A rechargeable zinc ion capacitor (ZIC) employing a metallic anode, nature-abundant materials-derived high-performance cathode, and an aqueous electrolyte represents an interesting combination of high capacitance, high power, safety operation, and overall a sustainable and economic system, which make them a leading power source to portable consumer electronics. However, it is often a challenge to fabricate a large-area flexible device with a metallic anode due to the characteristic rigidity of the metal. Herein we present a high-performance aqueous ZIC based on abundant agricultural waste biomass (Areca Catechu sheath)-derived highsurface-area (2760 m 2 /g) mesoporous multilayer-stacked carbon sheets as the capacitive electrode in 1 M ZnSO 4 electrolyte. In coin cell configuration, the ZIC showed a high specific capacitance of 208 F/g at 0.1 A/g, a good rate capability, and an outstanding cyclic stability with 84.5% capacitance retention after 10 000 cycles at a current density of 5 A/g. We also demonstrate an easy and scalable strategy to fabricate a large-area flexible zinc ion capacitor with laser-scribed carbon (LSC@PI), scribed on a polyimide film with customizable area as the flexible current collector for both anode and cathode. Electrodeposition of zinc onto LSC@PI as anode showed a very low plating stripping overpotential, and the flexible sandwich-type ZIC with an electrolyte-soaked paper separator exhibited excellent flexibility and a high areal capacitance of 128.7 mF/cm 2 at 100 mA/cm 2 current when bended at an angle of 110°, corresponding to an energy density of 32.6 μW h/cm 2 . When the current was increased by 20 times, the flexible device under bending condition could provide an energy density of 11 μW h/cm 2 at a high power density of 1.906 W/cm 2 . The synthesized materials were characterized by X-ray diffraction (XRD), RAMAN, Field Emission Scanning Electron Microscope (FESEM), and Brunauer−Emmett−Teller (BET) analysis, whereas the electrochemical performances were measured in terms of cyclic voltammetry (CV), galvanostatic charge−discharge (GCD), and Electrochemical impedance spectroscopy (EIS) analysis.

Developing high-performance, safer, and affordable flexible batteries is of urgent need to power the fast-growing flexible electronics market. In this respect, zinc-ion chemistry employing aqueous-based electrolytes represents a promising combination considering the safety, cost efficiency, and both high energy and high-power output. Herein, we represent a highperformance flexible in-plane aqueous zinc-ion miniaturized battery constructed with all electrodeposited electrodes, i.e., MnO 2 cathode and zinc anode with polyimide-derived interdigital patterned laser-scribed carbon (LSC) as the current collector as well as the template for electrodeposition. The LSC possesses a cross-linked network of graphitic carbon sheet, which offers large surface area over low footprint and ensures active materials loading with a robust conductive network. The LSC with high zincophilic characteristic also offers dendrite-free zinc deposition with very low Zn 2+ plating stripping overpotential. Benefitting from the Zn//MnO 2 -rich redox chemistry, the ability of the 3D LSC network to uniformly distribute reaction sites, and the architectural merits of in-plane interdigitated electrode configuration, we report very high capacity values of ∼549 mAh/g (or ∼523 μAh/cm 2 ) and 148 mAh/g (or 140 μAh/cm 2 ) at 0.1 A/g (0.095 mA/cm 2 ) and 2 A/g (1.9 mA/cm 2 ) currents, respectively. The device was also able to maintain a high capacity of 196 mAh/g (areal capacity of 76.19 μAh/cm 2 ) at 1 A/g (0.95 mA/cm 2 ) current after 1350 cycles. The flexibility of the device was demonstrated in polyacryl amide (PAM) gel polymer soaked with a 2 M ZnSO 4 and 0.2 M MnSO 4 electrolyte, which exhibited a comparable specific capacity of ∼102−110 mAh/g in flat condition and different bending (100°or 160°bending) conditions. The device does not use any conventional current collector, separator, and conductive or polymer additives. The overall process is highly scalable and can be completed in less than a couple of hours.

Herein we demonstrate the fabrication of a highperformance rechargeable zinc ion battery based on a laser-scribed carbon (LSC)-supported electrodeposited zinc anode and vanadium oxide (V 5 O 12 •6H 2 O) cathode with a planar-interdigitated electrode architecture and a polymeric solid electrolyte. This is the first report on a full-cell Zn//V 5 O 12 •6H 2 O planar flexible battery where a practical zinc loading (∼76 times that of the cathode loading) is maintained. The electrodeposited Zn@LSC anode showed excellent stability with very low polarization over the tested 500 h (750 cycles). We demonstrate a high initial capacity of 325 mAh/g for the Zn//V 5 O 12 •6H 2 O planar battery at 2 A/g in a 3 M ZnSO 4 aqueous electrolyte. However, the capacity dropped to 70 mAh/g only after 1000 cycles. Nonetheless, the cell performance, in particular the cycle stability, was significantly improved when the aqueous electrolyte was replaced with a gelatin/ZnSO 4 / glutaraldehyde-based solid-state electrolyte. The solid-state planar battery showed a high initial capacity of 556 mAh/g at 0.1 A/g current corresponding to an energy density of 381 Wh/kg active cathode and an impressive cycle stability with only 0.0067% capacity loss per cycle over 5500 cycles at 2 A/g. The cell also demonstrated excellent flexibility with comparable specific capacity under different bending conditions. The solid-state device exhibited a high areal energy density of 72 and 14 μWh/cm 2 at the corresponding areal power density of 130 and 2511 μW/cm 2 , respectively. Overall, the rapid (complete device fabrication in ∼2 h) and scalable fabrication approach, high performance with excellent safety features, and accompanying high flexibility make the as-fabricated Zn// V 5 O 12 •6H 2 O planar flexible battery suitable for next-generation flexible electronics applications.

generated from various processes such as photocatalytic/electrolytic and thermal processes from different hydrogen-based sources such as water, biomass, boron hydrides, hydrogen sulfides, natural gas, and coal. [1] Among different strategies, water electrolysis is the simplest and most environmental friendly approach for the production of hydrogen of the highest purity. [2] Hydrogen evolution reaction (HER) is one of the half-cell reactions in overall water splitting which occurs at the cathode, whereas, oxygen evolution reaction (OER) is observed at the anode side. The OER is favorable in alkaline media, whereas the HER is favorable in acidic media. Irrespective of the medium, nanoscale engineering of catalyst to improve ohmic contact, mechanical robustness, and hydrophilicity to accelerate the H 2 or O 2 gas bubble separation and improve electrolyte contact are extremely important to facilitate the overall water splitting. [3] Several transition metals, in particular Ni, Co, and Fe based engineered materials in the form of oxides, hydroxides, layer double hydroxides, and metal organic framework, have been successfully demonstrated as efficient OER electrocatalyst in alkaline media. [4] HER involve the reduction of proton in acidic