WO2015023017A1 - 이차전지용 양극 활물질 - Google Patents

이차전지용 양극 활물질 Download PDF

Info

Publication number
WO2015023017A1
WO2015023017A1 PCT/KR2013/007398 KR2013007398W WO2015023017A1 WO 2015023017 A1 WO2015023017 A1 WO 2015023017A1 KR 2013007398 W KR2013007398 W KR 2013007398W WO 2015023017 A1 WO2015023017 A1 WO 2015023017A1
Authority
WO
WIPO (PCT)
Prior art keywords
active material
sodium
secondary battery
transition metal
positive electrode
Prior art date
Application number
PCT/KR2013/007398
Other languages
English (en)
French (fr)
Inventor
김정수
김영솔
채제현
선희영
이규태
우승희
하광호
Original Assignee
에스케이이노베이션 주식회사
국립대학법인 울산과학기술대학교 산학협력단
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 에스케이이노베이션 주식회사, 국립대학법인 울산과학기술대학교 산학협력단 filed Critical 에스케이이노베이션 주식회사
Priority to US14/904,237 priority Critical patent/US10026520B2/en
Priority to PCT/KR2013/007398 priority patent/WO2015023017A1/ko
Priority to JP2016534518A priority patent/JP2016534509A/ja
Publication of WO2015023017A1 publication Critical patent/WO2015023017A1/ko

