Method for synthesizing MnFe-based sodium ion battery positive electrode material from waste lithium manganate battery positive electrode material

Abstract

The invention belongs to the field of resource recycling, and particularly relates to a method for synthesizing a MnFe-based sodium ion battery positive electrode material from a waste lithium manganate battery positive electrode material. The waste lithium manganate battery is discharged, roasted, disassembled and ground to obtain the lithium manganate positive electrode material. Taking FeSO4. 7H2O as a sulfate auxiliary agent, sequentially carrying out sulfating roasting of the positive electrode material, washing of a roasted product, suction filtration and separation to obtain a precursor, and finally calcining to obtain the MnFe-based sodium ion battery positive electrode material. The method provided by the invention has the characteristics of low cost and simple process, combines resource recovery with high-performance material regeneration, and provides a sustainable solution for recovery of waste lithium manganate batteries.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of resource recycling, and more particularly relates to a method for synthesizing MnFe-based sodium ion battery cathode material from waste lithium manganate battery cathode material. BACKGROUND

[0002] With the rapid development of new energy industry and the continuous improvement of economic level, efficient energy storage and conversion technology has become the key to promoting sustainable development. Lithium ion batteries, as efficient and clean energy storage materials, are widely used in new energy vehicles, portable electronic devices, large-scale energy storage systems and other fields. However, with the explosive growth of demand for lithium ion batteries, the shortage of lithium resources and the problem of recycling of waste lithium ion batteries have become increasingly prominent. Lithium manganate (LiMn2O4) batteries have a large market share in computers, communications and consumer electronics due to their low cost, and therefore a large number of waste lithium manganate batteries cannot be disposed of. It is worth noting that converting valuable metals from waste lithium ion batteries into new energy storage materials can alleviate resource shortages and achieve recycling of waste lithium ion batteries. For example, CN115411392B discloses a method for recycling and reusing waste lithium manganate cathode material. Specifically, waste lithium manganate is used as raw material, and after lithium removal treatment, a manganese-based material for reuse is obtained, which is compounded with a nickel-based material and modified by an additive, and finally used as a positive active material for alkaline secondary batteries.

[0003] In recent years, sodium ion batteries (SIBs) have been considered as an ideal supplement to lithium ion batteries due to their abundant resources, low cost, and similar "rocking chair" type electrochemical mechanism as lithium ion batteries. Recycling waste lithium manganate cathode material and regenerating sodium ion battery cathode material have good value for resources and the environment.

[0004] The present application is based on economic cost, green environmental protection and resource utilization. FeSO4·7H2O is used as a sulfate auxiliary agent, and selective separation of lithium is achieved by sulfuric acid roasting combined with water leaching. The leaching residue, sodium salt and TiO2 are mixed and roasted to realize one-step synthesis of MnFe-based sodium ion battery cathode material. This route has the characteristics of low cost, greenness and short process, and provides a new path for recycling and reusing waste lithium ion batteries. SUMMARY

[0005] In view of the recycling and disposal of retired lithium manganate batteries, the present application aims to provide a method for synthesizing MnFe-based sodium ion battery cathode material from waste lithium manganate battery cathode material.

[0006] To achieve the above-mentioned purpose, the present application provides a method for synthesizing MnFe-based sodium ion battery cathode material from waste lithium manganate battery cathode material, comprising the following steps: Step S1, discharging, calcining, and disassembling waste lithium manganese oxide batteries to obtain lithium manganese oxide positive electrode materials; Step S2, FeSO4·7H2O and the disassembled lithium manganate positive electrode material are uniformly mixed at a molar ratio of 0.3-2, heated to 800-1000°C and calcined for 2-6 hours, and then cooled in the furnace to obtain a calcined product; Step S3: the calcined product is heated to a liquid-solid ratio of 20-40 mL·g -1 Place in deionized water and react at 25°C for 30-60 minutes, and separate the leaching solution containing lithium and the leaching residue containing manganese and iron by vacuum filtration; Step S4, mixing the leached residue containing manganese and iron elements with TiO2 and sodium salt to obtain a mixed powder containing sodium, manganese, iron and titanium elements; Step S5: heating the mixed powder containing sodium, manganese, iron, and titanium elements to 950-1100° C. and calcining for 6-10 h, followed by cooling in the furnace to obtain a MnFe-based sodium ion battery positive electrode material.

[0007] Furthermore, the sodium salt in step S4 includes but is not limited to sodium carbonate, sodium bicarbonate, sodium sulfate, and sodium chloride.

