Fall and Rise: Disentangling Cycle Life Trends in Atmospheric Plasma-Synthesized FeOOH/PANI Composite for Conversion Anodes in Lithium-Ion Batteries

Various iron oxides have been proven to be promising anode materials for metal-ion batteries due to their natural abundance, high theoretical capacity, ease of preparation, and environmental friendliness. However, the synthesis of iron oxide-based composites requires complex approaches, especially when it comes to composites with intrinsically conductive polymers. In this work, we propose a one-step microplasma synthesis of polyaniline-coated urchin-like FeOOH nanoparticles (FeOOH/PANI) for applications as anodes in lithium-ion batteries. The material shows excellent electrochemical properties, providing an initial capacity of ca. 1600 mA∙h∙g−1 at 0.05 A∙g−1 and 900 mA∙g−1 at 1.2 A∙g−1. Further cycling led to a capacity decrease to 150 mA∙h∙g−1 by the 60th cycle, followed by a recovery that maintained the capacity at 767 mA∙h∙g−1 after 2000 cycles at 1.2 A∙g−1 and restored the full initial capacity of 1600 mA∙h∙g−1 at a low current density of 0.05 A∙g−1. Electrochemical milling—the phenomenon we confirmed via a combination of physico-chemical and electrochemical techniques—caused the material to exhibit interesting behavior. The anodes also exhibited high performance in a full cell with NMC532, which provided an energy density of 224 Wh∙kg−1, comparable to the reference cell with a graphite anode (264 Wh∙kg−1)

Vanadium Oxide-Poly(3,4-ethylenedioxythiophene) Nanocomposite as High-Performance Cathode for Aqueous Zn-Ion Batteries: The Structural and Electrochemical Characterization

In this work the nanocomposite of vanadium oxide with conducting polymer poly(3,4-ethylenedioxythiophene) (VO@PEDOT) was obtained by microwave-assisted hydrothermal synthesis. The detailed study of its structural and electrochemical properties as cathode of aqueous zinc-ion battery was performed by scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction analysis, X-ray photoelectron spectroscopy, thermogravimetric analysis, cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The initial VO@PEDOT composite has layered nanosheets structure with thickness of about 30–80 nm, which are assembled into wavy agglomerated thicker layers of up to 0.3–0.6 μm. The phase composition of the samples was determined by XRD analysis which confirmed lamellar structure of vanadium oxide V10O24∙12H2O with interlayer distance of about 13.6 Å. The VO@PEDOT composite demonstrates excellent electrochemical performance, reaching specific capacities of up to 390 mA∙h∙g−1 at 0.3 A∙g−1. Moreover, the electrodes retain specific capacity of 100 mA∙h∙g−1 at a high current density of 20 A∙g−1. The phase transformations of VO@PEDOT electrodes during the cycling were studied at different degrees of charge/discharge by using ex situ XRD measurements. The results of ex situ XRD allow us to conclude that the reversible zinc ion intercalation occurs in stable zinc pyrovanadate structures formed during discharge