Method for manufacturing transition metal oxide/carbon nanotube composite and the resulting composite

Anode composite with oxide nanoparticles grown on CNT surfaces via microwave selective heating without acid treatment

This technology enables the selective heterogeneous nucleation and growth of transition metal oxide nanoparticles from transition metal salts in solution onto carbon nanotube (CNT) surfaces using microwave irradiation, eliminating the need for acid treatment. It leverages the principle that free electrons in CNTs absorb microwave energy to induce localized high-temperature heating, allowing for uniform nanoparticle deposition.

Conventional manufacturing of transition metal oxide/CNT composites requires acid treatment of the CNT surface, which increases processing time and costs while damaging the CNT structure. Furthermore, the spinel-structured Li4Ti5O12 is difficult to synthesize at the nanoscale and has low conductivity, limiting its high-rate charge/discharge performance and capacity.

This technology uses a microwave synthesis device to heat materials at 2.45–60 GHz for 10–30 minutes, uniformly forming 2–30 nm Fe3O4, TiO2, or Li4Ti5O12 nanoparticles on CNT surfaces without acid treatment. Li4Ti5O12 is heat-treated at 500–900°C in a hydrogen-argon atmosphere to stabilize its spinel structure. Applicable to high-power hybrid vehicle batteries, fast-charging LTO anodes, and lithium-ion capacitor electrodes, this rapid, minutes-long synthesis process significantly reduces mass production costs.

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Key Features:

• Adding carbon nanotube powder to a solvent and dispersing it uniformly using methods such as ultrasonication
• Mixing a transition metal salt, selected from iron or titanium salts, into the solvent containing the dispersed carbon nanotubes to form a mixed solution
• Applying microwaves to the mixed solution to form transition metal oxide nanoparticles on the carbon nanotube surfaces, synthesizing Fe3O4/CNT or TiO2/CNT composites
• Li4Ti5O12/carbon nanotube composite with spinel-structured lithium titanium oxide deposited as nano-sized particles on the carbon nanotube surfaces

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