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/38—Condensed phosphates
    • C01B25/42—Pyrophosphates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a positive electrode active material for a secondary battery, and to a positive electrode active material for a secondary battery capable of inserting / removing ions very quickly in detail.
  • An phosphate-based material of an olivine structure such as LiFeP0 4 of a lithium ion battery is a material having excellent stability due to strong P-0 bonds.
  • the object of the present invention is to provide a secondary battery positive electrode active material having excellent structural stability and reversible insertion and desorption of silver.
  • the present invention provides a positive electrode active material for a secondary battery, the secondary battery according to the present invention
  • the positive electrode active material contains sodium transition metal pyrophosphate satisfying the following formula (1).
  • the sodium transition metal pyrophosphate may be a triclinic phase.
  • the sodium transition metal pyrophosphate may be a P-1 space group.
  • Ml and M2 of sodium transition metal pyrophosphate are independently of each other, Co, Ni, Fe, Mn, V, Cu, Ti, Al, Cr, It may be one or more selected elements from Mo and Nb.
  • a of the sodium transition metal pyrophosphate may be one or more selected elements from Li, Mg, and Ca.
  • the sodium transition metal pyrophosphate may contain at least iron (Fe), manganese (Mn), or iron and manganese.
  • the positive electrode active material for a secondary battery according to an embodiment of the present invention may have a capacity of 80 mAh / g or more under layer discharge conditions of 1.7 V / 4.0 V and 0.05 C.
  • the cathode active material for a secondary battery may be for a sodium secondary battery.
  • the cathode active material for a secondary battery may further contain carbon.
  • the present invention includes a sodium secondary battery containing the positive electrode active material described above.
  • the positive electrode active material for secondary batteries according to the present invention contains sodium transition metal pyrophosphate according to formula I, and has structural advantages due to the strong P-0 bond of the sodium transition metal phosphate having an oligo structure. As a result, the smooth insertion and desorption of Na ions having a large ion radius can be performed, thereby remarkably improving the reversibility and layer discharge speed during layer discharge.
  • Fig. 1 is a scanning electron micrograph of the manufactured sodium iron pyrophosphate.
  • Fig. 2 is a manufactured sodium iron pyrophosphate, iron-manganese (Fe 1 22 M n
  • FIG. 3 is a diagram illustrating a crystal structure of manufactured sodium iron pyrophosphate by Rietveld refinement using the GSAS program.
  • FIG. 6 is a diagram showing a reversible capacity according to the number of charge and discharge cycles of a manufactured sodium iron pyrophosphate secondary battery
  • FIG. 7 is a diagram showing changes in reversible capacity (speed characteristic) according to an increase in current density of a manufactured sodium iron pyrophosphate secondary battery.
  • the cathode active material for a secondary battery according to the present invention contains sodium transition metal pyrophosphate satisfying the following formula (1).
  • M 2 may be the same element having different atoms, and may be different elements having different atoms. May be one or more elements with the atoms of a, and M 2 may be one or more elements with the atoms of b.
  • A may be selected from one or more of alkali metals and alkaline earth metals except sodium (Na).
  • M or M 2 is At least it may contain transition metals.
  • a cathode active material for a secondary battery according to an embodiment of the present invention wherein the transition metal is Sc, Ti,
  • Groups 12 to 14 may include Zn, Al, Ga, In, Tl, Ge, Sn and Pb groups.
  • the alkali metal may include Li, K, Rb, and Cs groups
  • the alkaline earth metal may include Be, Mg, Ca, Sr, and Ba groups. have.
  • sodium transition metal pyrophosphate of Chemical Formula 1 may be a discharge state composition of the positive electrode active material.
  • a layer discharge is performed at 0.05C in the Na / Na + voltage range, it can mean that the discharge is completed at 1.7 V, and may include the discharge state of the first charge-discharge cycle (charge-discharge).
  • the sodium secondary battery subjected to the cycle is
  • Cathodic active Conductive material: Binder is mixed in a weight ratio of 7: 1.5: 1.5 and N-methyl
  • a slurry of the positive electrode active material prepared by injecting pyrrolidone (NMP) solution was applied on an aluminum foil, and dried in a vacuum oven at 120 ° C. for 10 hours to prepare a positive electrode and sodium metal as a counter electrode, 0.8 M NaC10 4
  • sodium transition metals such as NaFeP0 4 in the cathode active material for sodium secondary batteries
  • the sodium transition metal phosphate has an oligo structure, so that when the ion radius is very large, such as Na ions, structural limitations are unlikely to result in reversible insertion and removal of ions.
  • the sodium transition metal phosphate having an oligo structure is used as the positive electrode active material of the secondary battery, not only the reversibility of the reaction but also the layer discharge rate is very low.
  • the positive electrode active material for sodium secondary battery according to the present invention contains sodium transition metal pyrophosphate of Formula 1, and has a strong structural stability even when inserting and desorbing ions due to strong P-0 bonds. Smooth insertion and desorption of ions with large ionic radii can be performed to significantly improve reversibility and layer discharge rates during charging and discharging.
  • the sodium transition metal pyrophosphate may be a triclinic phase, and may have a crystal structure of ⁇ -1 space group. Transition metal pyrophosphates [100] and [010] Sodium in the direction can have a tunnel structure with a smooth movement of (Na + ).
  • a contained in sodium transition metal pyrophosphate may be one or more selected elements from Li, Mg, and Ca.
  • Li, Mg, and Ca have an ion radius similar to that of Na, which can be substituted for the site of sodium (sodium ions) in the crystal structure of sodium transition metal pyrophosphate, leading to a substitutional solid solution. .
  • M, and M 2 contained in sodium transition metal pyrophosphate according to Formula 1 are independently of each other, Co, Ni, Fe, Mn, V, It may be at least one selected from Cu, Ti, Al, Cr, Mo and Nb.
  • the transition metals Ml and M2 contained in the sodium transition metal pyrophosphate according to Formula 1 may be different elements.
  • M L and M 2 contained in sodium transition metal pyrophosphate according to Formula 1 are independently of each other, but at least in Co, Ni, Fe, and Mn. Alternatively, more than one may be selected, preferably, different elements from and M 2 fe.
  • the cathode active material for a secondary battery may contain sodium transition metal pyrophosphate satisfying the following Formula 1-1.
  • ⁇ 3 ⁇ is one or more selected from Co, Ni, Fe, Mn, V, Cu, Ti, Al, Cr, Mo and Nb having a valency of 2 (M 3 )
  • Co, Ni, Fe, Mn, V, Cu, Ti, Al, Cr, Mo, and Nb have similar ionic radii, so that the transition metals in the crystal structure of sodium transition metal pyrophosphates (eg, Fe C) can be substituted at the site, leading to a substitutional solid solution.
  • transition metal pyrophosphates eg, Fe C
  • the cathode active material 3 ⁇ 4 for secondary batteries is represented by the following chemical formula
  • It may contain sodium transition metal pyrophosphate that satisfies 1-2.
  • ⁇ 5 ⁇ is an element (M 5 ) at least one selected from Co, Mn, Ni, and Fe having a valency of 2.
  • the positive electrode active material for secondary batteries may contain particulate sodium transition metal pyrophosphate.
  • the positive electrode active material for secondary batteries has a particulate sodium transition having an average primary particle size of 500 nm to ⁇ . It can contain metal pyrophosphate.
  • the positive electrode active material for secondary batteries consists of primary particles and may contain sodium transition metal pyrophosphate, a secondary particle having an average size of ⁇ to 500 ⁇ .
  • the positive electrode active material for a secondary battery according to one embodiment of the present invention may further contain carbon. Carbon contained in the positive electrode active material is sufficient to satisfy carbon used in a normal secondary battery positive electrode active material, for example, acetylene black, By all means, soft or hard carbon.
  • the sodium transition metal pyrophosphate contained in the positive electrode active material is in a particulate form, and a coating layer coated with carbon may be formed on the surface of the particle.
  • the positive electrode active material may further contain 1 to 43 parts by weight of carbon based on 100 parts by weight of sodium transition metal pyrophosphate. Carbon may be in a homogeneous mixture with sodium transition metal pyrophosphate and may exist as a coating layer on the surface of the sodium transition metal pyrophosphate particles.
  • the positive electrode active material for a secondary battery is 1.7 / 4.0 V and 0.05 to 0.05.
  • It can have a capacity of more than 80mAh / g under charge and discharge conditions of 0.2C (current density).
  • the cathode active material for a secondary battery may be a cathode active material for a sodium secondary battery.
  • the sodium secondary battery may be a sodium secondary battery or an all-solid-state Na secondary battery having molten Na as a cathode.
  • the present invention includes a cathode for a sodium secondary battery containing the cathode active material for secondary batteries described above.
  • the anode may include the cathode active material and the current collector described above, and a cathode active material layer coated or coated with the cathode active material may be formed on at least one surface of the current collector.
  • a slurry of the positive electrode active material may be applied or coated on the current collector, and the positive electrode active material slurry may contain a dispersion medium, a binder, and a conductive agent commonly used in the manufacture of the secondary battery active material together with the positive electrode active material described above.
  • the present invention includes the above-described anode secondary sodium battery.
  • a sodium secondary battery may include a cathode containing sodium, an anode having the above-described cathode active material, and an electrolyte having an ion conductivity with respect to sodium ions, provided between the anode and the cathode.
  • the sodium secondary battery according to one embodiment of the present invention is an all-solid sodium, in which both the negative electrode containing sodium, the positive electrode containing the positive electrode active material described above, and the electrolyte are all solid.
  • a secondary battery including a sodium secondary battery with a liquid electrolyte, a sodium secondary battery with a positive electrolyte along with a solid electrolyte (for example, NASICON), and a separator may be further provided if necessary.
  • electrolyte or liquid electrolyte
  • the anode and / or cathode may be located in the electrolyte so that the sodium ions conducted in the solid electrolyte can be effectively transferred to the active material.
  • the cathode is sodium
  • the electrolyte may include an organic solvent containing sodium salt.
  • the cathode may be a sodium metal
  • the sodium salt in the electrolyte may be NaAsF 6 , NaPF 6 , NaC 10 4 , NaB. (C 6 H 5 ), NaAlCl 4 , NaBr, NaBF 4 or a combination thereof.
  • the organic solvent may be ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate. (methylethyl carbonate), propylene carbonate or their mixtures, although the present invention cannot be limited by the type of cathode, the type of electrolyte or the structure of the battery.
  • the manufacturing method includes the steps of: preparing a precursor raw material by mixing a sodium precursor, a metal precursor and a phosphate precursor; b) heat treating the precursor raw material in an inert gas atmosphere.
  • step b) comprises the steps of bl) heat treating the precursor material in an inert gas atmosphere of 200 to 400 ° C. to produce a first precursor material; and b2) pulverizing the first precursor material; b3) 500 to 1 milled precursor material
  • the grinding step (b4) of physically crushing to have a size suitable for the positive electrode active material can be further performed.
  • the sodium precursor is sodium carbonate (Na 2 CO 3 ), sodium acetate (NaOCH 2 CH 3 ), sodium carbonate (Na 2 CO 3 ) May include one or more selected materials from sodium hydroxide (NaOH) and their hydrates.
  • the metal precursor may comprise one or more selected materials from oxalates, acetates, carbonates and their hydrates of the metal.
  • the precursor may comprise one or more materials selected from (NH 4 ) 2 HP0 4 , NH 4 H 2 P0 4 , and 3 ⁇ 41> 4 .
  • the metal of the metal precursor may be one or more selected elements from transition metal and group 12 to 14, Specifically, the transition metal is Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Tc, Ru, Th, Pd, Ag, Hf, Ta, W, Re, Os, Ir,
  • Group Pt and Au, group 12 to 14 are Zn, Al, Ga, In, Tl, Ge, Sn and
  • the metals in the metal precursors are Co, Ni, Fe, Mn, V, Cu,
  • the metal of the metal precursor may be at least one element selected from Co, Ni, Fe and Mn.
  • each precursor material can be mixed so that the molar ratio of Na: metal: phosphoric acid is 3 to 3.3: 2.2 to 2.5: 1 in the production of precursor raw materials.
  • the mixing of the precursors can be carried out by milling, which is typically used for the homogeneous mixing and grinding of powders, such as ball mills, rod mills or attrition mills. It can be done using the method.
  • the raw materials produced are heat treated in an inert gas atmosphere comprising argon, helium, neon, nitrogen or their mixtures.
  • the manufactured raw material is subjected to low temperature heat treatment at a temperature of 200 to 400 ° C. in an inert gas atmosphere, and then pulverizes the product obtained by the low temperature heat treatment to a temperature of 500 to 700 ° C. in an inert gas atmosphere. It can be hot heat treated.
  • low and high temperature two-stage heat treatment of precursor raw materials are carried out, and the product obtained by low temperature heat treatment is again crushed and mixed by milling including ball mill, rod mill or attrition mill.
  • milling including ball mill, rod mill or attrition mill.
  • Pyrophosphate Conductive material (Carbon black (super P)): Binder (PVdF; Polyvinylidene fluoride) was mixed in a weight ratio of 7: 1.5: 1.5, and a slurry was prepared using N-methylpyrrolidone (NMP) solution. The slurry was then applied over aluminum foil and dried in a vacuum furnace at 120 ° C. for 10 hours to produce an anode. The anode was prepared in a globe box with sodium metal as the counter electrode, containing 0.8 M NaClO 4 . Ethylene carbonate / diethylene carbonate (l / 1 vol. Ratio) was used as an electrolyte to prepare a cell.
  • NMP N-methylpyrrolidone
  • FIG. 1 is a scanning electron micrograph of the sodium iron pyrophosphate prepared in Preparation Example 1
  • Figure 1 (a) is a high magnification scanning electron micrograph
  • Figure 1 (b) is a low magnification
  • FIG. 1 A view showing an X- ray diffraction analysis results, and FIG.
  • Na 3.12 Fe 2 .44 (P 2 0 7) 2 prepared in Preparation Example 2 1 triclinic crystal system of Na ⁇ Fe ⁇ Mn ⁇ X ⁇ O ⁇ and Production Example '3 confirm that ⁇ .12 ⁇ 2.44 ( ⁇ 2 0 7 ) 2 was prepared.
  • the prepared sodium transition metal pyrophosphate has a P-1 space group, and as shown in FIG. It can be seen that the ion radius provides a pathway for desorption of large sodium ions.
  • FIG. 6 is a view showing the reversible capacity according to the number of charge and discharge cycles of a sodium secondary battery of Preparation Example 4 containing sodium iron pyrophosphate prepared in Preparation Example 1 as a cathode active material, and 1.7 (discharge)- 4.0 (layer war) V vs. Results of layer discharge at 0.05 C (C / 20 in FIG. 6) and 0.2 C (C / 5 in FIG. 6) in the Na / Na + voltage range. As can be seen in FIG. 6, the reversible insertion and desorption of sodium silver It can be seen that it is performed smoothly, and it can be seen that it has stable layer discharge characteristics even up to 60 cycles.
  • the reversible capacity is SOmAhg- 1 or higher, and a reversible capacity of 65 ⁇ 1 ⁇ ⁇ or more is maintained even at a current density of 1C (1C in FIG. 6).
  • FIG. 8 is a diagram illustrating the crystal structure of the layered sodium iron pyrophosphate using Rietveld refinement using the GSAS program to confirm the structural change.
  • FIG. 9 is a rietveld refinement of the positive electrode active material in the charged state of FIG. As can be seen from the crystal structure analysis, it was confirmed that the tetraclinic structure was maintained even when the sodium ion was inserted or removed.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

