ALKANE-BASED COMPOSITION WITH GRAPHENE CONTENT FOR STORING THERMAL ENERGY AND PROCESS FOR PREPARING THE SAME

摘要

The invention relates to alkane-based composite materials with graphene content exhibiting high thermal properties, thermal conductivity and transfer rate and to a process for preparing the same, they being meant to be used as phase-change materials in electronics, high power batteries, Li-ion batteries, in motor-vehicle industry, constructions, agriculture or the like. According t the invention, the composite materials contain multi-layer graphenes directly intercalated in the lamellar structure of paraffin, by homogenizing them directly in the paraffin matrix, they exhibit thermal conductivity in the range of 0.290...0.320 W/mK and a thermal transfer rate enhanced by up to 40% as compared with the paraffin, without diminishing the thermal storage capacity. The process, as claimed by the invention, consists in exfoliating natural carbon flakes using an ultra-mixer, an amount of 90...110 g of paraffin previously heated to a temperature of 80...110°C being admixed to 1 g of natural graphite, after which the mixture is subjected to an ultra-mixing process, in a first stage at 400...600 rpm, for 5...10 min, after which the speed is increased to 4800...5200 rpm, for 30...40 min, to result in alkane-based composite materials with multi-layer graphene content.