Flexible Zn-ion batteries based on manganese oxides: Progress and prospect

The ever-growing market of wearable electronic devices has greatly stimulated the rapid development of flexible Zn-ion batteries(ZIBs).Manganese oxides are one of the most commonly used hosts for zinc ion accommodation and thus receive particular research interest for high-performance flexible ZIB constructions.In this review,a comprehensive summary of the recent development of flexible ZIBs with manganese oxides as cathode materials is presented.Apart from the brief introduction of flexible electronic devices and ZIBs,the charge storage mechanisms and crystal structures of various manganese oxides are summarized.Modifications of the cathode materials in terms of morphology,conductivity,structures,and flexibilities are illustrated in detail,together with the demonstration of structure-performance relationships and applications in flexible ZIBs.Finally,limitations to be overcome are indicated and the future work directions are proposed.

Surface engineering towards high-energy carbon cathode for advanced aqueous zinc-ion hybrid capacitors

Opportunities coexist with challenges for the development of carbon-based cathodes with a high energy density applied for zinc ion hybrid capacitors(ZIHCs).In the present study,a facile and effective surface engineering approach is demonstrated to greatly improve the energy storage ability of commercial carbon paper(CP)in ZIHC.Benefiting from the introduced oxygen functional groups,larger surface area and improved surface wettability upon air calcination,the assembled aqueous ZIHC with the functionalized carbon paper(FCP)exhibits a much higher areal capacity of 0.22 mAh/cm^(2)at 1 mA/cm^(2),outperforming the counterpart with blank CP by over 5000 times.More importantly,a superior energy density and power density of 130.8μWh/cm^(2)and 7460.5μW/cm^(2),are respectively delivered.Furthermore,more than 90%of the initial capacity is retained over 10000 cycles.This surface engineering strategy to improve the energy storage capability is potentially applicable to developing a wide range of high-energy carbon electrode materials.

Facile access to β-hydroxyl ketones via a cobalt-catalyzed ring-opening/hydroxylation cascade of cyclopropanols

A cobalt-catalyzed ring-opening/hydroxylation cascade of highly strained cyclopropanols has been developed for the first time. The reaction was conducted under open-air atmosphere to afford a broad series of structurally diverse β-hydroxy ketones in moderate to good yields with high regioselectivity.The protocol features mild reaction conditions, simple operation, high-functional-group tolerance, facile scalability, and heterocycle compatibility.

Structural regulation strategies towards high performance organic materials for next generation aqueous Zn-based batteries

Environmental degradation has promoted the exploitation of novel energy-storage devices.Electrochemical en-ergy technologies,including supercapacitors and aqueous batteries,are highly desirable for energy storage appli-cations.Among them,aqueous zinc-based batteries(AZBs)are highly valued because of their inherent safety and low cost.One class of emerging materials favorably employed in these devices are organic cathodes,featuring resource renewability,cost-effectiveness,and adjustable electrochemical properties via facile structural modi-fication compared to the conventional inorganic cathodes.To date,various types of organic compounds have been developed and applied to AZBs.This paper comprehensively reviews the mechanisms involved in organic electrode material reactions,highlighting the structural modifications,including morphological,molecular,func-tional group,crystal,and electronic structures,affecting the final device performance.Conclusively,the prospects of practical applications of zinc/organic aqueous battery are delineated.