An electrolyte-rich nano-organic cathode constructs an ultra-high voltage Zinc-ion battery.

[Display omitted] • A strategy for storing electrolytes at the cathode is first proposed. • The prepared PAZ electrode possesses extremely high conductivity. • The assembled battery has an ultrahigh operating voltage window of 2.4 V. • The energy storage mechanism of Zn2+ and polyanion doping and dedoping is proposed. • The strategy enables the operation of batteries with low electrolyte content. To realize green and sustainable energy storage systems, it is urgent to propose emerging strategies to construct and understand the relationship between electrode materials and electrolytes. Based on the strategy of storing the electrolyte in an organic cathode, we prepare a Zn2+-doped polyaniline (PAZ) nano-organic cathode with a re-doping method, which possesses high crystallinity in the (0 1 0) plane and high conductivity compared with conventional H+-doped polyaniline (PA). The resultant Zn//PAZ battery exhibits outstanding electrochemical performance for 3000 cycles at an ultra-high voltage of 2.4 V, attributed to the enhancement of electrolyte concentration and reduction of free water stemming from the dedoping of PAZ. A hybrid charge storage mechanism including Zn2+ and multi-anions insertion/extraction is also demonstrated for the Zn//PAZ batteries during the charge/discharge process. To further expand the practical applications of the strategy, we manufacture an electrolyte-free Zn//PAZ battery, which achieves acceptable performance for 400 cycles. This research provides insight into the relationship between the electrolyte and re-doped polyaniline organic cathode and opens a new avenue for emerging Zinc batteries. [ABSTRACT FROM AUTHOR]