hide
Free keywords:
anodes, hybrid materials, nitrogen-doped carbon, porous carbon, Sodium ion capacitor
Abstract:
The nanoscale combination of a conductive carbon and a carbon-based material with abundant heteroatoms is a promising method to overcome the common limitation that the latter have high affinity to alkali metal ions but low electronic conductivity. The synthetic protocol for their combination as well as the individual ratios and structures are all important aspects influencing the properties of such multifunctional compounds. Their interplay is herein investigated by infiltration of a porous ZnO-templated carbon (ZTC) with nitrogen-rich carbon obtained by condensation of hexaazatripenylene-hexacarbonitile (HAT-CN) at 550-1000°C. The density of lithiophilic sites can be controlled by HAT-CN content and condensation temperature. Lithium storage properties are significantly improved in comparison to those of the individual compounds and their physical mixtures. Depending on the uniformity of the formed composite, loading ratio and condensation temperature have different influence. Most stable operation at high capacity per used monomer is achieved with a slowly dried composite with a HAT-CN:ZTC mass ratio of 4:1, condensed at 550°C, providing more than 400 mAh g−1 discharge capacity at 0.1 A g−1 and a capacity retention of 72% after 100 cycles of operation at 0.5 A g−1 due to the homogeneity of the composite and high content of lithophilic sites. This article is protected by copyright. All rights reserved.
