Conductive polymer coated red phosphorus/graphite composite structure negative electrode material and preparation method thereof

Abstract

The invention discloses a conductive polymer-coated red phosphorus / graphite composite structure negative electrode material and a preparation method thereof. The conductive polymer-coated red phosphorus fundamentally and effectively avoids performance deterioration caused by water absorption of red phosphorus; conductive glue plays a role of an adhesive; graphite particles are dispersed among thered phosphorus particles microcosmically, so that the red phosphorus and the graphite are microcosmically and effectively bonded; and therefore, the volume change of the red phosphorus in a charging / discharging process is buffered. The preparation method is simple and easy to operate. The gram volume of the conductive polymer-coated red phosphorus / graphite composite structure negative electrode material prepared by the method is 800mAh / g or above; the lithium intercalation / deintercalation potential of the negative electrode material is 0.8 V; and the negative electrode material can effectivelyavoid safety accidents such as lithium precipitation and the like; and the rate capability of the conductive polymer-coated red phosphorus / graphite composite structure negative electrode material isexcellent, so that the requirement of rapid charging of a lithium ion battery in a short time can be met.

Description

technical field [0001] The invention belongs to the technical field of electrode material preparation, and in particular relates to a red phosphorus / graphite composite negative electrode material coated with a conductive polymer and a preparation method thereof. Background technique [0002] Lithium-ion battery-powered electric vehicles are the general trend to replace fuel vehicles, but the low mileage of electric vehicles, long charging time, and potential safety hazards are the main reasons that hinder consumers' acceptance and purchase. However, the mainstream negative electrode material of lithium-ion batteries is graphite. Its too low theoretical capacity (375mAh / g) and low lithium-ion diffusion coefficient greatly limit the range and charging time of electric vehicles, and its lithium-intercalation voltage value is close to zero. The essential cause of the safety problems caused by the lithium-ion battery decomposing lithium. Red phosphorus elemental phosphorus is ex...

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Problems solved by technology

[0003] The common solid-phase method is to roll red phosphorus into the carbon structure by ball milling, but the obtained conductive polymer-coated red phosphorus / graphite composite structure anode material still has a certain degree of water absorption due to the exposed red phosphorus. It brings a lot of inconvenience to subsequent applications, such as electrode coating, electrode cutting, etc., and the battery performance of the red phosphorus anode material is deteriorated due to the side reaction of the exposed part of the red phosphorus; another common solid-phase method is to heat the red phosphorus to sublimation, and then condensed to achieve the effect of compounding with graphite, but in the heating process, red phosphorus is first transformed into white phosphorus, so the prepared red phosphorus negative electrode product also contains white phosphorus, and white phosphorus is a toxic substance, so the red phosphorus negative electrode obtained by this method Due to white phosphorus pollution, there are potential safety hazards and cannot be applied industrially

The liquid phase method mostly prepares red phosphorus / graphene composites by loading red phosphorus on graphene or incomplete coating, but it still cannot avoid the water absorption characteristics of red phosphorus in the composite, and this method involves the preparation of graphene or Use, the process is cumbersome and expensive, and the cost performance is low

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