Air-expansion induced hierarchically porous carbonaceous aerogels from biomass materials with superior lithium storage properties

Abstract

Traditional methods for the preparation of carbon aerogels, such as a sol–gel method, hydrothermal method, freeze-drying method and the direct carbonization of biomass materials, have been more and more limited in their applications due to their high cost, complex processes and the accompanying volume shrinkage in the preparation process. In this paper, we developed a novel air-expansion method for the preparation of porous carbonaceous aerogels with hierarchically macroporous, mesoporous and microporous structures from rice. The main advantages of an air-expansion method are large-scale preparation, low cost, a simple technique and most importantly it keeps the initial shape/structure and avoids shrinkage of the carbon aerogels owing to the air-expansion process of rice generating many macroporous structures for supporting the aerogel framework. When used as an anode for lithium ion batteries, rice-based carbonaceous aerogels exhibit a superior specific capacity and possess a good rate capability. This study gives a better insight into the preparation of carbonaceous aerogels from other grains as well as their potential applications in lithium ion batteries.