CN101694876A - Lithium-rich manganese-based anode material and preparation method thereof - Google Patents

Abstract

The invention relates to the positive electrode material technology for lithium-ion secondary batteries, in particular to the lithium-rich manganese-based positive electrode material Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M =Co, Al, Ti, Mg, Cu) and their preparation methods. The lithium-rich manganese-based cathode material of the present invention has a general formula: Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu), where 0<x≤0.5, when M=Co, Al, 0<y<2x, a=b=y/2; when M=Ti, 0<y<(2-x)/ 3. a=0, b=y; when M=Mg, Cu, 0<y<x, a=y, b=0. The invention has high discharge specific capacity, excellent cycle performance at normal temperature and high temperature, good safety, low raw material cost and production cost, and high cost performance.

Description

Lithium-rich manganese-based cathode material and preparation method thereof

technical field

The invention relates to the positive electrode material technology for lithium-ion secondary batteries, in particular to the lithium-rich manganese-based positive electrode material Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M =Co, Al, Ti, Mg, Cu) and their preparation methods.

Background technique

Lithium-ion battery cathode material is the key raw material of lithium-ion batteries. Its performance determines the performance of lithium-ion batteries, and its price determines the cost of lithium-ion batteries. At present, the cathode materials on the market are mainly lithium cobalt oxide. , materials such as spinel lithium manganate, nickel cobalt lithium manganese oxide, nickel cobalt lithium oxide, and lithium iron phosphate also occupy a certain market share. Lithium cobaltate is the first positive electrode material to be commercialized. It has stable performance, simple preparation, and mature technology. However, the global cobalt resources are in short supply, and my country is a cobalt-poor country. Therefore, the production cost of lithium cobaltate is very high, and the product price remains high. , and cobalt has certain toxicity, the development of lithium cobaltate has been hindered, and other materials are needed as its substitutes. Spinel lithium manganese oxide is currently the cheapest cathode material on the market, and has good safety, but its specific capacity is low and its high-temperature cycle performance is poor. Compared with lithium cobalt oxide, lithium nickel cobalt manganese oxide has lower price, higher specific capacity, better safety, and is more environmentally friendly, but its platform voltage is lower and its compaction density is lower. Lithium nickel cobalt oxide has good electrochemical properties, but its price is higher than that of lithium nickel cobalt manganese oxide, and its safety is poor.

Compared with the cathode materials currently on the market, the lithium-rich manganese-based cathode material Li[Li _(1-2x)/3 Ni _x Mn _(2-x)/3 ]O ₂ is dominated by manganese as a transition metal element, and manganese resources Rich, cheap, and environmentally friendly, it is a new type of material with good development prospects. Li[Li _(1-2x)/3 Ni _x Mn _(2-x)/3 ]O ₂ material is a solid solution of Li ₂ MnO ₃ and LiMn _0.5 Ni _0.5 O ₂ , which is a composite structure. Under the charging voltage, it has a very high specific capacity. It is reported that the initial discharge specific capacity of Li _1.2 Ni _0.2 Mn _0.6 O ₂ material at 2-4.8V with a current of 20mA/g is 288mAh/g, but its cycle is stable The performance is very poor, and the discharge specific capacity drops to 213mAh/g after 30 cycles. Judging from the Li[Li _(1-2x)/3 Ni _x Mn _(2-x)/3 ]O ₂ materials reported in the current literature, there are obvious defects. First, the Li[ The high specific capacity of Li _(1-2x)/3 Ni _x Mn _(2-x)/3 ]O ₂ material is obtained by charging and discharging at a very low rate. When the rate increases, the specific capacity drops rapidly , the rate performance of the material is poor; second, the Li[Li _(1-2x)/3 Ni _x Mn _(2-x)/3 ]O ₂ material can only get a higher rate when it is charged above 4.5V If the specific capacity is charged at a lower voltage, the specific capacity obtained is much lower than that of lithium cobalt oxide and other materials. In summary, the performance of the current Li[Li _(1-2x)/3 Ni _x Mn _(2-x)/3 ]O ₂ material does not meet the requirements of practical applications, so it is urgent to improve its performance in order to Make it have better performance, realize industrialized production as soon as possible.

