Biodegradable Zn-ion battery with a lignin composite electrode and bio-ionic liquid based electrolyte: Possible: In situ energy generation by lignin electrocatalysis

Copyright © 2021 The Author(s). Electrochemical energy storage with lignin-based composite electrodes offers a cheap and renewable source for batteries. Lignin composites have mainly been used in supercapacitors and little has been investigated related to applying these composites in batteries. Here we show a biodegradable hybrid Zn-ion battery with a polymer/lignin composite electrode as a cathode, a Zn anode and bio-ionic liquid electrolytes. Interestingly, the polymer/lignin composite cathode led to a higher discharge capacity compared to the charge capacity over the entire 100 charge/discharge cycling process. It was observed that the lignin concentration in the composite polymer electrode was crucial in obtaining such a phenomenon. Using SEM, electrochemical analysis and NMR, we showed that lignin electrocatalytically oxidizes during battery charging, which produced the extra energy. This results in obtaining a higher discharge capacity compared to the charge capacity. It is anticipated that such an electrocatalytic technique can be extended to other battery systems to harness clean electrochemical energy from biomass.BMBF project ZIB 03XP0204

Ionic Liquids: Potential Electrolytes for Electrochemical Applications

Ionic Liquids: Potential Electrolytes for Electrochemical Application

Polymer-induced metal diffusion during plastic processing: A reason for deposit formation

In the plastic-processing industry, the formation of unknown deposits at the interface between polymer melt and steel surfaces can pose major challenges, which occurs especially on screws, barrels, and tools. These deposits will detach during production and lead to quality restrictions mostly as spots in the products. We investigated the interactions between tool steel and polymer melt, especially polycarbonate, in the early stages of deposit formation. Steel-polymer-composite samples are prepared close to the realistic conditions in the plastic-processing industry. To get further insight, thin polymer films on tool steel specimens and its alloy elements, representing model systems, are prepared. X-ray-photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) are used to characterize the interfaces chemically. Additionally, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used. We found iron and chromium diffusion into the polycarbonate melt induced by polymer metal interaction. Iron and polymer chains are immobilized at the interface by a chemical interaction, while chromium does not chemically interact with the polymer melt. Basing on these results, we propose a mechanism for deposit formation in plastic-processing machines and tools