We report the chemical intercalation of Li+ into the interlayer of V2O5·nH2O with enlarged layer spacing and fast Zn2+ diffusion, resulting in high rate capability and excellent long-term cycling performance.

No abstract

No abstract

Aqueous Zn–MnO2 batteries have received much attentions for large‐scale applications because of high safety and low cost. However, the energy storage mechanisms of Zn–MnO2 system are still in dispute. Herein, a cathode‐free Zn–MnO2 battery is provided with the coexistence of dual mechanisms in mild acidic environment, in which the decisive guiding effect of the pH value in electrolyte on the mechanism is deeply investigated. On this basis, acetic acid (HAc) is used as a buffering additive to effectively suppress the “fluctuation” phenomenon during the operation, hence achieving the “self‐adjust” mechanism. The assembled soft package battery possesses a long lifetime of 2000 cycles with the Coulombic efficiency of 99.6%, improved high‐loading performance and rate capability. A new idea is provided for the exploration of energy storage mechanism of Zn–MnO2 battery as well as a guidance on the optimization strategies especially the battery construction.

A eutectic electrolyte strategy is proposed for zinc-iodine battery. Both the reasonable solvated structure and suppressed generation of I3− as an intermediate product achieve the high reversible I−/I0 conversion.

Biphasic and multiphasic compounds have been well clarified to achieve extraordinary electrochemical properties as advanced energy storage materials. Yet the role of phase boundaries in improving the performance is remained to be illustrated. Herein, we reported the biphasic vanadate, that is, Na1.2V3O8/K2V6O16·1.5H2O (designated as Na0.5K0.5VO), and detected the novel interfacial adsorption–insertion mechanism induced by phase boundaries. First‐principles calculations indicated that large amount of Zn2+ and H+ ions would be absorbed by the phase boundaries and most of them would insert into the host structure, which not only promote the specific capacity, but also effectively reduce diffusion energy barrier toward faster reaction kinetics. Driven by this advanced interfacial adsorption–insertion mechanism, the aqueous Zn/Na0.5K0.5VO is able to perform excellent rate capability as well as long‐term cycling performance. A stable capacity of 267 mA h g−1 after 800 cycles at 5 A g−1 can be achieved. The discovery of this mechanism is beneficial to understand the performance enhancement mechanism of biphasic and multiphasic compounds as well as pave pathway for the strategic design of high‐performance energy storage materials.

Highlights We first report on H 11 Al 2 V 6 O 23.2 with large layer spacing as cathode for aqueous zinc-ion battery, which accelerates the diffusion of Zn 2+ . The graphene-wrapped H 11 Al 2 V 6 O 23.2 nanobelts can improve electronic conductivity, and potentially inhibit the dissolution of elements in the aqueous electrolyte. H 11 Al 2 V 6 O 23.2 @graphene exhibits high capacity and stable cycling stability even at an ultra-high mass loading of ~ 15.7 mg cm −2 . Electronic supplementary material The online version of this article (10.1007/s40820-019-0300-2) contains supplementary material, which is available to authorized users.

The irregular and random electrodeposition of zinc has emerged as a non‐negligible barrier for deeply rechargeable aqueous zinc (Zn)‐ion batteries (AZIBs), yet traditional texture regulation of the Zn substrate cannot continuously induce uniform Zn deposition. Here, a Janus separator is constructed via parallelly grown graphene sheets modified with sulfonic cellulose on one side of the commercial glass fiber separator through the spin‐coating technique. The Janus separator can consistently regulate Zn growth toward a locked crystallographic orientation of Zn(002) texture to intercept dendrites. Furthermore, the separator can spontaneously repel SO42− and anchor H+ while allowing effective transport of Zn2+ to alleviate side reactions. Accordingly, the Zn symmetric cell harvests a long‐term lifespan over 1400 h at 10 mA cm−2/10 mAh cm−2 and endures stable cycling over 220 h even at a high depth of discharge (DOD) of 56%. The Zn/carbon nanotube (CNT)–MnO2 cell achieves an outstanding capacity retention of 95% at 1 A g−1 after 1900 cycles. Furthermore, the Zn/NH4V4O10 pouch cell with a Janus separator delivers an initial capacity of 178 mAh g−1 and a high capacity retention of 87.4% after 260 cycles. This work provides a continuous regulation approach to achieve crystallographic homogeneity of the Zn anode, which can be suitable for other metal batteries.