High-temperature solid-phase synthesis method of one-dimensional nano-sodion cell anode material NaxMnO2

Abstract

The invention discloses a high-temperature solid-phase synthesis method of a one-dimensional nano-sodion cell anode material NaxMnO2. The high-temperature solid-phase synthesis method comprises the following steps of 1, dissolving a sodium salt and a manganese salt in water according to a mole ratio of sodium to manganese of 0.44-0.56 to obtain a solution I, 2, dissolving citric acid in water to obtain a solution II, wherein a mole ratio of citric acid to the total metal ions is in a range 0.5-1, 3, dropwisely adding the solution I into the solution II and carrying out stirring for 10-60min, 4, carrying out heating evaporation on the mixed solution at a temperature of 60-90 DEG C to remove a solvent, heating the residues at a temperature of 120 DEG C for 6-24h, cooling the heated residues to a temperature of 10-30 DEG C, and grinding the cooled residues into powder, 5, heating the powder at a temperature of 350-500 DEG C for 3-10h, cooling the powder to a temperature of 10-30 DEG C, and grinding the cooled powder into fine powder, and 6, heating the fine powder at a temperature of 800-950 DEG C for 10-45h, and carrying out cooling to obtain the one-dimensional nano-sodion cell anode material NaxMnO2. The high-temperature solid-phase synthesis method has short synthesis time and a high yield in unit time. The one-dimensional nano-sodion cell anode material NaxMnO2 has uniform, dispersive, thin and long product morphology and good electrochemical properties (of a specific discharge capacity of 114mA.h / g at 0.1C charging-discharging multiplying power).

Description

technical field [0001] The invention belongs to the field of battery materials, and in particular relates to a method for synthesizing battery anode materials. Background technique [0002] There are many similarities between Na-ion and Li-ion batteries, and Na-ion batteries have some distinct advantages over Li-ion batteries, such as low raw material costs and the use of electrolyte systems with lower decomposition potentials. So far, the main cathode materials for sodium-ion batteries are NaVPO 4 F. Na x CoO 2 、Na x MnO 2 Layered crystalline compounds and their doped compounds. [0003] Na x MnO 2 The preparation methods of materials mainly include solid phase method, hydrothermal method, sol-gel method and so on. Among them, the manganese source mainly used in the solid phase method is MnCO 3 and Mn 2 o 3 , the sodium source is Na 2 CO 3 , the reaction temperature is 800-900°C, and the reaction time is less than 12h, but the morphology of the products all pre...

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Problems solved by technology

Among them, the manganese source mainly used in the solid phase method is MnCO 3 and Mn 2 o 3 , the sodium source is Na 2 CO 3 , the reaction temperature is 800-900°C, and the reaction time is less than 12h, but the morphology of the products all presents an uneven thick rod-like structure and is bonded to each other. The particles are too large, which is likely to cause poor contact between particles and diffusion of sodium ions. The distance increases, and at a charge-discharge rate of 0.1C, the discharge specific capacity of the product is only 80mA·h / g, and the discharge specific capacity after adding carbon nanotubes is only 113mA·h / g

And the hydrothermal method, when the reaction temperature is above 200°C and the reaction time is 72 hours, sodium manganese oxygen nanowires can be obtained and have good electrochemical properties, but the reaction time of 72 hours is too long, the output per unit time is low, and the amount of sodium consumed Larger (sodium-manganese ratio is generally greater than 150), not suitable for large-scale industrial production. In addition, the manganese source Mn used in the hydrothermal method 2 o 3 and Mn 3 o 4 It also needs to be in the form of fine particles, otherwise it is difficult to obtain nanowires even after 72 hours of reaction

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