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[Display omitted] Researchers have recently redirected their attention toward aqueous batteries in pursuit of safety and affordability. The water-based electrolyte promises many appealing merits such as non-flammability and environmental friendliness but is also cursed with low energy density. In an attempt of lifting the curse, many efforts have been made to re-formulate the aqueous electrolyte, which seems unlikely to succeed without understanding the interplay between electrolytes' physical properties and electrochemical performance. Starting from the composition of electrolytes, we discuss how various formulas of zinc ion battery electrolytes lead to diverse electrochemical performances. By evaluating the electrochemical performance of batteries in five metrics, it provides a la carte electrolyte designing strategies with different battery purposes. [ABSTRACT FROM AUTHOR]

Functionalizing carbon cathode surfaces with oxygen functional groups is an effective way to simultaneously tailor the fundamental properties and customize the electrochemical properties of aqueous Zn‐ion hybrid capacitors. In this work, the oxygen functional groups of chemically reduced graphene oxide (rGO) are systematically regulated via a series of reductants and varied experimental conductions. Carboxyl and carbonyl have been proven to significantly enhance the aqueous electrolyte wettability, Zn‐ion chemical adsorption, and pseudocapacitive redox activity by experimental study and computational analysis. The rGO cathode produced through hydrogen peroxide assisted hydrothermal reduction exhibits a specific capacitance of 277 F g−1 in 1 m ZnSO4 after optimization of surface oxygen functional groups. In addition, a quasi‐solid‐state flexible Zn‐ion hybrid capacitor (ZHC) with a polyacrylamide gel electrolyte and a high loading mass of 5.1 mg cm−2 are assembled. The as‐prepared quasi‐solid state ZHC can offer a superior areal capacitance of 1257 mF cm−2 and distinguished areal energy density of 342 µW h cm−2. The significant enhancement of redox activity and Zn‐ion storage capability by regulating the oxygen functional groups can shed light on the promotion of electrochemical charge storage properties even beyond protic electrolyte systems. [ABSTRACT FROM AUTHOR]

Despite the high potential impact of aqueous battery systems, fundamental characteristics such as cost, safety, and stability make them less feasible for large-scale energy storage systems. One of the main barriers encountered in the commercialization of aqueous batteries is the development of large-scale electrodes with high reversibility, high rate capability, and extended cycle stability at low operational and maintenance costs. To overcome some of these issues, the current research work is focused on a new class of material based on phenethylammonium bismuth iodide on fluorine doped SnO2-precoated glass substrate via aerosol-assisted chemical vapor deposition, a technology that is industrially competitive. The anode materials were electrochemically investigated in Zn2+ aqueous electrolytes as a proof of concept, which presented a specific capacity of 220 mAh g−1 at 0.4 A g−1 with excellent stability after 50 scans and capacity retention of almost 100%.

[Display omitted] • The ZEESD avoids heavy Zn metals and addresses the dendrite problem. • Working states can be monitored by chromatic transition of the ZEESD. • The ZEESD presents excellent environment suitability at −30 °C ∼ 60 °C. • The ZEESD possesses high energy storage capacity and excellent cycle stability. Zn-ion electrochromic energy storage devices (ZEESDs) incorporate electrochromism and energy storage into one platform that can visually indicate the working status through a real-time color change, attracting considerable attention in energy-saving buildings and intelligent electronics. However, typical ZEESDs generally consist of Zn metal electrodes and normal liquid electrolytes, resulting in the dendrite issues and restricted operating temperatures as well as inferior cycle stability. Herein, an all-solid-state dendrite-free ZEESD was constructed based on polyaniline (PANI) positive electrode, monoclinic WO 3 (m -WO 3) negative electrode and Zn2+-based gel electrolyte. Benefiting from the complementary synergistic effect of electrodes and electrolytes, the resultant ZEESD avoids heavy Zn metals, addresses the dendrite formation problem, and exhibits remarkable electrochromic and electrochemical performances. The prototype ZEESD possesses high energy/power density (97 Wh kg−1/976.2 W kg−1 and 28.6 μWh cm−2/0.27 mW cm−2), large optical modulation (∼52.4%@630 nm), high coloration efficiency (96.8 cm2 C−1 at 630 nm), along with outstanding cycling stability (∼94.4% capacity retention even after 6000 cycles). Impressively, the quasi-solid-state electrolyte maintained outstanding electrochemical activity enabling the ZEESD to cycle efficiently even under hash temperatures, presenting enormous potential for intelligent electronics in all-climate (−30 °C to 60 °C) conditions. This work provides a novel strategy to construct next-generation dendrite-free Zn-ion electrochromic energy storage devices for innovative consumer electronics even in harsh environments. [ABSTRACT FROM AUTHOR]