Contents of the invention

The purpose of the present invention is to provide a lithium-rich manganese-based positive electrode material Li[Li _(1-2x)/3 Ni _xa M with high specific capacity, high rate, low price, excellent electrochemical performance, good structural stability and high safety. _y Mn _(2-x)/3-b ]O ₂ (M = Co, Al, Ti, Mg, Cu).

Another object of the present invention is to provide the lithium-rich manganese-based cathode material Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al , Ti, Mg, Cu) preparation method.

The technical solution of the present invention: a lithium-rich manganese-based positive electrode material, the general formula of which is:

Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu),

where 0<x≤0.5,

When M=Co, Al, 0<y<2x, a=b=y/2;

When M=Ti, 0<y<(2-x)/3, a=0, b=y;

When M=Mg, Cu, 0<y<x, a=y, b=0.

The microstructure of the lithium-rich manganese-based cathode material is a layered composite structure of Li ₂ MnO ₃ and LiMO ₂ .

The preparation method of the lithium-rich manganese-based positive electrode material comprises the following steps:

a) dissolving soluble nickel, manganese, and M salt in deionized water at a molar ratio of (x-a):[(2-x)/3-b]:y, and preparing a solution with a total concentration of 0.5～4mol/L, Wherein, 0<x≤0.5, when M=Co, Al, 0<y<2x, a=b=y/2;; when M=Ti, 0<y<(2-x)/3, a =0, b=y; when M=Mg, Cu, 0<y<x, a=y, b=0;

b) preparing an alkali solution or a mixed solution of alkali and ammonia water, the alkali concentration is 1-8 mol/L, and the ammonia water molar concentration is 0.1-4 mol/L;

c) Add deionized water accounting for 10%-30% of the total volume of the reactor in the reactor, pump the nickel, manganese, and M salt solutions into the reactor, and simultaneously mix the alkali solution or the alkali with the The mixed solution of ammonia water is pumped into the reactor, the materials in the reactor are stirred, the temperature and pH value in the reactor are controlled, and the precursor [Ni _{(xa)/(x+(2-x) /3)} M _{y/(x+(2-x)/3) Mn ((2-x)/3-b)/(x+(2-x)/3)} ](OH) Precipitation;

d) After the precursor is filtered, washed, and dried, the ratio of the moles of lithium to the total moles of nickel, manganese, and M with the lithium compound is {[1+(1-2x)/3]/[x-a +y+(2-x)/3-b]+z}:1 ratio for uniform mixing, wherein, 0<x≤0.5, 0≤z≤0.1, when M=Co, Al, 0<y<2x , a=b=y/2; when M=Ti, 0<y<(2-x)/3, a=0, b=y; when M=Mg, Cu, 0<y<x, a =y,b=0;

e) firing the homogeneous mixture of the precursor and the lithium compound at high temperature to obtain

Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu) material.

The soluble nickel salt described in step (a) can be one or its mixed salt in nickel sulfate, nickel nitrate, nickel chloride, nickel acetate; Soluble manganese salt can be manganese sulfate, manganese nitrate, manganese chloride, manganese acetate One or its mixed salt; soluble cobalt salt can be one of cobalt sulfate, cobalt nitrate, cobalt chloride, cobalt acetate or their mixed salt; soluble aluminum salt can be one of aluminum sulfate, aluminum nitrate, aluminum chloride or its mixed salt; soluble titanium salt can be titanium tetrachloride; soluble magnesium salt can be one of magnesium sulfate, magnesium chloride, magnesium nitrate, magnesium acetate or its mixed salt; soluble copper salt can be copper sulfate, copper chloride, One of copper nitrate and copper acetate or their mixed salts.

