Graphitic carbon from catalytic methane decomposition as efficient conductive additives for zinc-carbon batteries

Catalytic decomposition of methane (CDM) into hydrogen and solid carbon materials (CH4 -> 2H(2) + C) is a promising approach to achieve environmentally friendly H-2 production. However, large amounts of carbon (i.e., H-2 to carbon mass ratio of 1 to 3) is generated as a solid by-product. Herein, we show that graphitic carbon materials generated in CDM on iron ore catalysts can be purified by either standard high-temperature thermal treatment (Carbon-T) or an alternative electrochemical method (Carbon-E) to reach the purity of 99.82 and 99.59 wt%, respectively. The purified carbon materials show a high electrical conductivity up to 98 S cm(-1) when incorporated in MnO2 cathodes and a good electrolyte (1 M ZnSO4) absorption capability up to 4.20 mg mg(-1), which are two essential properties for carbon conductive additives. Zinc-carbon batteries assembled using these carbon materials show advantages in electrode conductivity, specific capacity, rate performance, internal resistance, and long-term stability compared with commercial carbon conductive additives. The high purity graphitic carbon materials from CDM can serve as efficient carbon conductive additives for batteries, opening a new path to producing a value-added commodity as a by-product of eco-friendly H-2 production. (C) 2022 Elsevier Ltd. All rights reserved.

Automated summary

The research demonstrates that graphitic carbon materials generated in the catalytic decomposition of methane can be purified to high purity using either high-temperature thermal treatment or an alternative electrochemical method. These purified carbon materials show excellent conductivity and absorption capability, and can be used as efficient carbon conductive additives for batteries.