본 발명은 이차전지용 양극 활물질에 관한 것으로, 상세하게, 본 발명에 따른 이차전지용 양극 활물질은 Na3.12-x2Ac x1M1 a y1M2 b y2(P2O7)2을 만족하는 나트륨 전이금속 피로인산염을 함유하며, 올리빈 구조의 나트륨 전이금속 인산염이 갖는 강한 P-O 결합에 따른 구조적 안정성의 장점을 가지면서도, 이온 반경이 큰 Na 이온의 원활한 삽입 및 탈리가 수행되어 충방전시의 가역성 및 충방전 속도를 현저하게 향상시킬수 있는 장점이 있다.

Description

명세서
발명의명칭:이차전지용양극활물질 기술분야
[1] 본발명은이차전지용양극활물질에관한것으로，상세하게구조내매우빠른 이온의삽입 /탈리가가능한이차전지용양극활물질에관한것이다.
배경기술
[2] 리튬이온전지의 LiFeP04와같은올리빈구조의포스페이트 (phosphate)계열 소재는상용화된양극소재증의하나로써강한 P-0결합으로인해서매우 안정성이우수한소재이다.
[3] 따라서나트륨이차전지에서도이러한유사한구조의소재를양극소재로
이용하고자하는노력이있어왔다.최근들어미국공개공보제 20110008233호와 같이 NaMP04(M=Fe,Co,Ni,Mn)와같은올리빈포스페이트소재를나트륨 이차전지에활용하고자하는기술적접근이이뤄지고있다.그러나，나트륨 이온은리튬이온크기보다훨씬큰이온크기를가짐에따라，이온의크기에 의해 Na이온의가역적인삽입 /탈리가원활하지않아동적특성 (kinetic 측면)에서문제가많기때문에，아직만족스러운전지성능올보이지않고있다. 따라서기존의 NaFeP04계소재보다훨씬더우수한동적특성을갖는새로운 소재의개발이필요한실정이다.
발명의상세한설명
기술적과제
[4] 본발명의목적은구조적안정성이우수하면서도가역적인이은의삽입및 탈리가극히원활히발생하는이차전지용양극활물질및이를구비한
이차전지를제공하는것이다.
과제해결수단
[5] 본발명은이차전지용양극활물질을제공하며，본발명에따른이차전지용
양극활물질은하기화학식 1을만족하는나트륨전이금속피로인산염을 함유한다.
[6] (화학식 1)
[7] Na3.12.x2Ac xlM1 a ylM2>'y2(P207)2
[8] 화학식 I에서 Ac는 1또는 2인 c의원자가를갖는알칼리금속및알칼리
토금속에서하나또는둘이상선택된원소 (A)를의미하며, xl는 0≤xl≤0.5인 실수이고， x2는 c와 xl의곱 (x2 = x l * c)이며， M,a는 a의원자가를갖는전이금속 및 12내지 14족에서하나또는둘이상선택된원소 (M0를의미하고， M2 b는 b의 원자가를갖는전이금속및 12내지 14족에서하나또는둘이상선택된원소 (M2 )를의미하며， a와 b는서로같거나상이하며 , a와 b는서로독립적으로 2내지 4의정수이며， yl은 0<yl≤2.44인실수이고， y2는 0≤y2≤2.44인실수이다. [9] 본발명의일실시예에따른이차전지용양극활물질에있어,나트륨전이금속 피로인산염은삼사정계 (Triclinic phase)일수있다.
[10] 본발명의일실시예에따른이차전지용양극활물질에있어，나트륨전이금속 피로인산염은 P-1공간군 (space group)일수있다.
[Π] 본발명의일실시예에따른이차전지용양극활물질에있어，나트륨전이금속 피로인산염은화학식 1에서 ^1 * 3) + ^2 * 1)) = 4.88을만족할수있다.
[12] 본발명의일실시예에따른이차전지용양극활물질에있어，나트륨전이금속 피로인산염의 Ml및 M2는서로독립적으로， Co, Ni, Fe, Mn, V, Cu, Ti, Al, Cr, Mo 및 Nb에서하나또는둘이상선택된원소일수있다.
[13] 본발명의일실시예에따른이차전지용양극활물질에있어，나트름전이금속 피로인산염의 A는 Li, Mg및 Ca에서하나또는둘이상선택된원소일수있다.
[14] 본발명의일실시예에따른이차전지용양극활물질에있어，나트륨전이금속 피로인산염은적어도철 (Fe),망간 (Mn)또는철과망간을함유할수있다.
[15] 본발명의일실시예에따른이차전지용양극활물질은 1.7V/4.0V및 0.05C의 층방전조건에서 80mAh/g이상의용량을가질수있다ᅳ
[16] 본발명의일실시예에따른이차전지용양극활물질은나트륨이차전지용일수 있다.
[17] 본발명의일실시예에따른이차전지용양극활물질은탄소를더함유할수 있다.
[18] 본발명은상술한양극활물질을포함하는나트륨이차전지를포함한다.
발명의효과
[19] 본발명에따른이차전지용양극활물질은화학식 I에따른나트륨전이금속 피로인산염을함유함에따라，올리빈구조의나트륨전이금속인산염이갖는 강한 P-0결합에따른구조적안정성의장점을가지면서도,이온반경이큰 Na 이온의원활한삽입및탈리가수행되어층방전시의가역성및층방전속도를 현저하게향상시킬수있다.
도면의간단한설명
[20] 도 1은제조된나트륨철피로인산염을관찰한주사전자현미경사진이며， [21] 도 2는제조된나트륨철피로인산염，철 -망간 (Fe1 22Mn|.22)피로산염，망간
피로산염의 X-선회절분석결과를도시한도면이며,
[22] 도 3은제조된나트륨철피로인산염을 GSAS프로그램을사용하여 Rietveld refinement통해결정구조를분석한도면이며，
[23] 도 4는제조된나트륨철피로인산염의결정구조를도시한모식도이며,
[24] 도 5는제조된나트륨철피로인산염이차전지의층방전특성을도시한
도면이며,
[25] 도 6는제조된나트륨철피로인산염이차전지의충방전싸이클흿수에따른 가역용량을도시한도면이며， [26] 도 7은제조된나트륨철피로인산염이차전지의전류밀도의증가에따른가역 용량의변화 (속도특성)를도시한도면이며，
[27] 도 8은제조된나트륨철피로인산염을층전상태의나트륨철피로인산염을
GSAS프로그램을사용하여 Rietveld refinement통해결정구조를분석한 도면이다.
[28]
발명의실시를위한형태
[29] 이하본발명에따른양극활물질을상세히설명한다.이때，사용되는기술용어 및과학용어에있어서다른정의가없다면,이발명이속하는기술분야에서 통상의지식을가진자가통상적으로이해하고있는의미를가지며，하기의설명 및첨부도면에서본발명의요지를불필요하게흐릴수있는공지기능및 구성에대한설명은생략한다.
[30] 본발명에따른이차전지용양극활물질은하기화학식 1을만족하는나트륨 전이금속피로인산염 (Na Transition Metal Pyrophosphate)을함유한다.
[31] (화학식 1)
[32] Na3,2.X2Ac x,M1%,M2"y2(P207)2
[33] 화학식 1에서 는 1또는 2인 c의원자가를갖는알칼리금속및알칼리
토금속에서하나또는둘이상선택된원소 (A)를의미하며， xl는 0≤xl≤0.5인 실수이고， x2는 c와 xl의곱 (x2 = xl * c)이며, M,a는 a의원자가를갖는전이금속 및 12내지 14족에서하나또는둘이상선택된원소 (M 를의미하고， 는 b의 원자가를갖는전이금속및 12내지 14족에서하나또는둘이상선택된원소 (M2 )를의미하며， a와 b는서로같거나상이하며 , a와 b는서로독립적으로 2내지 4의정수이며， yl은 0<yl≤2.44인실수이고, y2는 0≤y2≤2.44인실수이다.
