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Aqueous zinc‐bromine batteries represent a promising large‐scale energy storage system, yet generally suffer from the dissolution of polybromides in the cathode. Currently, various nonpolar carbon materials are employed as hosts for the bromine cathode. Still, they typically exhibit weak adsorption capabilities toward polybromides. Here, a highly conductive Ti2CTx MXene synthesized through an eco‐friendly molten salt method is reported, serving as an ideal bromine cathode host material for the first time. Ti2CTx MXene shows strong chemisorptive capability to soluble polybromide species and can effectively immobilize them for enhanced coulombic efficiency and prolong cycling life of zinc‐bromine batteries. Additionally, Ti2CTx MXene enhances the reaction kinetics of the bromine cathode. Benefiting from the synergistic polybromide adsorption and catalysis effects of Ti2CTx, the dual‐plating zinc‐bromine batteries exhibit good cycle stability, with a capacity retention of 87% after 3000 cycles, outperforming traditional carbon host which fail after 2300 cycles. Meanwhile, Ti2CTx achieves a much lower polarization voltage of only 84 mV, significantly less than 240 mV observed with carbon hosts. This research highlights the potential of developing host materials with polybromide chemisorptive properties to advance the performance of zinc‐bromine batteries. [ABSTRACT FROM AUTHOR]

Currently, limited by factors such as low working voltage (≤1 V), poor temperature tolerance, and underutilization of electrolytes, pure aqueous symmetric planar microsupercapacitors (PMSCs) show unsatisfactory energy density under wide temperature ranges. To address these issues, a novel strategy is introduced to construct pure aqueous PMSCs with an ultrahigh energy density under wide temperature ranges through the development of high‐performance carbon nanotube‐MnO2 microelectrodes and high‐voltage aqueous polyacrylamide polyelectrolyte with exceptional temperature tolerance and redox‐enhanced function. Notably, the capacitance contribution of alizarin red S redox additives and the outstanding ability to withstand high voltage of polyacrylamide polyelectrolyte play the crucial roles in improving the electrochemical performance of PMSCs. As a result, the constructed microdevice achieves a record‐high working voltage of 2 V at temperatures from −15 °C to 100 °C and ultrahigh areal energy densities of 12.9 μWh cm–2 at −15 °C, 17.4 μWh cm–2 at room temperature and 24 μWh cm–2 at 100 °C, which are superior to those of previously reported pure aqueous PMSCs at the temperature. Meanwhile, it also shows good flexibility and excellent cycling stability (92.7% after 25 000 cycles at −15 °C and 81% after 20 000 cycles at 100 °C). [ABSTRACT FROM AUTHOR]

The construction of single‐atom catalysts (SACs) with high single atom densities, favorable electronic structures and fast mass transfer is highly desired. We have utilized metal‐triazolate (MET) frameworks, a subclass of metal–organic frameworks (MOFs) with high N content, as precursors since they can enhance the density and regulate the electronic structure of single‐atom sites, as well as generate abundant mesopores simultaneously. Fe single atoms dispersed in a hierarchically porous N‐doped carbon matrix with high metal content (2.78 wt %) and a FeN4Cl1 configuration (FeN4Cl1/NC), as well as mesopores with a pore:volume ratio of 0.92, were obtained via the pyrolysis of a Zn/Fe‐bimetallic MET modified with 4,5‐dichloroimidazole. FeN4Cl1/NC exhibits excellent oxygen reduction reaction (ORR) activity in both alkaline and acidic electrolytes. Density functional theory calculations confirm that Cl can optimize the adsorption free energy of Fe sites to *OH, thereby promoting the ORR process. The catalyst demonstrates great potential in zinc‐air batteries. This strategy selects, designs, and adjusts MOFs as precursors for high‐performance SACs. [ABSTRACT FROM AUTHOR]