The alkali described in step (b) can be a kind of in sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, or the mixture of sodium hydroxide, potassium hydroxide, lithium hydroxide, and its concentration is 1- 8mol/L.

The nickel, manganese, and M solutions described in step (c) are added to the reactor in the form of spraying on the upper part of the reactor, and the alkali solution is introduced from the lower part of the reactor.

The temperature in the reaction kettle described in the step (c) is 40-60° C., and the pH value is between 8-12.

The lithium compound described in step (d) can be one or its mixture in lithium hydroxide, lithium carbonate, lithium nitrate, the total lithium molar number and nickel, manganese, M in a single lithium salt or mixed lithium salt The molar ratio is {[1+(1-2x)/3]/[x-a+y+(2-x)/3-b]+z}: 1, where 0<x≤0.5, 0≤ z≤0.1, when M=Co, Al, 0<y<2x, a=b=y/2;; when M=Ti, 0<y<(2-x)/3, a=0, b =y; when M=Mg, Cu, 0<y<x, a=y, b=0.

The filtration and washing described in step (d) are to make the total content of Na ⁺ and K ⁺ in the precursor less than 300ppm, the total content of sulfate ion and chloride ion is less than 0.5%, and the drying is carried out between 80-150°C .

The high-temperature firing described in step (e) is to heat up to 400-800°C at a heating rate of 1-20°C/min, keep the temperature for 2-20h, and then heat up to 800°C at a heating rate of 1-20°C/min. ～1100℃, keep warm for 4～40h.

Specifically, soluble nickel, manganese, and M salts (such as sulfate, chloride, nitrate, and acetate) are used in a molar ratio of (xa):[(2-x)/3-b]:y Dissolved in deionized water to form a uniform transparent solution with a total molar concentration of transition metal ions of 0.5-4mol/L, where 0<x≤0.5, when M=Co, Al, 0<y<2x, a=b= y/2; when M=Ti, 0<y<(2-x)/3, a=0, b=y; when M=Mg, Cu, 0<y<x, a=y, b= 0. Prepare an alkali solution with a molar concentration of 1-8mol/L, or prepare a mixed solution of alkali and ammonia water, the molar concentration of ammonia water is 0.1-4mol/L, and the alkali can be sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate wait. Add a certain amount of deionized water into the reactor, pump the nickel, manganese, M salt solution and alkali solution (or the mixed solution of alkali and ammonia) into the reactor at the same time, and completely react to form mixed metal hydroxide During the reaction process, the materials in the reactor are stirred, and the temperature in the reactor is controlled at 40-60 ° C and the pH value is between 8 and 12. Adjust the lye flow rate to control the pH. The precipitate was filtered, washed, dried, and ground into powder to obtain the precursor [Ni _{(xa)/(x+(2-x)/3)} M _{y/(x+(2-x)/3)} Mn _{(( 2-x)/3-b)/(x+(2-x)/3)} ](OH) ₂ , the prepared precursor and lithium compound are calculated according to the moles of lithium and the total moles of nickel, manganese and M The ratio is {[1+(1-2x)/3]/[x-a+y+(2-x)/3-b]+z}: 1 for uniform mixing, where 0<x≤0.5 , 0≤z≤0.1, when M=Co, Al, 0<y<2x, a=b=y/2; when M=Ti, 0<y<(2-x)/3, a=0 , b=y; when M=Mg, Cu, 0<y<x, a=y, b=0, the lithium compound can be lithium carbonate, lithium hydroxide, lithium nitrate or a mixture thereof. The homogeneous mixture of precursor and lithium compound is heated to 400-800°C at a heating rate of 1-20°C/min, kept for 2-20h, and then heated to 800-1100°C at a heating rate of 1-20°C/min. Insulated for 4 to 40 hours to obtain the lithium-rich manganese-based positive electrode material Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu).