[34] 이하，화학식을상술함에있어 , A, 또는 ^I2와같이원자가 (a, b, c)를병기하지 않은경우，원자가를제외한기호 (A, M,또는 M2)는화학식 1에따른화합물에 함유되는원소를의미하며， ^, ^^ 와같이원자가를같이병기하는경우, 원자가를포함한기호 (Α<=,ΜΛΜ )는화학식 1에따른화합물구조내에서각 원소의해당원자가의이은상태，즉, +c, +a, +b가의원소이온을지칭할수있다.
[35] 본발명의일실시예에따른이차전지용양극활물질에있어,화학식 1에서， 및 M2는서로다른원자가를갖는동일한원소일수있으며，서로다른원자가를 갖는서로다른원소일수있다.또한, ^은 a의원자가를갖는,하나또는둘 이상의원소일수있으며， M2는 b의원자가를갖는，하나또는둘이상의원소일 수있다.
[36] 본발명의일실시예에따른이차전지용양극활물질에있어，화학식 1에서 , A는 나트륨 (Na)를제외한알칼리금속및알칼리토금속에서하나또는둘이상 선택된것일수있다.
[37] 본발명의일실시예에따른이차전지용양극활물질에있어， M,또는 M2는 적어도전이금속을함유할수있다.
[38] 본발명의일실시예에따른이차전지용양극활물질에있어,화학식 1에따른 나트륨전이금속피로인산염은 (yl * a) + (y2 * b) = 4.88을만족할수있다.
[39] 본발명의일실시예에따른이차전지용양극활물질에있어，전이금속은 Sc, Ti,
V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Tc, Ru, Th, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt 및 Au군을포함할수있으며， 12내지 14족은 Zn, Al, Ga, In, Tl, Ge, Sn및 Pb군을 포함할수있다.
[40] 본발명의일실시예에따른이차전지용양극활물질에있어，알칼리금속은 Li, K, Rb및 Cs군을포함할수있으며，알칼리토금속은 Be, Mg, Ca, Sr및 Ba군을 포함할수있다.
[41] 본발명의일실시예에따른이차전지용양극활물질에있어,화학식 1의나트륨 전이금속피로인산염 (Na Transition Metal Pyrophosphate)은양극활물질의 방전상태조성일수있다.이때，방전상태는양극활물질을함유하는양극이 구비된나트륨이차전지를 1 /7(방전 )~4.0V (층전) vs. Na/Na+전압범위에서 0.05C로층방전을수행할때 1.7V로방전이완료된상태를의미할수있으며， 첫번째충방전싸이클 (충전-방전의순)의방전상태를포함할수있다.상세하게, 층방전싸이클이수행되는나트륨이차전지는본발명에따른
양극활을질:도전재：바인더를 7: 1.5: 1.5의중량비로흔합하고 N-메틸
피롤리돈 (NMP)용액을투입하여제조된양극활물질슬러리를알루미늄포일 위에도포하고， 120°C진공오본에서 10시간동안건조하여제조된양극및 나트륨메탈을반대전극으로, 0.8M NaC104
/(ethylenecarbonate+diethylenecarbonate, 1： 1 vol.ratio)^:전해질로시"용한전 ;지를 포함할수있다.
[42] 나트륨이차전지용양극활물질에 NaFeP04와같은나트륨전이금속
인산염 (phosphate)을사용하고자하는시도가있어왔으나,나트륨전이금속 인산염은올리빈구조를가짐에따라， Na이온과같이이온반경이매우큰경우， 이온의가역적인삽입및탈리가원활하지않는구조적한계를가진다.이에 따라，올리빈구조의나트륨전이금속인산염을이차전지의양극활물질로 사용하는경우，반웅의가역성뿐만아니라，층방전속도가매우떨어지는 문제점이있다.
[43] 본발명에따른나트륨이차전지용양극활물질은화학식 1의나트륨전이금속 피로인산염을함유함에따라강한 P-0결합에따른이온의삽입및탈리시에도 견고한구조적안정성을가지면서도， Na이온과같이이온반경이큰이온의 원활한삽입및탈리가수행되어충방전시의가역성및층방전속도를현저하게 향상시킬수있다.
[44] 본발명의일실시예에따른이차전지용양극활물질에있어，나트륨전이금속 피로인산염은삼사정계 (Triclinic phase)일수있으며 , Ρ-1공간군의결정구조를 가질수있다.이러한구조에의해나트륨전이금속피로인산염은 [100]및 [010] 방향으로나트륨이은 (Na+)의원활한이동이이루어지는터널구조를가질수 있다.
[45] 본발명의일실시예에따른이차전지용양극활물질에있어，나트륨전이금속 피로인산염에함유되는 A는 Li, Mg및 Ca에서하나또는둘이상선택된원소일 수있다. Li, Mg및 Ca는 Na와유사한이온반경을가져 ,나트륨전이금속 피로인산염의결정구조에서나트륨 (나트륨이온)의자리 (site)에치환될수 있으며,치환형고용체 (substitutional solid solution)을이를수있다.
[46] 본발명의일실시예에따른이차전지용양극활물질에있어,화학식 1에따른 나트륨전이금속피로인산염에함유되는 M,및 M2는서로독립적으로， Co, Ni, Fe, Mn, V, Cu, Ti, Al, Cr, Mo및 Nb에서적어도하나이상선택된것일수있다. 바람직하게，화학식 1에따른나트륨전이금속피로인산염에함유되는 전이금속인 Ml및 M2는서로상이한원소일수있다.
[47] 본발명의일실시예에따른이차전지용양극활물질에있어，화학식 1에따른 나트륨전이금속피로인산염에함유되는 ML및 M2는서로독립적으로， Co, Ni, Fe 및 Mn에서적어도하나또는둘이상선택된것일수있으며 ,바람직하게， 과 M2fe서로상이한원소일수있다.
[48] 구체적으로본발명의일실시예에따른이차전지용양극활물질은하기화학식 1-1을만족하는나트륨전이금속피로인산염을함유할수있다.
[49] (화학식 1-1) ,
[5이 Na3.12M3 44-y5M4 b y4(P207)2
[51] 화학식 1-1에서， Μ3 Π는 2의원자가를갖는 Co, Ni, Fe, Mn, V, Cu, Ti, Al, Cr, Mo 및 Nb에서하나또는둘이상선택된원소 (M3)이며， M4 b는 b의원자가를갖는 Co, Ni, Fe, Mn, V, Cu, Ti, Al, Cr, Mo및 Nb에서하나또는들이상선택된원소 (M4 )이며, b는 3또는 4의정수이며， y5 = y4 * b이며， y5은 0≤y5≤2.44인실수이다.
[52] Co, Ni, Fe, Mn, V, Cu, Ti, Al, Cr, Mo및 Nb는서로유사한이온반경을가짐에 따라，나트륨전이금속피로인산염의결정구조에서전이금속 (일예로， Fe)의 자리 (site)에치환될수있으며,치환형고용체 (substitutional solid solution)을이를 수있다.
[53] 구체적으로본발명의일실시예에따른이차전지용양극활물¾은하기화학식
1-2을만족하는나트륨전이금속피로인산염을함유할수있다.
[54] (화학식 1-2)
[55] Na3.12M5n2.44(P207)2
[56] 화학식 1-2에서 , Μ5 Π는 2의원자가를갖는 Co, Mn, Ni및 Fe에서하나또는둘 이상선택된원소 (M5)이다.
