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Texturing metallic zinc anodes (MZAs) for selective exposure of (002)Zn plane with high thermodynamical stability is an efficient scheme for dendrite‐free Zn electrodeposition. However, fundamental factors that influence Zn deposition morphology via surface crystallographic texture engineering are not well understood. Herein, different from traditional cognition, MZAs with preferential exposure of (101)Zn facet are demonstrated to be equally effective in promoting dendrite‐free Zn deposition, which is enabled by introducing trace amount (0.01 m) of theophylline into ZnSO4 electrolyte. Experimental results and mathematical model corroborate, indicating mechanistically that the theophylline derived cations preferentially adsorb on the (002)Zn crystal plane due to higher adsorption energy, thereby accelerating its growth through increased binding affinity with Zn2+ ions. Consequently, this phenomenon facilitates the texture exposure of (101)Zn facet to achieve ordered surface crystallographic orientation of MZAs (101‐Zn), thus enabling electrodeposition/dissolution cycling over 650 h under a depth of discharge up to 40% and significantly boosting the rechargeability (76.7% capacity retention after 1000 cycles) of the 101‐Zn||carbon‐cloth@MnO2 full battery relative to counterpart without theophylline additive (36.3%). The work offers deep insights on the scientific links between the surface crystallographic orientation of MZAs and Zn deposition morphology, while opens up vast untapped opportunities to realize dendrite‐free MZAs. [ABSTRACT FROM AUTHOR]

Conventional MXene‐based thick electrodes with stacked and tortuous microstructures suffer from sluggish charge transport and low‐utilization of active substances, thus a limited boost in areal energy density of the assembled micro‐supercapacitors (MSCs). Herein, the duplication of wood‐like microstructure is realized in MXene/Ag‐nanowires (AgNWs) hybrid aerogel electrode (WL‐M/A‐AE) via directional freeze‐drying technique. Benefitting from the uniform 3D vertically‐aligned microchannels as the highways for ions transport throughout the matrix, the WL‐M/A‐AE with a thickness of up to 2000 µm can achieve a 50‐times higher of Cl− diffusion coefficient relative to closely restacked film electrode with the same mass loading of MXene. Furthermore, the evenly interspersed AgNWs serving as percolation network within the electrode matrix can facilitate horizontal electrons transmission between vertically‐aligned loose MXene flakes, while reversibly capture/release Cl− ions via phase conversion (Ag⇔AgCl) to raise the charge storage capacity of the WL‐M/A‐AE. Thus, when coupling with Zn anode, the assembled micro‐redoxcapacitor adopting polyacrylamide/ZnCl2+NH4Cl hydrogel electrolyte can deliver an areal energy density up to 292.5 µWh cm−2 in a more stable way (a smooth discharge plateau contributing 40.9% of the energy). The demonstrated hybrid thick electrode with wood‐like low‐tortuosity microstructure promises an effective avenue for tackling the performance bottlenecks facing traditional MSCs. [ABSTRACT FROM AUTHOR]

High iodine loading and high‐temperature adaptability of the iodine cathode are prerequisites to achieving high energy density at full battery level and promoting the practical application for the zinc‐iodine (Zn‐I2) battery. However, it would aggravate the polyiodide shuttle effect when employing high iodine loading and working temperature. Here, a sustainable cationic cellulose nanofiber (cCNF) was employed to confine the active iodine species through strong physiochemical adsorption to enlarge the iodine loading and stabilize it even at high temperatures. The cCNF could accommodate dual‐functionality by enlarging the iodine loading and suppressing the polyiodide shuttle effect, owing to the unique framework structure with abundant surface positive charges. As a result, the iodine cathode based on the cCNF could deliver high iodine mass loading of 14.1 mg cm−2 with a specific capacity of 182.7 mAh g−1, high areal capacity of 2.6 mAh cm−2, and stable cycling over 3000 cycles at 2 A g−1, thus enabling a high energy density of 34.8 Wh kg−1 and the maximum power density of 521.2 W kg−1 at a full Zn‐I2 battery level. In addition, even at a high temperature of 60 °C, the Zn‐I2 battery could still deliver a stable cycling. [ABSTRACT FROM AUTHOR]

Snorkeling equipments have played a vitally important role in various underwater operations, such as military, rescue activities, underwater research, archeology, and so on. However, existing snorkeling styles, represented by mechanical lifting system, artificial diving, and submarine mode (water storage and drainage), still face numerous challenges in the issues of large energy loss, complex structure, or environmental unfriendliness. Especially for small flexible equipments, an efficient and convenient way of snorkeling is of prime importance to various underwater explorations for a long time. Here, for the first time, an automatic snorkeling electronic equipment driven by a self‐breathing flexible aqueous aluminum‐air battery (Self‐BAAAB) which integrates functions of the snorkeling and the electric energy supply is designed. The self‐BAAAB battery consists of naturally inspired spongy sodium polyacrylate (PANa) hydrogel that acts as a flexible electrolyte and vertical N–O doped graphene fiber (NOGF) as an ORR/OER/HER trifunctional electrocatalyst. Benefited from the trifunctional catalytic properties and the aluminum metal stripping, the Self‐BAAAB consumes oxygen gas in the routine discharge process while the gas in turn is released during the charging process due to electrolysis of water in the super‐absorbing hydrogel, which triggers the sharp density variation of Self‐BAAAB, driving the "automatic snorkeling" feature of electronic equipment underwater. This work provides new insights into the design of the snorkeling electronic equipments and would promote the high efficiency of underwater operations, especially in a complex environment. [ABSTRACT FROM AUTHOR]

Supercapacitors (SCs) offer broad possibilities in the rising domain of military and civilian owing to their intrinsic properties of superior power density, long lifetime, and safety features. Despite of low‐cost, facile manufacture, and time‐saving, 3D printing technology unleashes the potential of SCs in terms of achieving desirable capacitance with high mass loading, fabrication of well‐designed complicated structures, and direct construction of on‐chip integration systems. In this review, first, the representative printing technologies for SCs and advanced printable materials are scrutinized for SCs and advanced printable materials. Then the structure design principles of electrodes and devices are respectively highlighted and reported cases are systematically summarized. Next, configurations of the SCs and their applications in various areas are described in detail. Finally, the promising research directions for the future are discussed. The perspectives reviewed here are expected to provide a comprehensive understanding of 3D‐printed SCs and guidance in realizing their promise in various applications. [ABSTRACT FROM AUTHOR]