Advantages of the present invention:

High specific capacity. Use the Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu) material described in the present invention as the positive electrode material The lithium-ion battery produced has a high charging cut-off voltage, which can reach 4.6V, and when charging and discharging between 2.5 and 4.6V, the discharge specific capacity can reach 250mAh/g. Moreover, a high discharge specific capacity can also be obtained at a lower charging voltage, and the discharge specific capacity can reach 166mAh/g under the charging and discharging conditions of 2.75-4.2V and 0.1C.

The cycle performance is stable. Use the Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu) material described in the present invention as the positive electrode material When the manufactured lithium-ion battery is charged and discharged at 1C between 2.75-4.2V, the initial discharge specific capacity is 141mAh/g, the capacity retention rate is 97% after 300 cycles, and the capacity retention rate is 74% after 1600 cycles; Excellent cycle performance, 6C discharge specific capacity is 94% of 0.5C;

High temperature cycle stability and high specific capacity. When charging and discharging under the conditions of 2.75-4.2V, 1C, 55°C, the initial discharge specific capacity is 157mAh/g, and the capacity retention rate after 180 cycles is 92.2%.

Good security. Use the Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu) material described in the present invention as the positive electrode material The manufactured lithium-ion battery can pass the external short circuit and nail penetration test, can withstand 5C10V overcharge, has good thermal stability, and the maximum safe temperature of the environment is 170°C.

Environmentally friendly material. The Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu) material of the present invention has less cobalt content or It does not contain cobalt and is an environmentally friendly material.

low cost. The Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu) material described in the present invention is mainly manganese , so the cost is very low, and the cost performance advantage is obvious.

The preparation method of the Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu) material provided by the present invention is simple and convenient, Conducive to large-scale industrial production.

Description of drawings

Fig. 1 XRD pattern of Li[Li _0.067 Ni _0.3 Cu _0.1 Mn _0.533 ]O ₂ material.

Fig. 2 SEM image of Li[Li _0.067 Ni _0.3 Co _0.2 Mn _0.433 ]O ₂ material.

Fig. 3 The initial charge-discharge curve of Li[Li _0.2 Ni _0.19 Al _0.02 Mn _0.59 ]O ₂ material (2.5-4.6V, 0.1C, room temperature).

Fig. 4 Discharge specific capacity of Li[Li _0.2 Ni _0.19 Al _0.02 Mn _0.59 ]O ₂ material at different rates (2.75-4.2V, room temperature).

Detailed ways

The content of the present invention is described in detail below through the examples, and the examples are provided to facilitate understanding of the present invention, and are by no means limiting the invention of the patent.

The molecular formula of the lithium-rich manganese-based cathode material provided by the present invention is Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu), wherein 0<x≤0.5, when M=Co, Al, 0<y<2x, a=b=y/2; when M=Ti, 0<y<(2-x)/3 , a=0, b=y; when M=Mg, Cu, 0<y<x, a=y, b=0.

Lithium-rich manganese-based material Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu) provided by the present invention It is used as a positive electrode material in the preparation of lithium-ion batteries.

The lithium-rich manganese-based cathode material Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al, Ti, Mg, Cu ) preparation method comprises the following steps:

a. soluble nickel, manganese, M salt are dissolved in deionized water in a molar ratio of (x-a): [(2-x)/3-b]: y, and the total concentration is prepared into a solution of 0.5～4mol/L, Wherein, 0<x≤0.5, when M=Co, Al, 0<y<2x, a=b=y/2; when M=Ti, 0<y<(2-x)/3, a= 0, b=y; when M=Mg, Cu, 0<y<x, a=y, b=0;

b. Prepare an alkali solution or a mixed solution of alkali and ammonia water, the alkali concentration is 1-8mol/L, and the molar concentration of ammonia water is 0.1-4mol/L;

c. add a certain amount of deionized water in the reactor, pump the nickel, manganese, M salt solution into the reactor, and pump the alkali solution into the reactor simultaneously, Stir the materials, control the temperature and pH value in the reactor, and form precursor precipitation through co-precipitation reaction;

