Hierarchical porous CS@Ce-MnO₂ as cathode for energy-dense and long-cycling flexible aqueous zinc-ion batteries

Aqueous zinc-ion batteries (ZIBs) have been considered one of the most promising flexible chemical power sources, because of their affordable cost, absolute security, and lightweight. However, the development of flexible aqueous ZIBs has been hindered by cathode materials due to their unsatisfied capacity, unstable structure, and ambiguous electrochemical energy storage mechanism. To address the above issues, a high-performance manganese cerium-doped dioxide-based core–shell hybrid structure cathode (CS@Ce-MnO₂) has been successfully prepared via a facile low-temperature liquid-phase reaction strategy. Benefit from the delicately designed hierarchical carbon spheres core and cerium-doped manganese dioxide nanosheets shell structure, the capacity and stability of CS@Ce-MnO₂ based flexible ZIBs has been dramatically improved, and the origin of the improved electrochemical performance and storage mechanism was demonstrated by electrochemical methods and ex-site x-ray diffraction (XRD) and scanning electron microscopy (SEM). The principal reason for the high reversible specific capacity is the plausible Zn²⁺ and H⁺co-insertion/extraction, while the porous structure of the carbon spheres contributes to the improved electron conduction and ion transport in the MnO₂ matrix. This work provides a new opportunity for high-performance flexible aqueous zinc-ion batteries.