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Improving the efficiency of bifunctional electrocatalysts is a decisive challenge in the area of long‐lasting rechargeable zinc‐air batteries. Enhancing the catalysts' performance is crucial for advancing zinc‐air batteries. Transition‐metal oxides have emerged as promising non‐precious, noble‐metal‐free catalysts. Herein, a unique precursor directed approach is introduced for preparing a cobalt ferrite@nitrogen doped carbon nanohorns (CoFe2O4@N‐CNHs) nanohybrid catalyst in a single step annealing process involving stoichiometric amounts of single‐source cobalt and iron molecular precursors and carbon nanohorns (CNHs) under an argon/ammonia (Ar/NH3) atmosphere. This procedure enables a simultaneous CoFe2O4 ferrite synthesis and nitrogen functionalization of CNHs. The precious metal free nanohybrid CoFe2O4@N‐CNHs‐30% containing 30% of carbon presents an oxygen reduction reaction (ORR) half wave potential and onset potential comparable to the standard ORR catalyst 20% Pt/C. CoFe2O4@N‐CNHs‐30% also establishes superior oxygen evolution reaction (OER) performance with a low overpotential and a small Tafel slope than benchmark OER catalyst RuO2. Furthermore, the rechargeable zinc‐air battery with the CoFe2O4@N‐CNHs‐30% nanohybrid as air electrode demonstrates steadier and more durable charge–discharge cycles, and outstanding energy density relative to the state‐of‐the‐art 20% Pt/C‐RuO2 catalyst. [ABSTRACT FROM AUTHOR]

Lithium-thiophosphate-based all-solid-state batteries (ASSBs) are increasingly attracting attention for high-density electrochemical energy storage. In this work, the cycling performance of single and polycrystalline forms of LiNixCoyMnzO2 (NCM, with =83% Ni content) cathode active materials in ASSB cells with an Li4Ti5O12 composite anode is explored, and the advantages and disadvantages of both morphologies are discussed. The virtual lack of grain boundaries in the quasi-single-crystalline material is found to contribute to improved stability by eliminating the tendency of Ni-rich NCM particles to crack during cycling, due to volume differences between the lithiated and delithiated phases. Although the higher crack resistance mitigates effects of chemical oxidation of the lithium thiophosphate solid electrolyte, the cells suffer from electrochemical side reactions occurring at the cathode interfaces. However, coating the single-crystal particles with a protective LiNbO3 overlayer helps to stabilize the interface between cathode active material and solid electrolyte, leading to a capacity retention of 93% after 200 cycles (with qdis? 160 mAh gNCM -1 or1.7 mAh cm-2 at C/5 rate and 45 °C). Overall, this work highlights the importance of addressing electro-chemo-mechanical phenomena in ASSB electrodes. [ABSTRACT FROM AUTHOR]

Magnesium–Sulfur batteries are one of most appealing options among the post‐lithium battery systems due to its potentially high energy density, safe and sustainable electrode materials. The major practical challenges are originated from the soluble magnesium polysulfide intermediates and their shuttling between the electrodes, which cause high overpotentials, low sulfur utilization, and poor Coulombic efficiency. Herein, a functional Mo6S8 modified separator is designed to effectively address these issues. Both the experimental results and density functional theory calculations show that the electrochemically active Mo6S8 layer has a superior adsorption capability of polysulfides and simultaneously acts as a mediator to accelerate the polysulfide conversion kinetics. Remarkably, the magnesium–sulfur cell assembled with the functional separator delivers a high specific energy density (942.9 mA h g−1 in the 1st cycle) and can be cycled at 0.2 C for 200 cycles with a Coulombic efficiency of 96%. This work demonstrates a new design concept toward high‐performance metal–sulfur batteries. [ABSTRACT FROM AUTHOR]