[0008] Furthermore, the MnFe-based sodium ion battery cathode material in step S5 is Na 0.78 Mn x Fe y Ti 1-x-y O2(0.7 <x≤0.9,0.1<y≤0.3)。

[0009] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The present invention provides a new method for recycling and reusing the positive electrode material of waste lithium manganese oxide batteries. The regenerated MnFe-based sodium ion battery positive electrode material exhibits good battery capacity and cycle stability. (2) The present invention provides a low-cost, green, and short-process process route for the recycling and reuse of waste lithium manganese oxide battery positive electrode materials, providing a new path for the recycling and reuse of waste lithium manganese oxide batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a process flow chart of the present invention Figure 2 This is the XRD pattern of the prepared MnFe-based sodium ion battery positive electrode material DETAILED DESCRIPTION

[0011] The present invention is described in detail below with reference to the embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0012] Example 1 (1) After discharging, calcining, disassembling and grinding, lithium manganese oxide positive electrode material was obtained. 0.77 g of FeSO4·7H2O and 1 g of the disassembled lithium manganese oxide positive electrode material were mixed evenly, heated to 1000°C and calcined for 2 h, and then cooled in the furnace to obtain a calcined product; (2) The calcined product was heated to a liquid-solid ratio of 20 mL·g -1 Place in deionized water, react at 25°C for 30 min, and separate the leachate containing lithium and the leach residue containing manganese and iron by vacuum filtration; (3) 0.755 g of leached residue containing manganese and iron elements was mixed evenly with 0.02 g of TiO2 and 0.44 g of Na2CO3 and heated at 5 °C·min -1 The temperature was raised to 950℃ and calcined for 10 h. After cooling in the furnace, the MnFe-based sodium ion battery cathode material was obtained. The MnFe-based sodium ion battery cathode material was calculated by ICP analysis. 0.78 Mn 0.774 Fe 0.199 Ti 0.027 O2.

[0013] (4) 0.02 g of MnFe-based sodium ion battery positive electrode material, 0.0057 g of acetylene black and 0.0029 g of polyvinylidene fluoride were mixed evenly, and N-methyl-2-pyrrolidone was added dropwise to make a honey-like slurry, which was evenly coated on aluminum foil. The mixture was vacuum-dried at 120 °C for 12 h and cut into discs with a diameter of 14 mm after drying. The CR2032 button cells were assembled in an argon atmosphere glove box, with the sodium sheet and glass cellulose membrane as the anode and separator, respectively. The obtained MnFe-based sodium ion battery was tested at 200 mA·g -1 At a current density of 96.0 mAh·g -1 The discharge capacity remains at 88.6 mAh g after 150 cycles. -1 discharge capacity.

[0014] Example 2 (1) After discharging, calcining, disassembling and grinding, lithium manganate positive electrode material was obtained. 0.77 g FeSO4·7H2O and 1 g disassembled lithium manganate positive electrode material were mixed evenly and heated at 10 ℃·min -1 The temperature was raised to 800℃ and calcined for 6 h, and then cooled in the furnace to obtain the calcined product. (2) The calcined product was heated to a liquid-solid ratio of 40 mL·g -1 The mixture was placed in deionized water and reacted at 25°C for 60 min. The leaching solution containing lithium and the leaching residue containing manganese and iron were separated by vacuum filtration. (3) 0.755 g of leached residue containing manganese and iron elements was mixed evenly with 0.59 g of Na2SO4 and heated at 5 °C·min -1 The heating rate was increased to 1000℃ and calcined for 6 h. After cooling in the furnace, the MnFe-based sodium ion battery cathode material was obtained. The ICP analysis showed that the MnFe-based sodium ion battery cathode material was Na 0.78 Mn 0.795 Fe 0.205 O2.

[0015] (4) 0.02 g of MnFe-based sodium ion battery positive electrode material, 0.0057 g of acetylene black and 0.0029 g of polyvinylidene fluoride were mixed evenly, and N-methyl-2-pyrrolidone was added dropwise to make a honey-like slurry, which was evenly coated on aluminum foil. The mixture was vacuum-dried at 120 °C for 12 h and cut into discs with a diameter of 14 mm after drying. The CR2032 button cells were assembled in an argon atmosphere glove box, with the sodium sheet and glass cellulose membrane as the anode and separator, respectively. The obtained MnFe-based sodium ion battery was tested at 200 mA·g -1 At a current density of 98.2 mAh·g -1 The discharge capacity of the battery remained at 76.8 mAh g after 150 cycles. -1 discharge capacity.

[0016] Example 3 (1) After discharging, calcining, disassembling and grinding, lithium manganate positive electrode material was obtained. 0.77 g FeSO4·7H2O and 1 g disassembled lithium manganate positive electrode material were mixed evenly and heated at 10 ℃·min -1 The temperature was raised to 800℃ and calcined for 6 h, and then cooled in the furnace to obtain the calcined product. (2) The calcined product was heated to a liquid-solid ratio of 30 mL g -1 Place in deionized water, react at 25°C for 30 min, and separate the leachate containing lithium and the leach residue containing manganese and iron by vacuum filtration; (3) 0.755 g of leached residue containing manganese and iron elements was mixed evenly with 0.008 g of TiO2 and 0.706 g of NaHCO3 and heated at 10 °C·min -1 The temperature was raised to 800℃ and calcined for 10 h. After cooling in the furnace, the MnFe-based sodium ion battery cathode material was obtained. The MnFe-based sodium ion battery cathode material was calculated by ICP analysis. 0.78 Mn 0.788 Fe 0.202 Ti 0.010 O2.

