Method for manufacturing an anode active material for a sodium-ion secondary battery, an anode active material for a sodium-ion secondary battery manufactured thereby, and a sodium-ion secondary battery comprising the same

High-Tap Density Sodium-Ion Battery Anode Material Based on Carbon-Coated Hydrothermally Synthesized Spherical TiO2 Secondary Particles

This technology involves manufacturing an anode active material by uniformly coating 5–10 wt% of carbon onto the surface of micro-sized spherical titanium dioxide (TiO2) particles, which are composed of aggregated nano-sized primary particles synthesized via a hydrothermal method, thereby enhancing electrical conductivity and sodium-ion reactivity.

Conventional anode materials for sodium-ion batteries have faced limitations due to the large size of sodium ions, which results in slow migration speeds and low reversible capacity. Furthermore, they suffer from rapid capacity degradation and low tap density, leading to poor energy density.

This technology utilizes hydrothermal synthesis with a titanium tetrachloride (TiCl4) precursor, a urea hydrolyzing agent, and a spheroidizing agent to obtain spherical secondary TiO2 particles with easily controllable primary particles. Subsequent sucrose-based heat treatment uniformly coats the surface with carbon, improving both electronic conductivity and tap density (0.8–1.2 g/cm³). It can be applied to sodium-ion battery anodes for low-cost energy storage systems and residential power storage, securing high volumetric storage capacity while reducing material costs.

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Key Features:

• A step of manufacturing micro-sized spherical titanium dioxide secondary particles composed of nano-sized primary particles
• A step of manufacturing a titanium dioxide-carbon composite containing 5 to 10 wt% of carbon using the manufactured titanium dioxide particles
• A step of adding urea and a spheroidizing agent to a titanium precursor solution and performing a hydrothermal reaction at 100 to 150°C for 20 to 30 hours
• A step of mixing the titanium dioxide with a sucrose carbon precursor solution, drying it, and performing heat treatment at 350 to 420°C

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