d. After the precursor is filtered, washed, and dried, the ratio of the moles of lithium to the total moles of nickel, manganese, and M with the lithium compound is {[1+(1-2x)/3]/[x-a +y+(2-x)/3-b]+z}:1 ratio for uniform mixing, wherein, 0<x≤0.5, 0≤z≤0.1, when M=Co, Al, 0<y<2x , a=b=y/2; when M=Ti, 0<y<(2-x)/3, a=0, b=y; when M=Mg, Cu, 0<y<x, a =y,b=0;

e. Sinter the homogeneous mixture of precursor and lithium compound at high temperature to obtain Li[Li _(1-2x)/3 Ni _xa M _y Mn _(2-x)/3-b ]O ₂ (M=Co, Al , Ti, Mg, Cu) materials.

The soluble nickel described in step a, manganese, M salt can be sulfate, chloride salt, nitrate, acetate or mixed salt, and the alkali described in step b can be sodium hydroxide, potassium hydroxide, lithium hydroxide, Sodium carbonate, etc., or a mixture of two or three of sodium hydroxide, potassium hydroxide, and lithium hydroxide. The lithium compound described in step c can be lithium hydroxide, lithium carbonate, lithium nitrate or a mixture thereof, the temperature described in step c is between 40～60° C., the pH value is between 8～12, by adjusting the lye (or The mixed solution of alkali and ammonia water) flow rate to control the pH value. The high-temperature sintering described in step e is to raise the temperature of the homogeneous mixture of the precursor and the lithium compound to 400-800°C at a heating rate of 1-20°C/min, keep it warm for 2-20h, and then raise the temperature at a rate of 1-20°C/min Raise the temperature at a rate of 800-1100°C and keep it warm for 4-40h.

Example 1

The molar percentage of nickel, manganese and aluminum metal ions is 0.123:0.850:0.027. Dissolve nickel sulfate, manganese sulfate and aluminum sulfate in deionized water to prepare a uniform and transparent solution with a total concentration of manganese, nickel and aluminum ions of 2mol/L , prepare a 4mol/L sodium hydroxide solution, pump the mixed metal salt solution and the sodium hydroxide solution into the reactor at the same time for co-precipitation reaction. The precipitated product was filtered, washed and dried to obtain the metal hydroxide precursor Mn _0.85 Ni _0.123 Al _0.027 (OH) ₂ .

The precursor and lithium carbonate are uniformly mixed according to the ratio of the molar number of lithium to the total molar number of nickel, manganese, and aluminum of 1.77:1, and the uniformly mixed powder is compacted and kept at 450°C for 2 hours. Then the temperature was raised to 800° C. and kept for 40 hours to obtain Li[Li _0.267 Ni _0.09 Al _0.02 Mn _0.623 ]O ₂ , a lithium-rich manganese-based material.

AA batteries were assembled using the prepared Li[Li _0.267 Ni _0.09 Al _0.02 Mn _0.623 ]O ₂ as the cathode material. Under the charging and discharging conditions of 2.5-4.6V and 0.1C, the discharge specific capacity is 250mAh/g.

Example 2

With the molar percentage of nickel, manganese, and aluminum metal ions as 0.238:0738:0.025, nickel chloride, manganese sulfate, and aluminum chloride are dissolved in deionized water, and the total concentration of manganese, nickel, and aluminum ions is 2mol/L. Uniform and transparent solution, prepare 4mol/L sodium hydroxide solution, pump the mixed metal salt solution and sodium hydroxide solution into the reactor at the same time for co-precipitation reaction. The precipitated product was filtered, washed and dried to obtain the metal hydroxide precursor Mn _0.738 Ni _0.238 Al _0.025 (OH) ₂ .

