Low-cost carbonyl polymer design for high-performance lithium-organic battery cathodes

Carbonyl polymers, such as poly(anthraquinonyl sulfide) (PAQS) and poly(benzoquinonyl sulfide) (PBQS), are typically selected as cathode materials for lithium-organic batteries (LOBs) because of their inherent high theoretical capacity and low solubility in the electrolyte. However, their commercialization is hindered by their relatively complex synthesis routes, low yields, and high cost. Herein, a carbonyl polymer poly(piperazine-alt-benzoquinone) (NP2), obtained from the polymerization of vanillin and piperazine with oxidative amination at the theoretical production cost of US $0.48 per gram, exhibits a high reversible capacity of 257 mAh g−1, leading to a cost performance of US $0.19 per 100 mAh, which is superior to the reported carbonyl polymers. Furthermore, ex situ X-ray photoelectron spectroscopy and ex situ and in situ Fourier-transform infrared measurements release the reversible electrochemical reaction mechanism of NP2 based on carbonyl redox chemistry. This study demonstrates a simple and effective strategy to synthesize low-cost carbonyl polymers, which will pave the way for their future application in high-performance LOBs.