Inhibiting the growth of dendrites, one of the most serious issues faced by zinc-ion batteries (ZIBs) is addressed by coating the Zn anode with a layer of poly(carbazole)-carbon nanotubes (PCz@CNTs) composite. The electrically conducting robust composite overlayer ensures that the Zn-deposition during charging cycles is homogeneous and completely free of any fiber-like growth. This is confirmed from the cross-sectional electron microscopy analysis of post-cycled PCz@CNTs@Zn electrode. A vanadium oxide nanorods-porous graphitic flakes (V 6 O 13 NRs@PGFs) composite is used as a cathode. It has a large specific surface area, affording short ion-diffusion distances and many vacant sites thus permitting facile Zn2+ ion ingress and egress, is used. A remarkable performance results for the non-aqueous ZIB: V 6 O 13 NRs@PGFs//PCz@CNTs@Zn with a capacity of 286 mAh g−1 after 300 cycles at 30 mA g−1 (with 98% capacity retention), energy density of ∼172 Wh kg−1 and a nominal voltage of 1.8 V. It is significantly enhanced compared to its analogous ZIB of V 6 O 13 NRs@PGFs//Zn (193 mAh g−1, and 80% capacity retention). The PCzCNTs overlayer imparts long lifespan with nominal capacity fade, guarantees ultra-safe operation, is cost-effective and also easy to scale-up thus providing a solution that can be adapted to other metal-ion batteries free of dendrites and long term cycling stability. [Display omitted] • Poly(carbazole)-carbon nanotubes (PCz@CNTs) supresses dendrite growth at Zn anode. • PCz@CNTs protects Zn anode and allows homogeneous Zn deposition through functional groups. • Porous graphitic flakes (PGFs) prepared from puffed rice is electrically conducting. • V 6 O 13 nanorods@PGFs cathode has short ion-diffusion lengths and many sites for Zn2+ adsorption. • V 6 O 13 NRs@PGFs//PCz@CNTs@Zn delivers 286 mAh g−1 after 300 cycles at 30 mA g−1. [ABSTRACT FROM AUTHOR]

Despite the high potential impact of aqueous battery systems, fundamental characteristics such as cost, safety, and stability make them less feasible for large-scale energy storage systems. One of the main barriers encountered in the commercialization of aqueous batteries is the development of large-scale electrodes with high reversibility, high rate capability, and extended cycle stability at low operational and maintenance costs. To overcome some of these issues, the current research work is focused on a new class of material based on phenethylammonium bismuth iodide on fluorine doped SnO2-precoated glass substrate via aerosol-assisted chemical vapor deposition, a technology that is industrially competitive. The anode materials were electrochemically investigated in Zn2+ aqueous electrolytes as a proof of concept, which presented a specific capacity of 220 mAh g−1 at 0.4 A g−1 with excellent stability after 50 scans and capacity retention of almost 100%. [ABSTRACT FROM AUTHOR]

On-chip micro-supercapacitors (MSCs), as promising power candidates for microdevices, typically exhibit high power density, large charge/discharge rates, and long cycling lifetimes. However, as for most reported MSCs, the unsatisfactory areal energy density (<10 µWh cm -2 ) still hinders their practical applications. Herein, a new-type Zn-ion hybrid MSC with ultrahigh areal energy density and long-term durability is demonstrated. Benefiting from fast ion adsorption/desorption on the capacitor-type activated-carbon cathode and reversible Zn stripping/plating on the battery-type electrodeposited Zn-nanosheet anode, the fabricated Zn-ion hybrid MSCs exhibit remarkable areal capacitance of 1297 mF cm -2 at 0.16 mA cm -2 (259.4 F g -1 at a current density of 0.05 A g -1 ), landmark areal energy density (115.4 µWh cm -2 at 0.16 mW cm -2 ), and a superb cycling stability without noticeable decay after 10 000 cycles. This work will inspire the fabrication and development of new high-performance microenergy devices based on novel device design., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)