[57] Co, Mn, Ni및 Fe는모두전기화학적으로산화환원반웅가능함에따라층전 및방전반웅에관여할수있으며，서로유사한이온반경을가짐에따라,나트륨 전이금속피로인산염의결정구조에서전이금속 (일예로， Fe)의자리 (site)에 치환될수있으며，치환형고용체 (substitutional solid solution)을이를수있다. [58] 본발명의일실시예에따른이차전지용양극활물질은입자상의나트륨 전이금속피로인산염을함유할수있다.상세하게，이차전지용양극활물질은 500nm내지 ΙΟμπι의평균 1차입자크기를갖는입자상의나트륨전이금속 피로인산염을함유할수있다.상세하게，이차전지용양극활물질은 1차 입자들로이루어지며 ΙΟμιη내지 500μπι평균크기를갖는 2차입자인나트륨 전이금속피로인산염을함유할수있다.
[59] 본발명의일실시예에따른이차전지용양극활물질은탄소를더함유할수 있다.양극활물질에함유되는탄소는통상의이차전지양극활물질에사용되는 탄소이면족하며,일예로，아세틸렌블랙，혹연，소프트카본또는하드카본을들 수있다.
[60] 본발명의일실시예에따른이차전지용양극활물질에있어，양극활물질에 함유되는나트륨전이금속피로인산염은입자상이며，입자표면에탄소가 코팅된코팅층이형성될수있다.
[61] 본발명의일실시예에따른이차전지용양극활물질에있어，양극활물질은 나트륨전이금속피로인산염 100중량부를기준으로 1내지 43중량부의탄소를 더함유할수있다.이때，양극활물질에함유되는탄소는나트륨전이금속 피로인산염과균질하게흔합된상태일수있으며，나트륨전이금속피로인산염 입자의표면에코팅된코팅층으로존재할수있다.
[62] 본발명의일실시예에따른이차전지용양극활물질은 1.7/4.0V및 0.05내지
0.2C (전류밀도)의충방전조건에서 80mAh/g이상의용량을가질수있다.
[63] 본발명의일실시예에따른이차전지용양극활물질은나트륨이차전지용 양극활물질일수있다.이때，나트륨이차전지는용융 Na를음극으로갖는 나트륨이차전지또는전고체형 Na이차전지일수있다.
[64] 본발명은상술한이차전지용양극활물질을포함하는나트륨이차전지용 양극을포함한다.
[65] 본발명의일실시예에따른양극은상술한양극활물질및집전체를포함할수 있으며，집전체의적어도일면에양극활물질이도포또는코팅된양극 활물질층이형성될수있다.상세하게，양극활물질층을형성하기위해, 집전체에양극활물질슬러리가도포또는코팅될수있으며，양극활물질 슬러리는상술한양극활물질과함께이차전지활물질제조에통상적으로 사용되는분산매,바인더및도전제를함유할수있다.
[66] 본발명은상술한양극이구비된나트륨이차전지를포함한다.
[67] 본발명의일실시예에따른나트륨이차전지는나트륨을함유하는음극， 상술한양극활물질이구비된양극및양극과음극사이에구비되며나트륨 이온에대해이온전도도를갖는전해질을포함할수있다.
[68]
[69] 본발명의일실시예에따른나트륨이차전지는나트륨을함유하는음극, 상술한양극활물질을함유하는양극및전해질이모두고체인전고체형나트륨 이차전지를포함하며,액상의전해질이구비되는나트륨이차전지를포함하며， 고체형전해질 (일예로， NASICON)과함께양극전해액이구비되는나트륨 이차전지를포함하며,필요시분리막이더구비될수있다.전해액 (또는 액상전해질)이구비되는경우,고체전해질에서전도된나트륨이온이활물질에 효과적으로전달될수있도록，양극및 /또는음극은전해액내에위치할수있다.
[70] 본발명의일실시예에따른나트륨이차전지에있어，음극은나트륨을
함유하는음극활물질을포함하며，전해질은나트륨염을함유하는유기용매를 포함할수있다.실질적인일예로，음극은나트륨금속일수있으며，전해질에 함유되는나트륨염은 NaAsF6,NaPF6,NaC104,NaB(C6H5),NaAlCl4,NaBr,NaBF4또는 이들의흔합물을포함할수있으며,유기용매는에틸렌카르보네이트 (ethylene carbonate),디메틸카르보네이트 (dimethyl carbonate),메틸에틸카르보네이트 (methylethyl carbonate),프로필렌카르보네이트 (propylene carbonate)또는이들의 흔합물을함유할수있으나，본발명이음극의종류，전해질의종류또는전지의 구조에의해한정될수없음은물론이다.
[71] 이하，이차전지양극활물질용나트륨전이금속피로인산염의제조방법에대해 상술한다.
[72] 본발명에따른이차전지양극활물질용나트륨전이금속피로인산염의
제조방법은 a)나트륨전구체，금속전구체및인산전구체를흔합하여전구체 원료를제조하는단계; b)전구체원료를불활성기체분위기에서열처리하는 단계;를포함하여수행된다.
[73] 본발명의일실시예에따른이차전지양극활물질용나트륨전이금속
피로인산염의제조방법에있어， b)단계는 bl)전구체원료를 200내지 400oC의 불활성기체분위기에서열처리하여제 1전구체원료를제조하는단계;및 b2) 제 1전구체원료를분쇄하는단계; b3)분쇄된제 1전구체원료를 500내지
700°C의불활성기체분위기에서열처리하여나트륨전이금속피로인산염을 제조하는단계;를포함할수있다.이때， b3)단계에서수득된산물을
양극활물질에적합한크기를갖도록물리적으로파쇄하는분쇄단계 (b4)가더 수행될수있음은물론이다.
[74] 본발명의일실시예에따른나트륨이차전지양극활물질용나트륨전이금속 피로인산염의제조방법에있어，나트륨전구체는탄산나트륨 (Na2C03),나트륨 아세테이트 (NaOCH2CH3),나트륨카보네이트 (Na2C03),수산화나트륨 (NaOH) 및이들의수화물에서하나또는둘이상선택된물질을포함할수있다.금속 전구체는금속의옥살산염,아세테이트,카보네이트및이들의수화물에서하나 또는둘이상선택된물질을포함할수있다.인산전구체는 (NH4)2HP04,NH4H2 P04,및 ¾1>ᄋ4에서하나또는둘이상선택된물질을포함할수있다.
[75] 본발명의일실시예에따른나트륨이차전지양극활물질용나트륨전이금속 피로인산염의제조방법에있어，금속전구체의금속은전이금속및 12내지 14족에서하나또는둘이상선택된원소일수있으며,상세하게，전이금속은 Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Tc, Ru, Th, Pd, Ag, Hf, Ta, W, Re, Os, Ir,
Pt및 Au군을포함할수있으며， 12내지 14족은 Zn, Al, Ga, In, Tl, Ge, Sn및
Pb군을포함할수있다.바람직하게,금속전구체의금속은 Co, Ni, Fe, Mn, V, Cu,
Ti, Al, Cr, Mo및 Nb에서적어도하나이상선택된원소일수있다.보다 상세하게，금속전구체의금속은 Co, Ni, Fe및 Mn에서적어도하나이상선택된 것일수있다.
[76] 본발명의일실시예에따른이차전지양극활물질용나트륨전이금속
피로인산염의제조방법에있어,전구체원료의제조시, Na :금속：인산이 3내지 3.3： 2.2내지 2.5： 1의몰비가되도록각전구체물질이흔합될수있다.
[77] 본발명의일실시예에따른이차전지양극활물질용나트륨전이금속
피로인산염의제조방법에있어,전구체원료의제조시，전구체들의흔합은 밀링에의해수행될수있으며，이러한밀링은볼밀,로드밀또는어트리션밀과 같이파우더들의균질한흔합및분쇄에사용되는통상적으로방법을이용하여 수행될수있다.
[78] 본발명의일실시예에따른이차전지양극활물질용나트륨전이금속
피로인산염의제조방법에있어，제조된원료는아르곤,헬륨，네온，질소또는 이들의흔합기체를포함하는불활성기체분위기에서열처리된다.
