An ultrasmall structure-optimized vanadium oxides integrated into nitrogen-doped bead-chain-like hollow carbon nanofibers for advanced flexible cathode of zinc ion batteries.

With the rapid advancement of science and technology, rechargeable aqueous zinc ion batteries (AZIBs) has garnered increasing attention in consideration of security, chemical stability and cost-effectiveness. Vanadium-based oxides have emerged as a promising high-performance electrode materials for AZIBs, owing to their high energy density, rich crystal configurations, and simple preparation process. However, the practical application of vanadium oxides is hindered by their low ion/electron transfer rate and significant capacity fading during electrochemical reactions.

High-Performance Bipolar Small-Molecule Organic Cathode for Wide-Temperature-Range Aqueous Zinc-Ion Batteries.

Organic small-molecules with redox activity are promising cathode candidates for aqueous zinc-ion batteries (AZIBs) due to their low cost, high safety and high theoretical capacity. However, their severe dissolution leads to unsatisfactory electrochemical performance. Here, a dihydro-octaaza-pentacene (DOP) compound is synthesized as a cathode for AZIBs by extending its N heterocyclic molecular structure.

Nickel-Doping Induced Oxygen Vacancies in MnO Hollow Cube with Enlarged Interlayer Spacing for Stable Sodium Ions Storage.

Intrinsic low conductivity, poor structural stability, and narrow interlayer spacing limit the development of MnO in sodium-ion (Na) supercapacitors. This work constructs the hollow cubic Mn-PBA precursor through an ion-exchange process to in situ obtain a hollow cubic H-Ni-MnO composite with Ni doping and oxygen vacancies (O) via a self-oxidation strategy. Experiments and theoretical calculations show that the hollow nanostructure and the expanding interlayer spacing induced by Ni doping are beneficial for exposing more reactive sites, synergistically manipulating the Na transport pathways.

Tailoring hierarchical MnO nanostructures on self-supporting cathodes for high-mass-loading zinc-ion batteries.

Aqueous zinc-ion batteries (AZIBs) with MnO cathodes have promising application prospects; however, their performance is hindered by their low efficiency and insufficient life. By leveraging the nanomicellar properties of cetyltrimethylammonium bromide (CTAB), a hierarchical δ-MnO with 2D/3D structure was directionally grown on a modified carbon cloth (CC) collector for realizing high-mass-loading AZIBs. Experimental results reveal the synergistic effects of micro/nano hierarchically structured MnO-CC heterointerfaces in accelerating the electron migration and transfer rate of Zn/H.

Advanced cathodes for aqueous Zn batteries beyond Zn intercalation.

Aqueous zinc (Zn) batteries have attracted global attention for energy storage. Despite significant progress in advancing Zn anode materials, there has been little progress in cathodes. The predominant cathodes working with Zn/H intercalation, however, exhibit drawbacks, including a high Zn diffusion energy barrier, pH fluctuation(s) and limited reproducibility.

Low-cost and Non-flammable Eutectic Electrolytes for Advanced Zn-I Batteries.

As a burgeoning electrolyte system, eutectic electrolytes based on ZnCl /Zn(CF SO ) /Zn(TFSI) have been widely proposed in advanced Zn-I batteries; however, safety and cost concerns significantly limit their applications. Here, we report new-type ZnSO -based eutectic electrolytes that are both safe and cost-effective. Their universality is evident in various solvents of polyhydric alcohols, in which multiple -OH groups not only involve in Zn solvation but also interact with water, resulting in the high stability of electrolytes.

Understanding H Evolution Electrochemistry to Minimize Solvated Water Impact on Zinc-Anode Performance.

H evolution is the reason for poor reversibility and limited cycle stability with Zn-metal anodes, and impedes practical application in aqueous zinc-ion batteries (AZIBs). Here, using a combined gas chromatography experiment and computation, it is demonstrated that H evolution primarily originates from solvated water, rather than free water without interaction with Zn . Using linear sweep voltammetry (LSV) in salt electrolytes, H evolution is evidenced to occur at a more negative potential than zinc reduction because of the high overpotential against H evolution on Zn metal.

Triple-Function Electrolyte Regulation toward Advanced Aqueous Zn-Ion Batteries.

The poor Zn reversibility has been criticized for limiting applications of aqueous Zn-ion batteries (ZIBs); however, its behavior in aqueous media is not fully uncovered yet. Here, this knowledge gap is addressed, indicating that Zn electrodes face a O -involving corrosion, besides H evolution and dendrite growth. Differing from aqueous Li/Na batteries, removing O cannot enhance ZIB performance because of the aggravated competing H evolution.

Studying the Conversion Mechanism to Broaden Cathode Options in Aqueous Zinc-Ion Batteries.

Aqueous Zn-ion batteries (ZIBs) are regarded as alternatives to Li-ion batteries benefiting from both improved safety and environmental impact. The widespread application of ZIBs, however, is compromised by the lack of high-performance cathodes. Currently, only the intercalation mechanism is widely reported in aqueous ZIBs, which significantly limits cathode options.

Boosting Zinc Electrode Reversibility in Aqueous Electrolytes by Using Low-Cost Antisolvents.

Antisolvent addition has been widely studied in crystallization in the pharmaceutical industries by breaking the solvation balance of the original solution. Here we report a similar antisolvent strategy to boost Zn reversibility via regulation of the electrolyte on a molecular level. By adding for example methanol into ZnSO electrolyte, the free water and coordinated water in Zn solvation sheath gradually interact with the antisolvent, which minimizes water activity and weakens Zn solvation.

Bio-templated fabrication of three-dimensional network activated carbons derived from mycelium pellets for supercapacitor applications.

In this work, a three-dimensional porous mycelium-derived activated carbon (3D-MAC) was fabricated via a facile bio-templating method using mycelium pellets as both the carbon source and the bio-template. After ZnCl activation and high-temperature carbonization, the specific thread-like chain structure of mycelium in the pellets can be maintained effectively. The hyphae and junctions of the cross-linking hyphae form nanowires and carbon nanoparticles that link with the neighboring nanoparticles to form a network structure.