density of the powder particles synthesized in Example 1 is 2.35 g / cm ³ The true density of the powder particles synthesized in Comparative Example 1 is 2.13  g / cm ³ Was measured. The theoretical density of LTAP is about 2.984 g / cm ³ In the case of the true density of the powder of Example 1 prepared by the furnace sol-gel method, about 79% of the theoretical density was obtained, and the true density of the powder of Comparative Example 1 had a density value of 71%, which was synthesized by the sol-gel method. It can be seen that the density of the case is improved.

Claims (12)

A solid electrolyte comprising Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x <0.5) particles having a true density of 2.20 to 2.50 g / cm ₃ . The method of claim 1,
The solid electrolyte of the Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 _≤ x <0.5) particles having a true density of 77 to 80% by volume. The method of claim 1,
The Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x <0.5) particles are in the form of a powder. The method of claim 1,
The Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x <0.5) particles are synthesized by the sol-gel method. 5. The method of claim 4,
D50 of the primary particles synthesized by the sol-gel method is 250nm to 500nm, D90 has a particle size distribution of 350nm to 700nm. The method of claim 1,
A solid electrolyte having an ionic conductivity of 2.33 × 10 ⁻⁴ S / cm to 2.43 × 10 ⁻⁴ S / cm based on room temperature (about 25 ° C.). A negative electrode comprising a negative electrode active material;
A cathode comprising a cathode active material; And
The solid electrolyte of any one of claims 1 to 6
&Lt; / RTI &gt; Preparing a mixture by mixing a first mixed solution including a lithium raw material and a PO ₄ raw material and a second mixed solution including an alcohol, a complexing agent, and a titanium alkoxide;
Heating the mixture at 40 to 80 ° C. to form a chelate / metal sol;
Heating the sol at 200 to 300 ° C. to form a gel precursor; And
Calcining the gel precursor at 650 to 950 ° C.
Method for producing a Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x <0.5) particles for a solid electrolyte comprising a. 9. The method of claim 8,
Method for producing a Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x <0.5) particles for a solid electrolyte, wherein the first mixed solution further comprises an aluminum raw material. Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x <0.5) particles for a solid electrolyte prepared by the method of claim 8. The method of claim 10,
Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0 ≦ x <0.5) particles for solid electrolytes with a true density of 2.20 to 2.50 g / cm ₃ . The method of claim 10,
Li _{(1 + x)} Ti _(2-x) Al _x (PO ₄ ) ₃ (0≤x <0.5) particles for solid electrolytes having a true density of 77 to 80% by volume.

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