[79] 상세하게 ,제조된원료는불활성기체분위기에서 200내지 400°C의온도로 저온열처리된후，저온열처리에의해수득된생성물을분쇄하여다시불활성 기체분위기에서 500내지 700°C의온도로고온열처리될수있다.
[80] 본발명의일실시예에따른이차전지양극활물질용나트륨전이금속
피로인산염의제조방법에있어，전구체원료에대해저온및고온의 2단 열처리를수행하고,저온열처리에의해수득된생성물을볼밀，로드밀또는 어트리션밀을포함하는밀링을통해다시분쇄및흔합한후고온열처리를 수행함으로써,조성적균일성이우수하고，마이크로미터오더의 1차입자 크기를갖는나트륨전이금속피로인산염을제조할수있다.
[81]
[82] 이하실제조예를통해본발명을구체적으로설명하지만，이러한실시예는본 발명을좀더명확하게이해하기위하여제시하는것일뿐，본발명의범위를 제한하는목적으로제시하는것은아니며，본발명은후술하는특허청구범위의 기술적사상의범위내에서정해질것이다.
[83]
[84] (제조예 1)
[85] 나트륨철피로인산염의제조
[86] 1.06g Na2C03, 1.8g FeC204-2H20및 2.64g (NH4)2HP04을흔합하여볼밀링한후， 이를 300°C에서 6시간동안아르곤가스분위기에서열처리 (1차)하였다. 1차 열처리된원료에대해볼밀링을수행하여다시섞은후 600°C에서 6시간동안 아르곤가스분위기에서다시열처리 (2차)하여，나트륨철피로인산염을 제조하였다.
[87] (제조예 2)
[88] 나트륨망간철피로인산염의제조
[89] 1.06g Na2C03, 0.9g FeC204-2H20, 0.9g MnC204 2H20및 2.64g (NH4)2HP04을
흔합하여볼밀링한후,이를 300°C에서 6시간동안아르곤가스분위기에서 열처리 (1차)하였다 . 1차열처리된원료에대해볼밀링을수행하여다시섞은후 600°C에서 6시간동안아르곤가스분위기에서다시열처리 (2차)하여,나트륨 망간철피로인산염을제조하였다.
[90] (제조예 3)
[91] 나트륨망간피로인산염의제조
[92] 1.06g Na2C03, 1.8g MnC204-2H20및 2.64g (NH4)2HP04을흔합하여볼밀링한후, 이를 300°C에서 6시간동안아르곤가스분위기에서열처리 (1차)하였다. 1차 열처리된원료에대해볼밀링을수행하여다시섞은후 600°C에서 6시간동안 아르곤가스분위기에서다시열처리 (2차)하여,나트륨망간피로인산염올 제조하였다.
[93] (제조예 4)
[94] 나트륨이차전지의제조
[95] 제조예 1,제조예 2또는제조예 3에서제조한나트륨전이금속
피로인산염 :도전재 (카본블랙 (super P)):바인더 (PVdF; Polyvinylidene fluoride)를 7:1.5: 1.5의중량비로흔합하고， N-메틸피롤리돈 (NMP)용액을이용하여 슬러리를제조한후，제조한슬러리를알루미늄포일위에도포하고, 120°C 진공오본에서 10시간동안건조하여양극을제조하였다.글로브박스안에서 제조된양극과함께나트륨메탈을반대전극으로, 0.8M NaClO4을함유하는 에틸렌카보네이트 /디에틸렌카보네이트 (ethylenecarbonate/diethylenecarbonate)(l/ 1부피비)을전해질로사용하여전지를제조하였다.
[96] 제조된나트륨이차전지에대해， 1.7(방전) -4.0(층전) V vs. Na/Na+전압범위에서 0.05및 0.2C로층방전을실시하였다.층방전싸이클은충전 -방전순으로 수행되었다.
[97]
[98] 도 1은제조예 1에서제조된나트륨철피로인산염을관찰한주사전자현미경 사진으로도 1(a)는고배율주사전자현미경사진이며，도 1(b)는저배율
주사전자현미경사진이다.도 1에서알수있듯이，수 μιη의크기를갖는일차 입자들이뭉쳐형성된 2차입자상으로나트륨철피로인산염이제조됨을 확인하였다.
[99] 도 2는제조예 1내지제조예 3에서제조된나트륨전이금속피로인산염의
X-선회절분석결과를도시한도면으로,도 2에서알수있듯이,삼사정계의 제조예 1에서 Na3.12Fe2.44(P207)2,제조예 2에서 Na ^Fe^Mn^X^O^및제조예 ' 3에서 Ν .12Μη2.44(Ρ207)2가제조됨을확인하였다.도 3은 X선회결결과에의한 구조및측정조성에기반한구조시뮬레이션 (GSAS rietveld refinement)결과로, 제조된나트륨전이금속피로인산염이 P-1공간군을가짐을알수있었으며，도 4과같이 , [100]및 [이이방향으로거대한채널이형성되어이온반경이큰 나트륨이온의탈삽입통로를제공함을알수있다.
[100] 도 5는제조예 1에서제조된나트륨철피로인산염을양극활물질로함유하는 제조예 4의나트륨이차전지의층방전특성을평가한결과로,
1.7(방전) -4.0(층전) V vs. Na/Na+전압범위에서 0.05C로층방전을수행한 결과이다.도 5의결과에서알수있듯이，첫번째층방전시，제조직후나트륨철 피로인산염에함유된나트륨이온의탈착이이루어진후,방전시나트륨이온이 삽입이되는가역적인나트륨이온의탈 /삽입반웅이이루어지며,약 85 mAh/g 이상의가역용량을가짐을알수있다.
[101] 도 6는제조예 1에서제조된나트륨철피로인산염을양극활물질로함유하는 제조예 4의나트륨이차전지의충방전싸이클횟수에따른가역용량을정리 도시한도면으로, 1.7(방전) -4.0(층전) V vs. Na/Na+전압범위에서 0.05C (도 6의 C/20)및 0.2C (도 6의 C/5)로층방전을수행한결과이다.도 6에서알수있듯이, 나트륨이은의가역적인삽입및탈착이원활히수행됨을알수있으며, 60회 싸이클까지도안정적인층방전특성을가짐을알수있으며，충방전
싸이클에서는나트륨철피로인산염구조에 2개의 Na+가가역적으로
삽입 /탈리됨을알수있다.
[102] 도 7은제조예 1에서제조된나트륨철피로인산염을양극활물질로함유하는 제조예 4의나트륨이차전지의 1C (도 7의 1C)내지 0.05C (도 7의 C/20)의전류 ' 밀도에따른가역용량의변화를도시한도면이다.도 7에서알수있듯이
0.1C (도 6의 C/10)의전류밀도에서도 SOmAhg-1이상의가역용량을가짐을알수 있으며， 1C (도 6의 1C)의전류밀도에서도 65πιΑ1ι^이상의가역용량이 유지됨을알수있다.
[103] 도 8은구조적변화여부를확인하기위해，층전상태의나트륨철피로인산염을 GSAS프로그램을사용하여 Rietveld refinement통해결정구조를분석한 도면으로，도 9의충전상태에서의양극활물질에대한 Rietveld refinement 결정구조분석결과에서알수있듯이，나트륨이온의삽입또는탈리시에도 삼사정계구조가유지됨을확인하였다.
[104] 이상과같이본발명에서는특정된사항들과한정된실시예및도면에의해 설명되었으나이는본발명의보다전반적인이해를돕기위해서제공된것일 뿐，본발명은상기의실시예에한정되는것은아니며，본발명이속하는 분야에서통상의지식을가진자라면이러한기재로부터다양한수정및변형이 가능하다.
[105] 따라서，본발명의사상은설명된실시예에국한되어정해져서는아니되며, 후술하는특허청구범위뿐아니라이특허청구범위와균등하거나등가적변형이 있는모든것들은본발명사상의범주에속한다고할것이다.