The precursor and lithium carbonate are uniformly mixed according to the ratio of the molar number of lithium to the total molar number of nickel, manganese, and aluminum of 1.54:1, and the uniformly mixed powder is compacted and kept at 550°C for 4 hours. Then the temperature was raised to 900° C. and kept for 20 hours to obtain Li[Li _0.2 Ni _0.19 Al _0.02 Mn _0.59 ]O ₂ , a lithium-rich manganese-based material.

AA batteries were assembled with Li[Li _0.2 Ni _0.19 Al _0.02 Mn _0.59 ]O ₂ as the cathode material. Under the charging and discharging conditions of 2.5-4.6V and 0.1C, the discharge specific capacity is the same as that of the material in Example 1, which is also 250mAh/g. Charging and discharging in other voltage ranges also shows a higher capacity. When charging and discharging at 2.5-4.2V and 0.3C, the discharge specific capacity is between 150-160mAh/g. When charging and discharging at 2.5-4.3V and 0.3C, The discharge specific capacity is between 160-170mAh/g, 2.5-4.4V, 0.3C charge and discharge, the discharge specific capacity is between 170-180mAh/g, 2.5-4.5V, 0.3C charge and discharge, the discharge specific capacity is Between 180-190mAh/g. Under the conditions of 2.75-4.2V, 1C, the charge-discharge cycle is carried out, the initial discharge specific capacity is 141mAh/g, the capacity retention rate after 300 cycles is 97%, and the capacity retention rate after 1600 cycles is 74%; the rate cycle performance is excellent , 6C discharge specific capacity is 94% of 0.5C; high temperature cycle stability and high specific capacity, when charging and discharging under the conditions of 2.75-4.2V, 1C, 55 ℃, the initial discharge specific capacity is 157mAh/g, after 180 cycles The capacity retention rate was 92.2%.

Example 3

Dissolve nickel sulfate, manganese sulfate, and copper sulfate in deionized water with a molar percentage of nickel, manganese, and copper metal ions of 0.231:0.654:0.115 to prepare a uniform transparent solution with a total concentration of manganese, nickel, and copper ions of 2 mol/L , prepare a 4mol/L potassium hydroxide solution, pump the mixed metal salt solution and the sodium hydroxide solution into the reactor at the same time for co-precipitation reaction. The precipitated product was filtered, washed and dried to obtain the metal hydroxide precursor Mn _0.654 Ni _0.231 Cu _0.115 (OH) ₂ .

The precursor and lithium carbonate are uniformly mixed according to the ratio of the moles of lithium to the total moles of nickel, manganese, and copper of 1.35:1, and the uniformly mixed powder is compacted and kept at 500°C for 15 hours. Then the temperature was raised to 1000° C. and kept for 8 hours to obtain Li[Li _0.133 Ni _0.2 Cu _0.1 Mn _0.567 ]O ₂ , a lithium-rich manganese-based material.

AA batteries were assembled with Li[Li _0.133 Ni _0.2 Cu _0.1 Mn _0.567 ]O ₂ as the cathode material. Under 2.5-4.6V, 1C charge and discharge conditions, the discharge specific capacity is 225mAh/g.

Example 4

The molar percentage of nickel, manganese and copper metal ions is 0.322:0.571:0.107. Dissolve nickel sulfate, manganese sulfate and copper sulfate in deionized water to prepare a uniform and transparent solution with a total concentration of manganese, nickel and copper ions of 2mol/L , prepare a 2mol/L sodium carbonate solution, and pump the mixed metal salt solution and the sodium carbonate solution into the reactor simultaneously for co-precipitation reaction. The precipitated product was filtered, washed and dried to obtain the carbonate precursor Mn _0.571 Ni _0.322 Cu _0.107 CO ₃ .

The precursor and lithium carbonate are uniformly mixed according to the ratio of the moles of lithium to the total moles of nickel, manganese, and copper of 1.18:1, and the uniformly mixed powder is compacted and kept at 600°C for 20 hours. Then the temperature was raised to 1100° C. and kept for 4 hours to obtain Li[Li _0.067 Ni _0.3 Cu _0.1 Mn _0.533 ]O ₂ , a lithium-rich manganese-based material.