Symmetric aqueous microsupercapacitors (MSCs) generally show a low working voltage (≤1 V) and narrow operating temperature window in the vicinity of 25 °C due to the poor temperature tolerance and instability of conventional aqueous electrolytes under high voltage. It is challenging to develop MSCs that can offer a high‐voltage output (>2 V) under complex ambient temperature. In this work, a symmetric MSC is fabricated by using the anti‐freezing and heat‐tolerant aqueous polyacrylamide polyelectrolyte (HVTT‐PAM‐10.5) and carbon nanotube microelectrodes, which achieves a record high output voltage of 2.3 V and the widest operating temperature window of −40 to 100 °C among the aqueous MSCs reported previously. It can deliver an ultrahigh areal energy density of above 4.9 μWh cm−2 at temperatures from −40 to 100 °C, outperforming the previous carbon‐based MSCs with aqueous electrolytes at room temperature. Additionally, even after 324 000 cycles at −40 °C and 10 000 cycles at 100 °C, the MSC still retains the high capacitance retention of 92.6% and 90.4%, respectively. Impressively, the HVTT‐PAM‐10.5 polyelectrolyte can also be paired with other electrode materials such as CNT/polyaniline to obtain the highest energy density of 48.6 μWh cm−2 among all symmetric/asymmetric MSCs with aqueous electrolytes. [ABSTRACT FROM AUTHOR]

Flexible aqueous rechargeable batteries that integrate excellent mechanical flexibility and reliable safety hold a great promise for next‐generation wearable electronics. Unfortunately, currently available options are unsatisfactory due to their low specific capacity, limited energy density, and unstable voltage output. Herein, to overcome these challenges, high theoretical specific capacity zinc and sulfur as the anode and cathode are selected, respectively. Furthermore, a strategy is proposed, that decoupling charge carriers in anolyte and catholyte to simultaneously endow the zinc anode and sulfur cathode with optimal redox chemistry, maximizes the energy storage of flexible aqueous batteries. The new zinc–sulfur hybrid battery possesses merits of ultrahigh theoretical specific capacity (3350 mAh gS−1) and volumetric energy density (3868 Wh L−1), low cost, ecofriendliness, and ease of fabrication and is a promising next‐generation aqueous energy storage system. The fabricated flexible aqueous zinc–sulfur hybrid battery delivers a stable output voltage (release 92% of its full capacity within a small voltage drop of 0.15 V) and an ultrahigh reversible capacity of 2063 mAh gS−1 at 100 mA gS−1, thus setting a new benchmark for flexible aqueous batteries and is promising to play a part in future flexible electronics. [ABSTRACT FROM AUTHOR]

The emerging flexible electronic devices have stimulated the development of flexible batteries, in which flexible electrodes are indispensable components. Graphene, known for its excellent electrical conductivity and mechanical stability, can be used as an ideal flexible substrate. Recently, many efforts have been devoted to graphene‐based electrodes for flexible batteries. Herein, this review summarizes recent advances in the development of graphene‐based electrodes for various flexible batteries, including metal‐ion batteries (ions of Li, Na, Zn, Al, etc.), lithium‐sulfur batteries, and metal‐air batteries (Li‐ and Zn‐air batteries). Besides, major challenges and future developments of flexible batteries are also discussed. [ABSTRACT FROM AUTHOR]

A nitrogen‐doped hierarchical porous carbon sponge, used as a matrix for tellurium accommodation, was designed and prepared in this work. The porosity of the matrix played an important role in enhancing the electrochemical performance of Li/Na–Te batteries. Specifically, the mesopores could accommodate active materials whereas the macropores provided sufficient space for partial Te accommodation and volume expansion in discharge. In addition, N heteroatoms in carbon species could enhance the electrical conductivity and widen its application in lithium/sodium storage. The monolithic and flaky architecture of the nitrogen‐doped hierarchical porous carbon sponge/tellurium composite offered a highly conductive network for fast electron transportation. As a result, the nitrogen‐doped hierarchical porous carbon sponge/tellurium composite achieved a superior rate performance for Li–Te and Na–Te batteries. Sponge it up: A nitrogen‐doped porous carbon sponge (NPCS) with monolithic architecture is used to host Te, and its electrochemical performance for Li/Na–Te batteries is investigated. Nitrogen doping facilitates the adsorption of polytellurides and improves the electrical conductivity during cycling, whereas the monolithic architecture can shorten the pass distance for electron transportation, thus greatly lowering the resistance for Li/Na storage. [ABSTRACT FROM AUTHOR]

