Preparation method of tin-silicon-based graphne ball negative electrode material for lithium ion battery

Abstract

The invention discloses a preparation method of a tin-silicon-based graphene ball negative electrode material for a lithium ion battery. The preparation method comprises the following steps that (1) asilicon ester monomer is dissolved in an organic solvent and prepared to be a mixed solution A, a dry stannic oxide ball with the diameter being 15-25nm is taken for stand-by application; (2) the mixed solution A and the stannic oxide ball are uniformly mixed at the stoichiometric ratio, the mixture is dried at the temperature of 30-70 DEG C, and a stannic oxide composite material is obtained; (3) the stannic oxide composite material is roasted in a maffle furnace, and a stannic oxide nano ball wrapped with silicon dioxide is obtained; and (4) the stannic oxide nano ball is placed in a tubular atmosphere furnace, the tubular atmosphere furnace is filled with carrier gas and carbon source gas, and the tin-silicon graphene ball wrapped with graphene is prepared by utilizing chemical vapor deposition. The prepared tin-silicon graphene ball is firm, binding problem between graphene and a to-be-wrapped material is avoided, meanwhile, graphene can completely and uniformly wrap SnO2 nano particles, graphene forms a good buffer layer and an electricity conductive network to SnO2, the capacity can reach 600-1500mAh / g, and the coulombic efficiency can reach 80-98%.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a preparation method of a tin-silicon-based graphene ball negative electrode material for lithium ion batteries. Background technique [0002] As a new generation of green high-energy batteries, lithium-ion batteries have the advantages of small weight, high energy density, long cycle life, high working voltage, no memory effect, and no environmental pollution. They have been widely used in portable electronics such as mobile phones, notebook computers, and cameras. Among the equipment, it is also the preferred power source for electric vehicles and hybrid electric vehicles in the future, and has broad application prospects. [0003] Anode materials are one of the key components of lithium-ion batteries. At present, graphite anode materials account for more than 98% of the global lithium battery anode materials. However, during the charging and discharging proce...

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Problems solved by technology

[0005] Yang Quanhong's research group used graphene to coat tin dioxide nanoparticles to prepare SnO 2 Nanoparticles / graphene composite anode material (ACS Nano, 2009, 3(11): 3730-3736), exhibited good electrochemical properties, with a specific capacity as high as 840mAh / g, however, since graphene cannot completely convert SnO 2 The uniform coating of nanoparticles also results in extremely poor cycle performance of the material

In addition, since graphene and SnO 2 Nanoparticles are not in good contact, and the rate performance of the prepared materials needs to be improved urgently

Zhang et al. prepared SnO by hydrothermal method 2 Nanoparticles / graphene composite anode materials (JMC, 2011, 21(6): 1673-1676), also show high specific capacity, but the cycle stability is still not good

The reason is that the added graphene is simply mixed with nano-tin dioxide through van der Waals force, and the contact between the two is poor, and there is no effect on the SnO. 2 Forms a very good buffer layer and conductive network

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