The XRD pattern has a sharp front and high diffraction intensity, and the material has a layered structure and a complete crystal form.

AA batteries were assembled using Li[Li _0.067 Ni _0.3 Cu _0.1 Mn _0.533 ]O ₂ as the cathode material. Under 2.5-4.6V, 1C charge and discharge conditions, the discharge specific capacity is 220mAh/g.

Example 5

Dissolve nickel sulfate, manganese sulfate, and manganese sulfate in deionized water with a molar percentage of nickel, cobalt, and manganese metal ions of 0.322:0.214:0.464 to form a uniform transparent solution with a total concentration of nickel, cobalt, and manganese ions of 1mol/L , Prepare a mixed solution of 2mol/L sodium hydroxide and 3mol/L ammonia water, and pump the mixed metal salt solution and sodium hydroxide solution into the reactor at the same time for coprecipitation reaction. The precipitated product was filtered, washed and dried to obtain a metal hydroxide precursor Ni _0.322 Co _0.214 Mn _0.464 (OH) ₂ .

Mix the precursor and lithium carbonate uniformly according to the ratio of the moles of lithium to the total moles of nickel and manganese as 1.18:1, compact the uniformly mixed powder, keep it at 750°C for 10 hours, and then heat up The temperature was kept at 900° C. for 30 hours to obtain the lithium-rich manganese-based material Li[Li _0.067 Ni _0.3 Co _0.2 Mn _0.433 ]O ₂ .

AA batteries were assembled with Li[Li _0.067 Ni _0.3 Co _0.2 Mn _0.433 ]O ₂ as the cathode material. The discharge specific capacity is 160mAh/g when charging and discharging under the condition of 2.75-4.2V and 1C.

Claims (10)

1. lithium-rich manganese-based anode material, its general formula is:

Li[Li _(1-2x)/3Ni _x-aM _yMn _(2-x)/3-b]O ₂

Wherein M=Co, Al, Ti, Mg, Cu, 0＜x≤0.5,

When M=Co, Al, 0＜y＜2x, a=b=y/2;

When M=Ti, 0＜y＜(2-x)/3, a=0, b=y;

When M=Mg, Cu, 0＜y＜x, a=y, b=0.

2. lithium-rich manganese-based anode material according to claim 1 is characterized in that: the microstructure of described lithium-rich manganese-based anode material is Li ₂MnO ₃And LiMO ₂Layered composite structure.

3. the preparation method of lithium-rich manganese-based anode material according to claim 1 may further comprise the steps:

A) soluble nickel, manganese, M salt are pressed (x-a): [(2-x)/and 3-b]: the mol ratio of y is dissolved in the deionized water, is mixed with the solution that total concentration is 0.5～4mol/L, wherein, and 0＜x≤0.5, when M=Co, Al, 0＜y＜2x, a=b=y/2; When M=Ti, 0＜y＜(2-x)/3, a=0, b=y; When M=Mg, Cu, 0＜y＜x, a=y, b=0;

B) mixed solution of preparation aqueous slkali or alkali and ammoniacal liquor, alkali concn is 1～8mol/L, the ammoniacal liquor molar concentration is 0.1～4mol/L;

C) in reactor, add the deionized water that accounts for reactor total measurement (volume) 10%-30%, described nickel, manganese, M salting liquid are pumped in the reactor, mixed solution with described aqueous slkali or alkali and ammoniacal liquor is pumped in the reactor simultaneously, material in the reactor is stirred, temperature, pH value in the control reactor generate presoma [Ni by coprecipitation reaction _{(x-a)/(x+ (2-x)/3)}M _{Y/ (x+ (2-x)/3)}Mn _{((2-x)/3-b)/(x+ (2-x)/3)}] (OH) ₂Precipitation;

