Fabrications and Na⁺ Storage Characteristics of Nitrogen-doped Biomass-derived Carbon Materials

Abstract

The biomass-derived carbon materials were successfully fabricated by precursor mixtures of eggplants, urea and CaCl₂. It is promisingly observed that controlling the mixing ratios of eggplants, urea and CaCl₂ can regulate the structures of fabricated carbon materials. On the basis of investigations about correlations between structures and Na⁺ storage capacity, it is verified that weight ratio of eggplants : urea : CaCl₂ = 1 : 2 : 2 is optimal to fabricate the carbon materials, which have the suitable porous structures and specific surface area to store Na⁺. For instance, the fabricated carbon materials show the Na⁺ storage capacity is 200.8 mAh/g at 0.1 A/g, after being carried out the charge-discharge 500 times. Meanwhile, the same materials also display the impressive long cycling performance. When cycling the charge-discharge 1000 times at 2.0 A/g, the fabricated carbon materials still manifest the Na⁺ storage capacity at 137.8 mAh/g.