[0017] (4) 0.02 g of MnFe-based sodium ion battery cathode material, 0.0057 g of acetylene black and 0.0029 g of polyvinylidene fluoride were mixed evenly, and N-methyl-2-pyrrolidone was added dropwise to make a honey-like slurry, which was evenly coated on aluminum foil. The mixture was vacuum-dried at 120 °C for 12 h and cut into discs with a diameter of 14 mm after drying. The obtained MnFe-based sodium ion battery was -1 At a current density of 96.4 mAh·g -1 The discharge capacity of the battery remained at 81.9 mAh g after 150 cycles. -1 discharge capacity.

[0018] Example 4 (1) After discharging, calcining, disassembling and grinding, lithium manganate positive electrode material was obtained. 0.77 g FeSO4·7H2O and 1 g disassembled lithium manganate positive electrode material were mixed evenly and heated at 5 ℃·min -1 The temperature was raised to 900℃ and calcined for 2 h, and then cooled in the furnace to obtain the calcined product. (2) The calcined product was heated to a liquid-solid ratio of 20 mL·g -1 Place in deionized water, react at 25°C for 30 min, and separate the leachate containing lithium and the leach residue containing manganese and iron by vacuum filtration; (3) 0.755 g of leached residue containing manganese and iron elements was mixed evenly with 0.004 g of TiO2 and 0.491 g of NaCl and heated at 5 °C·min -1 The temperature was raised to 950℃ and calcined for 10 h. After cooling in the furnace, the MnFe-based sodium ion battery cathode material was obtained. The specific content of the MnFe-based sodium ion battery cathode material was Na 0.78 Mn 0.758 Fe 0.190 Ti 0.052 O2.

[0019] (4) 0.02 g of MnFe-based sodium ion battery positive electrode material, 0.0057 g of acetylene black and 0.0029 g of polyvinylidene fluoride were mixed evenly, and N-methyl-2-pyrrolidone was added dropwise to make a honey-like slurry, which was evenly coated on aluminum foil. The mixture was vacuum-dried at 120 °C for 12 h and cut into discs with a diameter of 14 mm after drying. The CR2032 button cells were assembled in an argon atmosphere glove box, with the sodium sheet and glass cellulose membrane as the anode and separator, respectively. The obtained MnFe-based sodium ion battery was tested at 200 mA·g -1 At a current density of 86.3 mAh·g -1 The discharge capacity of the battery remained at 81.6 mAh g after 150 cycles. -1The discharge specific capacity of the battery was 1, 200 mAh / g

Claims

1. A method for synthesizing MnFe-based sodium ion battery positive electrode materials from waste lithium manganese oxide battery positive electrode materials, characterized in that: The steps include: (1) discharging, roasting, and disassembling waste lithium manganese oxide batteries to obtain lithium manganese oxide positive electrode materials, and then adding FeSO4·7H2O sulfate auxiliary agent to the positive electrode materials for sulfated roasting to obtain a mixed powder containing lithium, manganese, and iron elements; (2) adding the mixed powder containing lithium, manganese and iron elements obtained in step (1) into deionized water for water leaching to selectively extract lithium, and filtering to obtain a leachate containing lithium elements and a leach residue containing manganese and iron elements; (3) adding TiO2 and sodium salt to the leaching residue containing manganese and iron elements obtained in step (2) to obtain a mixed powder containing sodium, manganese, iron and titanium elements; (4) The mixed powder containing sodium, manganese, iron and titanium elements obtained in step (3) is calcined at high temperature to obtain MnFe-based sodium ion battery positive electrode material Na 0.78 Mn x Fe y Ti 1-x-y O2 (0.7 <x≤0.9,0.1<y≤0.3)。 2. The method according to claim 1, wherein In step (1), during the sulfate calcination process, the molar ratio of FeSO4·7H2O to the positive electrode material is 0.3-2, the sulfate calcination reaction temperature is 800-1000°C, and the sulfate calcination reaction time is 2-6 h.

3. The method according to claim 1, wherein In step (2), during the water immersion process, the liquid-to-solid ratio of deionized water to the calcined product is 20-40 mL·g -1 The water immersion reaction temperature is 25℃, and the water immersion reaction time is 30~60 min.

4. The method according to claim 1, wherein in step (3), the sodium salt includes but is not limited to sodium carbonate, sodium bicarbonate, sodium sulfate, and sodium chloride.

5. The method according to claim 1, wherein In step (4), during the high-temperature calcination process, the high-temperature calcination reaction temperature is 800-1000° C., and the high-temperature calcination reaction time is 6-10 h.

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