D) presoma is filtered, washing, oven dry back and lithium compound be that { [1+ (1-2x)/3]/[x-a+y+ (2-x)/3-b]+z}: 1 ratio is evenly mixed by the ratio of the total molal quantity of the molal quantity of lithium and nickel, manganese, M, wherein, 0＜x≤0.5,0≤z≤0.1, when M=Co, Al, 0＜y＜2x, a=b=y/2; When M=Ti, 0＜y＜(2-x)/3, a=0, b=y; When M=Mg, Cu, 0＜y＜x, a=y, b=0;

E) homogeneous mixture of presoma and lithium compound is at high temperature fired, promptly obtained Li[Li _(1-2x)/3Ni _X-aM _yMn _(2-x)/3-b] O ₂Material, wherein M=Co, Al, Ti, Mg, Cu.

4. the preparation method of lithium-rich manganese-based anode material according to claim 3, it is characterized in that: the soluble nickel salt described in the step (a) can be a kind of or its salt-mixture in nickelous sulfate, nickel nitrate, nickel chloride, the nickel acetate; Soluble manganese salt can be a kind of or its salt-mixture in manganese sulfate, manganese nitrate, manganese chloride, the manganese acetate; The solubility cobalt salt can be a kind of or its salt-mixture in cobaltous sulfate, cobalt nitrate, cobalt chloride, the cobalt acetate; Aluminum soluble salt can be a kind of or its salt-mixture in aluminum sulfate, aluminum nitrate, the aluminium chloride; The solubility titanium salt can be a titanium tetrachloride; The solubility magnesium salts can be a kind of or its salt-mixture in magnesium sulfate, magnesium chloride, magnesium nitrate, the magnesium acetate; Soluble copper salt can be a kind of or its salt-mixture in copper sulphate, copper chloride, copper nitrate, the copper acetate.

5. the preparation method of lithium-rich manganese-based anode material according to claim 3, it is characterized in that: the alkali described in the step (b) can be a kind of in NaOH, potassium hydroxide, lithium hydroxide, the sodium carbonate, or the mixture of NaOH, potassium hydroxide, lithium hydroxide, its concentration is 1-8mol/L.

6. the preparation method of lithium-rich manganese-based anode material according to claim 3, it is characterized in that: the nickel described in the step (c), manganese, M solution are to join in the reactor with Sprayable on reactor top, and described aqueous slkali is to feed from the reactor bottom.

7. the preparation method of lithium-rich manganese-based anode material according to claim 3 is characterized in that: the temperature in the reactor described in the step (c) is 40～60 ℃, and the pH value is between 8～12.

8. the preparation method of lithium-rich manganese-based anode material according to claim 3, it is characterized in that: the lithium compound described in the step (d) can be a kind of or its mixture in lithium hydroxide, lithium carbonate, the lithium nitrate, single ratio of planting lithium salts or mixing the total molal quantity of lithium molal quantity total in the lithium salts and nickel, manganese, M is { [1+ (1-2x)/3]/[x-a+y+ (2-x)/3-b]+z}: 1, wherein, 0＜x≤0.5,0≤z≤0.1 is when M=Co, Al, 0＜y＜2x, a=b=y/2; When M=Ti, 0＜y＜(2-x)/3, a=0, b=y; When M=Mg, Cu, 0＜y＜x, a=y, b=0.

9. the preparation method of lithium-rich manganese-based anode material according to claim 3 is characterized in that: the filtration described in the step (d), washing are to make Na in the presoma ⁺, K ⁺Total content is less than 300ppm, and sulfate ion, chloride ion total content are less than 0.5%, and oven dry is to carry out between 80-150 ℃.

10. the preparation method of lithium-rich manganese-based anode material according to claim 3, it is characterized in that: the high-temperature firing described in the step (e), be that heating rate with 1～20 ℃/min is warmed up to 400～800 ℃, insulation 2～20h, and then be warmed up to 800～1100 ℃ with the heating rate of 1～20 ℃/min, insulation 4～40h.

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