Silicon-carbon nanotube microspheres and metal lithium compound thereof, and preparation method and application

Abstract

The invention discloses silicon-carbon nanotube microspheres and a metal lithium compound thereof, and a preparation method and an application. The silicon-carbon nanotube microspheres comprise carbon nanotube microspheres and silicon distributed on the surfaces and in the pore spaces of the carbon nanotube microspheres; the carbon nanotube microspheres have a self-supporting framework structure formed by carbon nanotubes in a mutual intertwining and agglomeration manner; and the metal lithium compound, namely metal lithium-silicon-carbon nanotube composite microspheres comprise the silicon-carbon nanotube microspheres and metal lithium distributed on the surfaces and in the pore spaces of the silicon-carbon nanotube microspheres, wherein the metal lithium and silicon exist in an elementary substance state. By virtue of the metal lithium-silicon-carbon nanotube composite microspheres provided by the invention, the cycling stability, coulombic efficiency and safety of a battery can be effectively improved; and meanwhile, the preparation method is simple and batch production can be realized.

Description

technical field [0001] The invention relates to a nanocomposite material, in particular to a silicon-carbon nanotube microsphere, a metal lithium-silicon-carbon nanotube composite microsphere and a preparation method and application thereof, belonging to the field of lithium-ion battery negative electrodes. Background technique [0002] Lithium metal, as one of the electrode materials with the highest mass-to-energy ratio, has the advantages of low electrode potential, high exchange current density, and small polarization, and has always attracted the attention of researchers. However, metal lithium is easy to form dendrites during charging and discharging, resulting in reduced battery capacity, poor cycle performance, and possible safety issues such as fire, which is an important reason restricting the research and application of lithium-ion batteries. Lithium-ion batteries with carbon materials as negative electrodes are widely used because of their relatively high cycle l...

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Problems solved by technology

Patent CN 101162772A adopts the direct electrochemical deposition method to deposit a layer of metal lithium on the foam substrate to prepare a foam metal lithium negative electrode with a high specific surface area. Dendrites grow in the foam structure, which can reduce the occurrence of short circuits, but the battery cycle stability is poor

Patent CN 104064732A prepares an electrolyte containing silicon salt and lithium salt, and deposits a layer of lithium-silicon film on the metal current collector by pulse electrodeposition method, which improves the cycle stability of the battery, but the preparation process is relatively complicated

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