Rechargeable alkaline zinc-air batteries promise high energy density and safety but suffer from the sluggish 4 electron (e−)/oxygen (O2) chemistry that requires participation of water and from the electrochemical irreversibility originating from parasitic reactions caused by caustic electrolytes and atmospheric carbon dioxide. Here, we report a zinc-O2/zinc peroxide (ZnO2) chemistry that proceeds through a 2e−/O2 process in nonalkaline aqueous electrolytes, which enables highly reversible redox reactions in zinc-air batteries. This ZnO2 chemistry was made possible by a water-poor and zinc ion (Zn2+)–rich inner Helmholtz layer on the air cathode caused by the hydrophobic trifluoromethanesulfonate anions. The nonalkaline zinc-air battery thus constructed not only tolerates stable operations in ambient air but also exhibits substantially better reversibility than its alkaline counterpart.

Here, we bring to the readers the outcome of Group 1 discussion: Future after lithium. The group has covered battery chemistries that are often being considered as "post-Li" battery technologies. After extensive deliberations, the group concluded that the current vibe about the need of future technologies after the lithium era and, thus, the quest for which new technologies can replace lithium-based battery technology, are somewhat inappropriate and misleading (partially incorrect), respectively. The discussion group reached the conclusion that it would be wise to approach and refer at these technologies as "side-byside" to Li-based batteries. As such, we elaborate here in details on these "side-by-side" promising technologies.Evaluation of the battery concepts depends on several aspects, among which performance is one of the key parameters. Hence, the performance comparison of different cell chemistry is everything, but immediate. As a matter of the fact, the European Commission, e.g., funded the ETIP Batteries Europe (https:// batterieseurope.eu/) as the "one-stop shop" for the batteryrelated R&I ecosystem and aims to accelerate the establishment of a competitive, sustainable and efficient value chain and globally competitive European battery industry through Research and Innovation. Within this ETIP, several working groups have been established, including the one dealing with new and emerging cell technologies. This group, led by Prof. Edström, Dr. Steven and one of the co-authors of this manuscript (SP), is expected to identify the key performance indicators (KPIs) enabling a fair comparison of commercial, new and emerging cell technologies with respect to their applications. However, these KPIs have not been identified yet. Hence, the current study aims to provide insights into "side-by-side" new emerging technologies and also to report a comparative analysis to Li-ion batteries by using a simple approach (i.e., mainly considering cost, energy density, and cycle life). Nonetheless, due to the fact that most of the "side-by-side" technologies are at the early stage of development, a comparison among them is not trivial. Thus, we point out in this progress report only the possibly suitable applications of the new technologies without a comparison. Sodium-Ion Batteries (Na-Ion) IntroductionTo relieve the environmental issues, solving the problem caused by intermittent availability of renewable energy resource, e.g., solar energy, wind energy and geothermal energy, is mandatory. Thus, energy storage systems, especially electrochemical energy storage (EES) systems including batteries, supercapacitors, etc., are in the focus of intensive research and development efforts. [1][2][3] In 1991, the Japanese Sony Corp. developed the first commercial lithium-ion batteries with LiCoO 2 and graphite as electrode materials. [4,5] With the blooming of portable electronic Yasin Emre Durmus is currently a PostDoc researcher at the Forschungszentrum Jülich (Germany) within the Institute of Fundamental Electrochemistry (IEK-9). ...

Organic materials are promising candidates for next-generation battery systems. However, many organic battery materials suffer from high solubility in common battery electrolytes. Such solubility can be overcome by introducing tailored high-molecular-weight polymer structures, for example, by crosslinking, requiring enhanced synthetic efforts. We herein propose a different strategy by optimizing the battery electrolyte to obtain insolubility of non-cross-linked poly(3-vinyl-N-methylphenothiazine) (PVMPT). Successive investigation and theoretical insights into carbonate-based electrolytes and their interplay with PVMPT led to a strong decrease in the solubility of the redox polymer in ethylene carbonate/ethyl methyl carbonate (3:7) with 1 M LiPF 6 . This allowed accessing its full theoretical specific capacity by changing the charge/discharge mechanism compared to previous reports. Through electrochemical, spectroscopic, and theoretical investigations, we show that changing the constituents of the electrolyte significantly influences the interactions between the electrolyte molecules and the redox polymer PVMPT. Our study demonstrates that choosing the ideal electrolyte composition without chemical modification of the active material is a successful strategy to enhance the performance of organic polymer-based batteries.