Stannic phosphide/graphene composite cathode material for sodium-ion battery and preparation method thereof

Abstract

The invention discloses a stannic phosphide / graphene composite cathode material for a sodium-ion battery and a preparation method thereof. The composite cathode material is a three-dimensional structure material formed by wrapping the surfaces of nano stannic phosphide particles with flake graphite. The preparation method comprises the steps of adding metal tin powder, phosphorus powder and grinding balls into a ball milling jar of a high-energy ball milling machine, performing chemical reaction while ball milling under the protection of inert gas or nitrogen atmosphere to obtain the nano stannic phosphide particles, then adding graphene dispersion liquid into the ball milling jar, further performing ball milling to enable the surfaces of the nano stannic phosphide particles to be evenly wrapped by the graphene, and arranging a ball milling product in an inert gas or nitrogen protection environment to perform heat processing so as to obtain the stannic phosphide / graphene composite cathode material. A testing result shows that the composite cathode material has very high charging-discharging specific capacity and stable circulating performance after the composite material serving as the cathode material for the sodium-ion battery is prepared into a half battery. The preparation method of the composite material is simple, reliable and good in process repeatability and in operability, is environmentally friendly and is suitable for industrial production.

Description

technical field [0001] The invention relates to a tin phosphide / graphene negative electrode composite material for sodium ion batteries and a preparation method thereof, belonging to the field of sodium ion batteries. Background technique [0002] Lithium-ion batteries are currently the dominant electrochemical energy storage system. With the rapid popularization of mobile devices such as personal computers, cameras, and mobile phones, and their good application prospects in electric vehicles and hybrid vehicles, the demand for lithium-ion batteries continues to increase. increase. However, rising lithium prices and limited reserves have become bottlenecks in mass production and large-scale commercialization. Sodium-ion batteries have attracted extensive attention due to their rich reserves of sodium resources and low cost. The research and development of sodium-ion batteries can alleviate the limited development of batteries caused by the shortage of lithium resources to a...

AI Technical Summary

Problems solved by technology

[0003] The research results show that tin (847mAh g -1 ) and phosphorus (2596mAh g -1 ) have high sodium storage capacity, and its compound tin phosphide can electrochemically react with sodium to generate Na 15 sn 4 and Na 3 P, so tin phosphide has a very high volume specific capacity (6650mAh cm -3 ), but due to its own low electronic / ionic conductivity and serious volume expansion in the process of deintercalating sodium, its cycle stability is extremely low, resulting in its application being limited, so how to improve the cycle stability of tin phosphide, It has become the key to the research of tin phosphide as a negative electrode material for sodium ion batteries

At present, there is no effective method to slow down the rapid loss of the capacity of tin phosphide due to the volume expansion in the process of intercalating sodium.

So far, there is no technology to effectively combine graphene and tin phosphide to prepare composite materials, and there is no relevant report on related composite materials as anode materials for sodium batteries.

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