Abstract: Double‐shelled NiO‐NiCo2O4 heterostructure@carbon hollow nanocages as efficient sulfur hosts are synthesized to overcome the barriers of lithium–sulfur (Li–S) batteries simultaneously. The double‐shelled nanocages can prevent the diffusion of lithium polysulfides (LiPSs) effectively. NiO‐NiCo2O4 heterostructure is able to promote polysulfide conversion reactions. Furthermore, the thin carbon layer outside can improve the electrical conductivity during cycling. Besides, such unique double‐shelled hollow nanocage architecture can also accommodate the volumetric effect of sulfur upon cycling. As a result, the prepared S/NiO‐NiCo2O4@carbon (C) electrode exhibits good rate capacities and stable cycling life up to 500 cycles at 0.5 C with a very low capacity decay rate of only ≈0.059% per cycle. [ABSTRACT FROM AUTHOR]

Abstract: The practical application of lithium‐sulfur (Li‐S) batteries remains remote because of rapid capacity fade caused by the low conductivity of sulfur, dissolution of intermediate lithium polysulfides, severe volumetric expansion, and slow redox kinetics of polysulfide intermediates. Here, to address these obstacles, a new sulfiphilic and highly conductive honeycomb‐like spherical cathode host constructed from hollow metallic and polar Co9S8 tubes is designed. Co9S8 can effectively bind polar polysulfides for prolonged cycle life, due to the strong chemisorptive capability for immobilizing the polysulfide species. The hollow structure, as the sulfur host, can further prevent polysulfide dissolution and offer sufficient space to accommodate the necessary volume expansion. Well‐aligned tubular arrays provide a conduit for rapid conduction of electrons and Li‐ions. More importantly, the experimental results and theoretical calculations show that Co9S8 plays an important catalytic role in improving the electrochemical reaction kinetics. When used as cathode materials for Li–S batteries, the S@Co9S8 composite cathode exhibits high capacity and an exceptional stable cycling life demonstrated by tests of 600 cycles at 1 C with a very low capacity decay rate of only ≈0.026% per cycle. [ABSTRACT FROM AUTHOR]

Zn-S Hybrid Batteries: Maximizing Energy Storage of Flexible Aqueous Batteries through Decoupling Charge Carriers (Adv. Decoupling charge carriers, flexible aqueous batteries, ultrahigh capacity, zinc-sulfur hybrid batteries Keywords: decoupling charge carriers; flexible aqueous batteries; ultrahigh capacity; zinc-sulfur hybrid batteries EN decoupling charge carriers flexible aqueous batteries ultrahigh capacity zinc-sulfur hybrid batteries 1 1 1 04/19/21 20210415 NES 210415 In article number 2003982, Zhipan Zhang, Liangti Qu, and co-workers decouple charge carriers in opposite electrodes to construct a new flexible aqueous Zn-S hybrid battery with ultrahigh specific capacity. [Extracted from the article]

To address the challenge of low discharge platforms (<1.5 V) in aqueous zinc‐based batteries, highly concentrated salts have been explored due to their wide electrochemical window (~3 V). However, these electrolytes mainly prevent hydrogen evolution and dendrite growth at the anode without significantly enhancing voltage performance. Herein we introduce an approach by adjusting solvent polarity to regulate cation solvation sheaths in hybrid electrolytes, reducing Zn/Zn2+ oxidation potential and water activity. Through strong cation‐water coordination and hydrogen bonding between dimethylsulfoxide and water, the designed electrolyte, at a low concentration, achieves a broader electrochemical window (4 V) than conventional concentrated electrolytes. Using this electrolyte, a Zn/Zn battery showed an impressive cycle life of 4340 cycles, while a Zn/lithium manganate battery delivered a high discharge platform of over 1.9 V with exceptional cycling stability. A Zn‐based micro‐battery with a polyvinyl alcohol‐based hybrid electrolyte also achieved a record‐high discharge platform of 1.94 V. This work presents a promising strategy for developing low‐concentration electrolytes for high‐performance sustainable energy storage. [ABSTRACT FROM AUTHOR]