Multi-Scale Structure Engineering of ZnSnO3 for Ultra-Long-Life Aqueous Zinc-Metal Batteries

Suppressing the severe water-induced side reactions and uncontrolled dendrite growth of zinc (Zn) metal anodes is crucial for aqueous Zn-metal batteries to achieve ultra-long cyclic lifespans and promote their practical applications. Herein, a concept of multi-scale (electronic-crystal-geometric) structure design is proposed to precisely construct the hollow amorphous ZnSnO₃ cubes (HZTO) for optimizing Zn metal anodes. In situ gas chromatography demonstrates that Zn anodes modified by HZTO (HZTO@Zn) can effectively inhibit the undesired hydrogen evolution. The pH stabilization and corrosion suppression mechanisms are revealed via operando pH detection and in situ Raman analysis. Moreover, comprehensive experimental and theoretical results prove that the amorphous structure and hollow architecture endow the protective HZTO layer with strong Zn affinity and rapid Zn²⁺ diffusion, which are beneficial for achieving the ideal dendrite-free Zn anode. Accordingly, excellent electrochemical performances for the HZTO@Zn symmetric battery (6900 h at 2 mA cm^-2 , 100 times longer than that of bare Zn), HZTO@Zn||V₂ O₅ full battery (99.3% capacity retention after 1100 cycles), and HZTO@Zn||V₂ O₅ pouch cell (120.6 Wh kg^-1 at 1 A g^-1 ) are achieved. This work with multi-scale structure design provides significant guidance to rationally develop advanced protective layers for other ultra-long-life metal batteries.

Macromolecular Engineering of Poly(catechol) Cathodes towards High-Performance Aqueous Zinc-Polymer Batteries

Aqueous zinc-polymer batteries (AZPBs) comprising abundant Zn metal anode and redox-active polymer (RAP) cathodes can be a promising solution for accomplishing viable, safe and sustainable energy storage systems. Though a limited number of RAPs have been successfully applied as organic cathodes in AZPBs, their macromolecular engineering towards improving electrochemical performance is rarely considered. In this study, we systematically compare performance of AZPB comprising Zn metal anode and either poly(catechol) homopolymer (named P(4VC)) or poly(catechol) copolymer (named P(4VC86-stat-SS14)) as polymer cathodes. Sulfonate anionic pendants in copolymer not only rendered lower activation energy and higher rate constant, but also conferred lower charge-transfer resistance, as well as facilitated Zn2+ mobility and less diffusion-controlled current responses compared to its homopolymer analogue. Consequently, the Zn||P(4VC86-stat-SS14) full-cell exhibits enhanced gravimetric (180 versus 120 mAh g-1 at 30 mg cm-2) and areal capacity (5.4 versus 3.6 mAh cm-2 at 30 mg cm-2) values, as well as superior rate capability both at room temperature (149 versus 105 mAh g-1 at 150 C) and at -35 °C (101 versus 35 mAh g-1 at 30 C) compared to Zn||P(4VC)100. This overall improved performance for Zn||P(4VC86-stat-SS14) is highly encouraging from the perspective applying macromolecular engineering strategies and paves the way for the design of advanced high-performance metal-organic batteries.

An In Situ Cross-Linked Nonaqueous Polymer Electrolyte for Zinc-Metal Polymer Batteries and Hybrid Supercapacitors

This work reports the facile synthesis of nonaqueous zinc-ion conducting polymer electrolyte (ZIP) membranes using an ultraviolet (UV)-light-induced photopolymerization technique, with room temperature (RT) ionic conductivity values in the order of 10^-3 S cm^-1 . The ZIP membranes demonstrate excellent physicochemical and electrochemical properties, including an electrochemical stability window of >2.4 V versus Zn|Zn²⁺ and dendrite-free plating/stripping processes in symmetric Zn||Zn cells. Besides, a UV-polymerization-assisted in situ process is developed to produce ZIP (abbreviated i-ZIP), which is adopted for the first time to fabricate a nonaqueous zinc-metal polymer battery (ZMPB; VOPO₄ |i-ZIP|Zn) and zinc-metal hybrid polymer supercapacitor (ZMPS; activated carbon|i-ZIP|Zn) cells. The VOPO₄ cathode employed in ZMPB possesses a layered morphology, exhibiting a high average operating voltage of ≈1.2 V. As compared to the conventional polymer cell assembling approach using the ex situ process, the in situ process is simple and it enhances the overall electrochemical performance, which enables the widespread intrusion of ZMPBs and ZMPSs into the application domain. Indeed, considering the promising aspects of the proposed ZIP and its easy processability, this work opens up a new direction for the emergence of the zinc-based energy storage technologies.