Effects of molecular structure and functional groups on the performance of carbonyl organic compounds as cathodes for aluminum batteries

Organic electrode materials have received extensive and long-term research and attention due to their safety, environmental friendliness, and lower price, and have also been used in aluminum-ion batteries (AIBs). The performance of existing applications in AIBs using organics as cathode materials still lags behind inorganics, especially in terms of battery capacity and voltage. Carbonyl groups have great potential as active sites for redox reactions in AIBs. Here, six carbonyl organic compounds were used as cathode for AIBs to investigate their performance differences and the factors affecting the performance. Through a combination of experiments and theoretical calculations (DFT), BDTO was first identified as the best performing cathode material in six organics, leading the organic materials with a high specific capacity of 236.8 mAh g−1 and 500 stable cycles. Moreover, it is proved that the symmetry of ring structure and molecular structure has an important influence on the properties of organic cathodes. These research results provide a direct reference for the selection and design of rational organic as cathode materials, which is an important step on the road to develop high-performance aluminum-organic batteries as soon as possible.