Negative pole active material for silicon-based lithium ion battery and preparation and application thereof

Abstract

The invention provides a negative pole active material for a silicon-based lithium ion battery and preparation and application thereof. The negative pole active material of the silicon-based lithium ion battery comprises porous reduced graphite oxide and a porous silicon material coated with conductive polymerization attached to the pores of the porous reduced graphite oxide; the porous reduced graphite oxide has a pore diameter of 50 nanometres-2 micrometers; a conductive polymer coating layer has a thickness of 50 nanometres-200 micrometers; the porous silicon has a pore diameter of 100 nanometres-300 nanometres. The conductive polymer is one or more of polyaniline, polypyrrole and polythiophene. When the material is applied to a negative pole of the lithium ion battery, the material hasthe significant advantages of difficult pulverization, good stability, a large number of cycles and the like.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery negative electrode active material and a preparation method thereof. Background technique [0002] A lithium-ion battery is a rechargeable battery that relies on lithium ions to move between the positive and negative electrodes during charging and discharging to complete the work. The application of lithium-ion batteries in energy storage fields such as portable electronic devices and power vehicles is becoming more and more popular. The development of lithium-ion batteries with higher energy density and power density has become an important research direction in today's energy storage technology work. The further development of lithium-ion batteries depends largely on the capacity of negative electrode materials and the substantial improvement in high-rate and high-current discharge performance. At present, the bottleneck of the t...

AI Technical Summary

Problems solved by technology

[0003] Although silicon-based negative electrode materials have high theoretical discharge capacity and low lithium intercalation potential, they have low electrical conductivity (10 -3 S / cm) and the low diffusion coefficient of lithium ions in bulk silicon (10 -14 ~10 -13 cm 2 / s) Disadvantages

The main reason for the decline in its cycle performance is that the volume of silicon expands up to 300% during the process of lithium intercalation, shrinks during the delithiation process, and then the material is pulverized, the material loses electrical contact with the current collector, and the exposed silicon surface is in contact with the current collector. LiPF in electrolyte 6 The HF produced by the decomposition reacts, making it impossible to form a stable cabinet electrolyte film on the silicon surface, and continuously consumes the electrolyte, resulting in poor cycle stability and cycle performance of the battery

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