Biomass derived hierarchically porous carbon inherent structure as an effective metal free cathode for Li-O₂/air battery

A hierarchical porous carbon framework derived from betel-nut is synthesized and employed as a bifunctional cathode in a Li-O₂/air battery. The prepared betel nut derived activated porous carbon (BNAPC) material exhibits an ordered and merged tube-like porous morphology and a high specific surface area of 768 m²/g. The presence of both meso and micro porous leads to a well-developed 3D interconnected carbon framework, which provides an efficient path for the diffusion of the reactant (oxygen as well as air) and also allows stocking the discharge product of Li₂O₂. Therefore, it exhibits a high specific capacity and excellent rate performance. A maximum discharge capacity of 9560 and 2000 mAh/g at a current density of 100 mA/g for oxygen and ambient air respectively as the reactant is achieved. The prepared material also exhibits reversible cyclic stability of 27 cycles with a specific capacity of 1000 mAh/g at a 100 mA/g current density in oxygen atmosphere.