Search

Output voltage and self‐discharge rate are two important performance indices for supercapacitors, which have long been overlooked, though these play a very significant role in their practical application. Here, a zinc anode is used to construct a zinc ion hybrid capacitor. Expanded operating voltage of the hybrid capacitor is obtained with novel electrolytes. In addition, significantly improved anti‐self‐discharge ability is achieved. The phosphorene‐based zinc ion capacitor exploiting a "water in salt" electrolyte with a working potential can reach 2.2 V, delivering 214.3 F g−1 after 5000 cycles. The operating voltage is further extended to 2.5 V through the use of an organic solvent as the electrolyte; the solvent is prepared by adding 0.2 m ZnCl2 into the tetraethylammonium tetrafluoroborate in propylene carbonate (Et4NBF4/PC) solvent, and it exhibits 105.9 F g−1 even after 9500 cycles. More importantly, the phosphorene‐based capacitors possess excellent anti‐self‐discharge performance. The capacitors retain 76.16% of capacitance after resting for 300 h. The practical application of the zinc ion capacitor is demonstrated through a flexible paper‐based printed microcapacitor. It is believed that the developed zinc ion capacitor can effectively resolve the severe self‐discharge problem of supercapacitors. Moreover, high‐voltage zinc ion capacitors provide more opportunities for the application of supercapacitors. [ABSTRACT FROM AUTHOR]

Aqueous batteries that use metal anodes exhibit maximum anodic capacity, whereas the energy density is still unsatisfactory partially due to the high redox potential of the metal anode. Current metal anodes are plagued by the dilemma that the redox potential of Zn is not low enough, whereas Al, Mg, and others with excessively low redox potential cannot work properly in aqueous electrolytes. Mn metal with a suitably low redox potential is a promising candidate, which was rarely explored before. Here, we report a rechargeable aqueous Mn‐metal battery enabled by a well‐designed electrolyte and robust inorganic–organic interfaces. The inorganic Sn‐based interface with a bottom‐up microstructure was constructed to preliminarily suppress water decomposition. With this bubble‐free interface, the organic interface can be formed via an esterification reaction of sucrose triggered by acyl chloride in the electrolyte, generating a dense physical shield that isolates water while permitting Mn2+ diffusion. Hence, a Mn symmetric cell achieves a superior plating/stripping stability for 200 hours, and a Mn||V2O5 battery maintains approximately 100 % capacity after 200 cycles. Moreover, the Mn||V2O5 battery realizes a much higher output voltage than that of the Zn||V2O5 battery, evidencing the possibility of increasing the energy density through using a Mn anode. This work develops a systematic strategy to stabilize a Mn‐metal anode for Mn‐metal batteries, opening a new door towards enhanced voltage of aqueous batteries. [ABSTRACT FROM AUTHOR]

Aqueous batteries that use metal anodes exhibit maximum anodic capacity, whereas the energy density is still unsatisfactory partially due to the high redox potential of the metal anode. Current metal anodes are plagued by the dilemma that the redox potential of Zn is not low enough, whereas Al, Mg, and others with excessively low redox potential cannot work properly in aqueous electrolytes. Mn metal with a suitably low redox potential is a promising candidate, which was rarely explored before. Here, we report a rechargeable aqueous Mn‐metal battery enabled by a well‐designed electrolyte and robust inorganic–organic interfaces. The inorganic Sn‐based interface with a bottom‐up microstructure was constructed to preliminarily suppress water decomposition. With this bubble‐free interface, the organic interface can be formed via an esterification reaction of sucrose triggered by acyl chloride in the electrolyte, generating a dense physical shield that isolates water while permitting Mn2+ diffusion. Hence, a Mn symmetric cell achieves a superior plating/stripping stability for 200 hours, and a Mn||V2O5 battery maintains approximately 100 % capacity after 200 cycles. Moreover, the Mn||V2O5 battery realizes a much higher output voltage than that of the Zn||V2O5 battery, evidencing the possibility of increasing the energy density through using a Mn anode. This work develops a systematic strategy to stabilize a Mn‐metal anode for Mn‐metal batteries, opening a new door towards enhanced voltage of aqueous batteries. [ABSTRACT FROM AUTHOR]

Redox‐active organic materials, as a new generation of sustainable resources, are receiving increasing attention in zinc‐ion batteries (ZIBs) due to their resource abundance and tunable structure. However, organic molecules with high potential are rare, and the voltage of most reported organic cathode‐based ZIBs is less than 1.2 V. Herein, we explored the redox process of p‐type organics and figured out the relationship between energy change and voltage output during the process. Then, we proposed a dual‐step strategy to effectively tune the energy change and eventually improve the output voltage of the organic electrode. Combining the regulation of the electron cloud of organic molecules and the manipulation of the solvation structure, the output voltage of an organosulfur compound based ZIB was greatly increased from 0.8 V to 1.7 V. Our results put forward a specific pathway to improve the working voltage and lay the foundation for the practical application of organic electrodes. [ABSTRACT FROM AUTHOR]

Redox‐active organic materials, as a new generation of sustainable resources, are receiving increasing attention in zinc‐ion batteries (ZIBs) due to their resource abundance and tunable structure. However, organic molecules with high potential are rare, and the voltage of most reported organic cathode‐based ZIBs is less than 1.2 V. Herein, we explored the redox process of p‐type organics and figured out the relationship between energy change and voltage output during the process. Then, we proposed a dual‐step strategy to effectively tune the energy change and eventually improve the output voltage of the organic electrode. Combining the regulation of the electron cloud of organic molecules and the manipulation of the solvation structure, the output voltage of an organosulfur compound based ZIB was greatly increased from 0.8 V to 1.7 V. Our results put forward a specific pathway to improve the working voltage and lay the foundation for the practical application of organic electrodes. [ABSTRACT FROM AUTHOR]