Gelatin-derived carbon: Carbonization mechanism and application in K-ion storage

Gelatin, a natural macromolecular substance formed by the hydrolysis of collagen, offers the advantages of abundant resources and low cost. It is a good precursor for the synthesis of N, O-doped carbon materials. Although some gelatin-derived carbon materials have been used for electrochemical energy storage, there have been few studies for the mechanism of gelatin carbonization. In addition, the influence of heteroatoms and defects on the K-ion storage performance remains unclear. In this work, in situ and ex situ characterization methods have been used to study the mechanism of gelatin carbonization. The pathways leading to formation of the carbon framework, heteroatom doping and defect generation in gelatin-based carbons during the pyrolysis process have been clearly identified. Moreover, by means of DFT calculations and experimental measurements, it has been confirmed that heteroatoms and defects both play important roles in improving the storage performance of potassium ions. By virtue of its abundance of both heteroatoms and defects, our optimized anode shows better electrochemical performance than graphite anodes. This study not only clarifies our understanding of carbonization mechanism and mechanism of K-ion storage in carbon materials, but also provides pathways for the synthesis and applications of new carbon-based anode materials for alkali-ion batteries.