P-Doped Hive-like Carbon Derived from Pinecone Biomass as Efficient Catalyst for Li–O₂ Battery

Abstract

Development of energy storage materials with high energy density to fulfill the demand of next generation batteries is a blistering topic under immense debate. The Li–O2 battery is attracting much more attention for its enhanced theoretical energy density compared to the traditional Li-ion battery. Porous oxygen-breathing catalysts, especially biomass-derived materials, could offer plenty of oxygen diffusion paths and Li2O2 formation space, which is beneficial for the Li–O2 battery. In this work, a simple method is used to prepare phosphorus doped pinecone-derived hive-like carbon (P-PHC) with a porous structure. This P-PHC as a non-noble catalyst owns unique architecture as well as active P sites, a large BET surface area, and abundant defects on the surface. Ex-situ SEM images demonstrate that the porous structure of P-PHC remains during the discharging process. EIS results reveal that P-PHC could guarantee better charge transfer as well as better O2 and Li+ diffusion. Due to the synergistic effect of higher activity from abundant defects on the surface as well as better O2 and Li+ diffusion from the unique hive-like structure, P-PHC delivers a large discharge specific capacity of 24 500 mAh g–1 at a current density of 100 mA g–1 and a durable cycling number of 205 times when operated at a specific capacity of 1 Ah g–1 under a current density of 0.5 A g–1. This work proposes a sustainable strategy of reusing wasted biomass for rechargeable batteries, which would be beneficial to the energy and environment fields.