(1) Detonation cracking method

The detonation cracking method utilizes the properties of graphite that can accommodate foreign negative ion layers to form expandable graphite or lower order GICs, where the ion layer contained is called the insertion layer. In expandable graphite or low order GICs, the insertion layers are regularly arranged in graphite layers. During detonation, the insertion layer rapidly decomposes and releases a large amount of gas, impacting the graphite layers and pushing adjacent graphite layers apart to prepare nano graphite thin sheets. During the detonation process, * * plays two roles simultaneously: firstly, it releases a large amount of heat during the explosion, causing the decomposition of expandable graphite or lower order GICs; The other is to use the shock wave generated during detonation to crush the graphite sheet, achieving the effect of refining the graphite, thereby preparing flake graphite with smaller diameter and very thin thickness.

At present, mainly based on the characteristic that graphite can only form stable low order GICs in strong acid environments, graphite is mixed with strong oxidizing acids to prepare stable GICs. Then, * * components are added and ignited to prepare graphite flakes with a diameter size of micrometers and a thickness distribution of 40-100nm. Moreover, the prepared product has a high degree of graphitization, and the specific surface area can be increased to 7-9 times that of the original graphite.

(2) Ultrasonic crushing method

Ultrasonic crushing of expanded graphite is the use of ultrasonic cavitation to generate local high temperature and high pressure in extremely special physical environments, causing expansion

The graphite layers on the expanded graphite are completely separated, and the expanded graphite is made into completely free nano graphite microsheets. Ultrasonic crushing

During the process of expanding graphite, solvents can easily enter the pores and gaps of the expanded graphite. Under the action of ultrasound, cavitation bubbles form and rupture in the solvent medium, accompanied by the release of energy. The instantaneous implosion caused by cavitation phenomenon has a strong shock wave. The rapid formation and sudden collapse of cavitation bubbles in the liquid create a brief high-energy microenvironment, which can reach a high temperature of 5000K and a high pressure of about 500atrn in nanoseconds. The heating and cooling speed is greater than 109K/s. The high-speed jet generated separates the nano graphite flakes from the expanded graphite and enters the solvent medium. Therefore, the crushing of expanded graphite by ultrasound is a mechanism of shock wave action, which includes both the action of cavitation shock wave and micro jet. Scientists obtained micrometer graphite using ultrasonic grinding method. The method involves preparing expanded graphite through specific processes such as intercalation, water washing, drying, thermal shock, etc., dispersing lg in 400ml of ethanol water solution (70%), treating with 100W ultrasonic for 8-12 hours, and then filtering and drying the product after ultrasonic grinding. SEM testing shows that the diameter of the graphite sheet obtained after ultrasonic treatment is 13 bucket meters, with a thickness distribution of 10-100nm, and an average thickness of 52nm.