Lithium titanate-carbon composite nano-material, preparation method thereof and application thereof

Abstract

The invention discloses a lithium titanate-carbon composite nano-material, a preparation method thereof and application thereof. The method comprises the following steps: 1) statically spinning lithium titanate sol, or lithium titanate sol doped with a conductive substance or lithium titanate sol doped with metal ions to obtain a thin film, wherein the conductive substance is conductive metal or conductive carbon; and 2) heat treating the thin film in inert atmosphere to obtain the lithium titanate-carbon composite nano-material. The lithium titanate-carbon composite nano-material provided by the invention has a standard one-dimensional morphological structure, high crystallinity, high conductivity and high safety performance, and has high lithium ion diffusion speed and high electronic conductivity when applied as the cathode material of the lithium ion battery. Moreover, the lithium titanate-carbon composite nano-material has high charge / discharge capacity, excellent high-current charge / discharge performance and stable cycling performance. The 10c charge / discharge capacity is 125mAh / g, the 40C charge / discharge capacity reaches 95mAh / g, and the retention rate of the high-current 40C charge / discharge capacity within 3000 times reaches 85 percent.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries in a non-aqueous electrolyte system, in particular to a lithium titanate-carbon composite nanomaterial and a preparation method and application thereof. Background technique [0002] At present, commercial lithium-ion battery anode materials generally use carbon anode materials, but there are two prominent shortcomings in carbon anode materials: 1. The oxidation-reduction potential of carbon electrodes is different from that of Li + The electrode potentials of / Li are very close. When the battery is overcharged, lithium ions precipitate on the surface of the carbon electrode to form lithium dendrites, which may cause a short circuit in the battery and cause safety problems. 2. The carbon negative electrode material reacts with the non-aqueous electrolyte to form a solution interface solid electrolyte film (SEI film), which increases the capacity decay of the lithium-ion battery and reduces th...

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Problems solved by technology

[0002] At present, commercial lithium-ion battery anode materials generally use carbon anode materials, but there are two prominent shortcomings in carbon anode materials: 1. The oxidation-reduction potential of carbon electrodes is different from that of Li + The electrode potential of / Li is very close to

When the battery is overcharged, lithium ions precipitate on the surface of the carbon electrode to form lithium dendrites, which may cause a short circuit in the battery and cause safety problems

2. The carbon negative electrode material reacts with the non-aqueous electrolyte to form a solution interface solid electrolyte film (SEI film), which increases the capacity decay of the lithium-ion battery and reduces the rate discharge capacity

However, these modification methods are modified by introducing a conductive phase outside the lithium titanate particles, which is difficult to form a uniformly coated continuous conductive network, and the process is complicated and cumbersome.

[0009] At present, there is no report that comprehensively utilizes the advantages of material nanotechnology and modification technology to synthesize Li in situ. 4 Ti 5 o 12 @C nanowire composite material

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