Claims

청구범위 하기화학식 1을만족하는나트륨전이금속피로인산염을 함유하는이차전지용양극활물질ᅳ
(화학식 1)
Na3.12-x2 ,M1 a ylM2 b y2(P207)2
(화학식 1에서 Ac는 1또는 2인 c의원자가를갖는알칼리금속및 알칼리토금속에서하나또는둘이상선택된원소 (A)를의미하며， xl는 0≤xl≤0.5인실수이고， x2는 c와 xl의곱 (x2 = xl * c)이며， M! a 는 a의원자가를갖는전이금속및 12내지 14족에서하나또는둘 이상선택된원소 (Μ,)를의미하고, 는 b의원자가를갖는 전이금속및 12내지 14족에서하나또는둘이상선택된원소 (M2 )를의미하며， a와 b는서로같거나상이하며 , a와 b는서로 독립적으로 2내지 4의정수이며, yl은 0<yl≤2.44인실수이고, y2는 0≤y2≤2.44인실수이다.)
제 1항에있어서，
상기나트륨전이금속피로인산염은삼사정계 (Triclinic phase)인 이차전지용양극활물질.
제 1항에있어서，
상기나트륨전이금속피로인산염은 P-1공간군 (space group)인 이차전지용양극활물질.
제 1항에있어서，
상기나트륨전이금속피로인산염은화학식 1에서, (yl * a) + (y2 * b) = 4.88을만족하는이차전지용양극활물질.
제 1항에있어서，
상기 Ml및 M2는서로독립적으로， Co, Ni, Fe, Mn, V, Cu, Ti, Al, Cr, Mo및 Nb에서하나또는둘이상선택된원소인이차전지용 양극활물질. ' 제 5항에있어서，
상기 A는 Li, Na, Mg및 Ca에서하나또는둘이상선택된원소인 이차전지용양극활물질.
제 1항에있어서，
상기나트륨전이금속피로인산염은적어도철 (Fe),망간 (Mn)또는 철과망간을함유하는이차전지용양극활물질.
제 1항에있어서,
상기양극활물질은 1.7V/4.0V및 0.05C의층방전조건에서
80mAh/g이상의용량을갖는이차전지용양극활물질.
제 1항내지제 8항에서선택된어느한항에있어서， 상기양극활물질은나트륨이차전지용인이차전지용양극활물질. [청구항 10] 제 1항내지제 8항에서선택된어느한항에있어서，
상기양극활물질은탄소를더함유하는이차전지용양극활물질. [청구항 11] 제 1항내지제 8항에서선택된어느한항에따른양극활물질을 포함하는나트륨이차전지 .
PCT/KR2013/007398 2013-08-16 2013-08-16 이차전지용 양극 활물질 WO2015023017A1 (ko)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US14/904,237 US10026520B2 (en) 2013-08-16 2013-08-16 Positive electrode active material for secondary battery
PCT/KR2013/007398 WO2015023017A1 (ko) 2013-08-16 2013-08-16 이차전지용 양극 활물질
JP2016534518A JP2016534509A (ja) 2013-08-16 2013-08-16 二次電池用正極活物質

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/KR2013/007398 WO2015023017A1 (ko) 2013-08-16 2013-08-16 이차전지용 양극 활물질

Publications (1)

Publication Number Publication Date
WO2015023017A1 true WO2015023017A1 (ko) 2015-02-19

Family

ID=52468397

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2013/007398 WO2015023017A1 (ko) 2013-08-16 2013-08-16 이차전지용 양극 활물질

Country Status (3)

Country Link
US (1) US10026520B2 (ko)
JP (1) JP2016534509A (ko)
WO (1) WO2015023017A1 (ko)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018069957A1 (ja) * 2016-10-11 2018-04-19 富士通株式会社 二次電池用正極材料、及びその製造方法、並びにリチウムイオン二次電池
RU2718878C1 (ru) * 2019-03-28 2020-04-15 Федеральное государственное бюджетное образовательное учреждение высшего образования "Московский государственный университет имени М.В. Ломоносова" (МГУ) Соединение для электродного материала металл-ионных аккумуляторов, электродный материал на его основе, электрод и аккумулятор на основе электродного материала
CN111446429A (zh) * 2020-03-27 2020-07-24 珠海冠宇电池股份有限公司 一种聚多阴离子正极材料及其制备方法和用途
WO2022102961A1 (ko) * 2020-11-11 2022-05-19 삼성전자주식회사 양극활물질, 이를 포함하는 양극 및 리튬전지, 및 그 제조방법

