Biochar electrocatalysts for clean energy applications

With the enormous demand for energy, the usages of fossil fuels have been extensive leading to environmental problems, for example, global warming effects on the environment and its cascading effect on and threat to human existence. Recently, the intensive studies on the alternative energy technologies are under R&D developments. Among various technologies, clean energy devices such as supercapacitors (SCs), lithium-ion batteries (LIBs), and fuel cells (FCs) have been reported to be the promising in and efficient options for easing human life. In the applications of aforementioned devices, carbon is one of the most indispensable platform materials. Therefore, the developments on the technology frontier showing the way to cost-effective methods to fabricate high-efficient and environment-friendly carbon from renewable resources are desirable. Biochars with plentiful surface functional groups and facilely tuned porosity could be a prospective candidate for the sustainable electrodes in the clean energy devices. In this chapter, three electrochemical energy storage/conversion devices using biochars as electrodes are reported, including SCs, LIBs and FCs. These biochars which combine with metal oxides (e.g., transition-metal oxides) and nonmetal elements (e.g., N-doping) with unique properties are proposed. The results demonstrate substantial possibility of biochar-based materials for clean energy applications. Some prospects in and recommendations on clean energy applications that are worthy of further research in the future are also made.