Biomass-derived metal-free heteroatom doped nanostructured carbon electrocatalysts for high-performance rechargeable lithium–air batteries

Abstract

Renewable energy sources are crucial for addressing the energy crisis and global warming, but their intermittent nature necessitates storage. Metal–air batteries, such as Li–air batteries, offer high specific capacity and environmental friendliness but face issues like poor reaction kinetics and high overpotential during charging and discharging. To address these issues, noble metal-based catalysts have been utilized, which require the replacement of such precious and scarce resources with affordable and commercially accessible materials. Biomass, a renewable resource, plays a critical role in preparing carbon-based electrocatalysts and porous cathodes with excellent performance due to its rich heteroatom and pore structure, and potential doping and co-doping with transition metals and their oxides. Metal-free biomass carbon nanostructured bifunctional electrocatalysts have been identified as potential alternatives for the next generation of oxygen reduction and evolution reactions. These catalysts have comparable catalytic activity and improved stability compared to the current state-of-the-art Pt-based catalysts, making them essential for the commercialization of lithium–air batteries. Thus, this paper reviews the most recent advances in biomass-derived metal-free heteroatom-doped nanostructured carbon electrocatalysts for rechargeable lithium–air batteries and discusses how different biomass sources affect the cathode's composition, morphology, and structure–activity relationship. It gives a reasonable approach to doping methodologies, which may guide non-noble electrocatalyst and electrode designs.