Micro-sphere compound anode material with core-shell structure and preparation method thereof

Abstract

The invention discloses a micro-sphere compound anode material with a core-shell structure and a preparation method thereof. The compound anode material is a compound micro-sphere with the core-shell structure; the material of the core is a silicon micro-sphere; and the material of the shell layer is formed by uniformly embedding Li1+xV1-xO2 and oxide cathode or metal anode materials in amorphousporous carbon. The preparation method of the compound anode material comprises the following steps of dissolving a lithium source and a vanadium source in deionized water at a constant temperature; adding macromolecule glue and uniformly dispersing by adopting ultrasonic wave; slowly adding in the glue state phase when dispersing the silicon micro-sphere and the oxide cathode or the metal anode material by adopting the ultrasonic wave; and then sequentially carbonizing and combining in the inertia or reducing atmosphere to obtain the core-shell structured compound micro-sphere taking the silicon micro-sphere as the core and the porous amorphous carbon as the shell. The discharging ratio capacity is more than 980mA h / g when the compound micro-sphere material is used at the cathode of the lithium ion battery. And the charging and discharging efficiency at the first time is more than 85%; the capacity conservation rate is more than 92% after the micro-sphere compound anode material is recycled for 500 times.

Description

technical field [0001] The invention relates to a microsphere composite negative electrode material with a core-shell structure and a preparation method thereof, in particular to a core-shell structure composite microsphere negative electrode material for lithium ion secondary batteries or power energy sources and a preparation method thereof. Background technique [0002] At present, the lack of energy in the world and the deterioration of the environment have promoted the development and utilization of green and environmentally friendly new energy with excellent performance and low price. The development and utilization of energy materials has become an urgent issue in today's society. Under this premise, lithium-ion batteries have quickly become a research and development hotspot due to their environmental friendliness, high working voltage, high specific energy, and long cycle life. The government's strong support policies for the development of electric vehicles and the...

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Problems solved by technology

However, pure silicon is accompanied by a volume expansion effect of up to 3 times during the deintercalation process, which produces a large mechanical stress, which leads to the gradual powdering and falling off of the electrode material, and the conductive network in the electrode material is gradually interrupted. Therefore, the cycle performance of the electrode material poor

At present, the research on the modification of silicon-based electrode materials mainly includes the use of chemical vapor deposition to deposit amorphous carbon on silicon materials to form silicon-coated materials; the use of mechanical ball milling to mechanically mix silicon and graphite to form binary composite materials. These methods The structure of the obtained composite material is not ideal, mostly a simple mixture of carbon and silicon materials, even if the coating is achieved, the coating effect is poor, and the proportion of silicon in the composite material is small, so the specific capacity of the composite material It is also small, and the electrochemical cycle performance has not met the ideal requirements.

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