Upon immersion of a lithium (Li) anode into a diluted 0.05 to 0.20 M dimethoxyethane‐solution of the phosphoric acid derivative (CF3CH2O)2P(O)OH (HBFEP), an artificial solid electrolyte interphase (SEI) is generated on the Li‐metal surface. Hence, HBFEP reacts on the surface to the corresponding Li salt (LiBFEP), which is a Li‐ion conducting inorganic coordination polymer. This film exhibits – due to the reversibly breaking ionic bonds – self‐healing ability upon cycling‐induced volume expansion of Li. The presence of LiBFEP as the major component in the artificial SEI is proven by ATR‐IR and XPS measurements. SEM characterization of HBFEP‐treated Li samples reveals porous layers on top of the Li surface with at least 3 μm thickness. Li−Li symmetrical cells with HBFEP‐modified Li electrodes show a three‐ to almost fourfold cycle‐lifetime increase at 0.1 mA cm−2 in a demanding model electrolyte that facilitates fast battery failure (1 M LiOTf in TEGDME). Hence, the LiBFEP‐enriched layer apparently acts as a Li‐ion conducting protection barrier between Li and the electrolyte, enhancing the rechargeability of Li electrodes. [ABSTRACT FROM AUTHOR]

The study of an artificial solid‐electrolyte interphase (SEI) can lead to a misinterpretation of the electrochemical results obtained with the classical cell configuration due to so‐called edge effect. A technical solution is presented here that minimizes the edge effect by using a new cell configuration with a polypropylene disc. A new cell configuration allows a simple electrochemical evaluation of an artificial SEI with a more precisely defined effective area and homogeneously distributed current density. The application of such a technical solution manifests itself through better defined deposition and stripping curves in relation to surface electrochemistry and can differ significantly from the results obtained with the classical cell configuration. Finally, a model system ‐ a lithium electrode protected with trimethylolpropane ethoxylate triacrylate polymer‐was used to evaluate and compare the new cell configuration with the classical two electrode cell configuration. [ABSTRACT FROM AUTHOR]

Lithium–Sulfur (Li–S) batteries are promising energy storage devices due to their high theoretical energy density. However, challenges such as the shuttling effect and volume expansion have significantly hindered their cycle life and capacity retention. Furthermore, the complex kinetic pathways in Li–S batteries call for advanced characterization techniques to unravel underlying mechanisms. In this study, a hollow porous carbon (HPC) is used as a microreactor, where inverse vulcanization occurs between 1,3‐diisopropylbenzene (DIB) and sulfur (S8), resulting in the creation of three‐dimensionally interconnected and well‐distributed S‐DIB in carbon frameworks. As a result, the dual confinement strategy imparts Li–S coin cells with remarkable cycling stability and capacity retention, exhibiting an impressive capacity of 866 mAh g−1 when returning to 0.1 C after 100 cycles of rate capability tests. Particularly, the Energy‐selective Backscattered (EsB) assisted Scanning Electron Microscope (SEM) technique as a novel approach is introduced to distinguish different lengths of polysulfides. Their distribution is visualized in the cross‐section view of the electrode in a micrometer range. These EsB images provide concrete indications of the sulfur evolution process and explain the capacity degradation during cycling. [ABSTRACT FROM AUTHOR]

Photoelectron spectroscopy (PES) studies of solid electrolyte interphases (SEI) of cycled battery electrodes are mostly performed in half cell configurations (i.e., against metallic counter electrodes). In contrast to less reactive Li metal, problems arise in post‐Li systems, like K‐ion cells, where crosstalk phenomena strongly interfere with the surface layer formation process. This raises the question of whether surface analysis data from half cell experiments are still representative and transferable to corresponding full cells in post‐Li systems. Here the major differences between SEI layers formed on graphite electrodes are outlined in K‐ion half and full cells derived from an in‐depth surface analysis approach combining in‐house and (synchrotron‐based) hard X‐ray PES. This results highlight significant changes in SEI characteristics, both in terms of SEI layer thickness and gradual compositional changes across the interphase, when K‐metal (half cell) is replaced by a Prussian white positive electrode (full cell). Furthermore, the initial SEI layers formed on the first cycle are found to evolve and age differently upon further cycling, depending on the two cell configurations. This study stresses the additional complexity of studying post‐Li cells and the need to carefully design surface analysis experiments for meaningful material and electrode interphase characterization. [ABSTRACT FROM AUTHOR]