DOUBLE LAYER-COATED NANO-SILICON NEGATIVE ELECTRODE MATERIAL, A METHOD FOR PREPARING THE SAME AND USE THEREOF

This invention relates to a double layer composite-coated nano-silicon negative electrode material, and its preparation methods and use, the negative electrode material comprising: a silicon-based nanoparticle, a copper layer coated on the surface of the silicon-based nanoparticle, and a conductive protective layer coated on the surface of the copper layer. Nano-copper has superplastic ductility and conductivity, and the prior art has proved that lithium ions can penetrate nano-copper; therefore, the copper coating layer has effects of inhibiting the volume expansion of the silicon-based nanoparticle and keeping the silicon-based nanoparticle from cracking so that direct contact between the silicon-based nanoparticle and an electrolyte is effectively avoided and a stable SEI is formed, and increasing the conductivity of the electrode. The surface of the nano-copper is coated with a further conductive protective layer to effectively inhibit the oxidation of the nano-copper, thereby improving the electrochemical performance.