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116364914A (zh) * 2017-04-27 2023-06-30 日本电气硝子株式会社 钠离子二次电池用正极活性物质
JP7101005B2 (ja) * 2018-03-22 2022-07-14 Fdk株式会社 正極活物質の製造方法
JP7131258B2 (ja) * 2018-09-27 2022-09-06 株式会社豊田自動織機 複合粒子の製造方法
US20240145679A1 (en) * 2019-10-04 2024-05-02 The Research Foundation For The State University Of New York Composition and method for rechargeable battery
CN113921779B (zh) * 2021-09-08 2022-12-13 西北大学 一种nasicon型钠快离子导体材料、制备方法及应用
CN116053470B (zh) * 2023-04-03 2023-06-20 中南大学 一种铁基复合正极活性材料及其制备方法和应用

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013031331A1 (ja) * 2011-08-29 2013-03-07 トヨタ自動車株式会社 ナトリウム電池用正極活物質及びその製造方法

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7008566B2 (en) * 2003-04-08 2006-03-07 Valence Technology, Inc. Oligo phosphate-based electrode active materials and methods of making same
US20110008233A1 (en) 2009-07-10 2011-01-13 Semiconductor Energy Laboratory Co., Ltd. Positive electrode active material
GB2495279A (en) * 2011-09-30 2013-04-10 Faradion Ltd A condensed polyanion electrode material
JP6066349B2 (ja) * 2012-03-09 2017-01-25 日本電気硝子株式会社 ナトリウムイオン二次電池用正極活物質およびナトリウムイオン二次電池用正極活物質の製造方法
US20130244100A1 (en) * 2012-03-15 2013-09-19 Imra America, Inc. Iron phosphates: negative electrode materials for aqueous rechargeable sodium ion energy storage devices
GB201223473D0 (en) * 2012-12-28 2013-02-13 Faradion Ltd Metal-containing compounds

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013031331A1 (ja) * 2011-08-29 2013-03-07 トヨタ自動車株式会社 ナトリウム電池用正極活物質及びその製造方法

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
ANGENAULT, J. ET AL.: "STRUCTURE OF NA3.12FE2.44(P207)2", EUROPEAN JOURNAL OF SOLID STATE AND INORGANIC CHEMISTRY, vol. 32, no. 1, 1995, pages 335 - 343, Retrieved from the Internet <URL:http://serials.unibo.it/cgi-ser/start/it/spogli/df-s.tcl?prog_art=2889153&language=ITALIANO&view=articoli> *
ERRAGH, FATIMA ET AL.: "Study of the Crystal Structures of Sodium Magnesium and Sodium Nickel Diphosphates", JOURNAL OF SOLID STATE CHEMISTRY, vol. 152, no. 2, 2000, pages 323 - 331 *
HONG, SUNG YOU ET AL.: "Charge carriers in rechargeable batteries: Na ions vs. Li ions", ENERGY & ENVIRONMENTAL SCIENCE, vol. 6, no. 7, 1 July 2013 (2013-07-01), pages 2067 - 2081 *
MARZOUKI, RIADH ET AL.: "Synthesis, Crystal Structure and Electrical Properties of a New Mixed Compound (Na0.71Ag0.29)2CoP2O7", CRYSTAL STRUCTURE THEORY AND APPLICATIONS, vol. 1, no. 3, 2012, pages 68 - 73 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018069957A1 (ja) * 2016-10-11 2018-04-19 富士通株式会社 二次電池用正極材料、及びその製造方法、並びにリチウムイオン二次電池
JPWO2018069957A1 (ja) * 2016-10-11 2019-06-27 富士通株式会社 二次電池用正極材料、及びその製造方法、並びにリチウムイオン二次電池
RU2718878C1 (ru) * 2019-03-28 2020-04-15 Федеральное государственное бюджетное образовательное учреждение высшего образования "Московский государственный университет имени М.В. Ломоносова" (МГУ) Соединение для электродного материала металл-ионных аккумуляторов, электродный материал на его основе, электрод и аккумулятор на основе электродного материала
CN111446429A (zh) * 2020-03-27 2020-07-24 珠海冠宇电池股份有限公司 一种聚多阴离子正极材料及其制备方法和用途
WO2022102961A1 (ko) * 2020-11-11 2022-05-19 삼성전자주식회사 양극활물질, 이를 포함하는 양극 및 리튬전지, 및 그 제조방법

Also Published As

Publication number Publication date
JP2016534509A (ja) 2016-11-04
US20160164095A1 (en) 2016-06-09
US10026520B2 (en) 2018-07-17

Similar Documents

Publication Publication Date Title
Mohamed et al. Recent advances in the design of cathode materials for Li-ion batteries
Aravindan et al. LiMnPO 4–A next generation cathode material for lithium-ion batteries
WO2015023017A1 (ko) 이차전지용 양극 활물질
Ahsan et al. Recent progress in capacity enhancement of LiFePO4 cathode for Li-ion batteries
Behm et al. Influence of structure and composition upon performance of tin phosphate based negative electrodes for lithium batteries
JP5830540B2 (ja) 非水電解質二次電池用正極材料およびそれを用いた非水電解質二次電池
Kou et al. High rate capability and cycle performance of Ce-doped LiMnPO4/C via an efficient solvothermal synthesis in water/diethylene glycol system
Liang et al. Practical Cathodes for Sodium‐Ion Batteries: Who Will Take The Crown?
Zhang et al. Selecting substituent elements for LiMnPO4 cathode materials combined with density functional theory (DFT) calculations and experiments
Zhu et al. Recent advances on Fe-and Mn-based cathode materials for lithium and sodium ion batteries
Selinis et al. A review on the anode and cathode materials for lithium-ion batteries with improved subzero temperature performance
JP5681796B2 (ja) 二次電池用正極材料およびそれを用いた二次電池
JP2011523171A (ja) 電気化学的エネルギー貯蔵用の鉄オキシフルオライド電極
EP2546194A1 (en) Phosphate compound, positive electrode for secondary battery and method for producing secondary battery
JP4773964B2 (ja) ホウ素置換されたリチウム挿入化合物、電極の活物質、電池およびエレクトロクロミックデバイス
Arinicheva et al. Ceramics for electrochemical storage
Aravindan et al. Superior lithium storage properties of carbon coated Li2MnSiO4 cathodes
Yi et al. Electrochemical performance of LiMnPO 4 by Fe and Zn co-doping for lithium-ion batteries
Yamashita et al. Demonstration of Co3+/Co2+ electrochemical activity in LiCoBO3 cathode at 4.0 V
KR101352793B1 (ko) 이차전지용 양극재료 및 이의 제조방법
Zhao et al. Phase transitions and related electrochemical performances of Li-Rich layered cathode materials for high-energy lithium ion batteries
Doeff Batteries: overview of battery cathodes
WO2012133730A1 (ja) 活物質、活物質の製造方法、電極、リチウムイオン二次電池
JP4823540B2 (ja) 電極材料の製造方法と電極材料及び電極並びにリチウム電池
KR101345625B1 (ko) 이산화규소 및 이산화규소를 함유한 광물을 이용한 리튬 이차전지용 음극활물질 및 그 제조방법

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13891508

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2016534518

Country of ref document: JP

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 14904237

Country of ref document: US

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 13891508

Country of ref document: EP

Kind code of ref document: A1