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We report on interphase modification by in situ generated protons (H+) via electropolymerization. The protons are released from oxidative electropolymerization of indole-3-carboxylic acid (InAc) us...

The ever-increasing demand for electrical energy storage technologies triggered by the demands for consumer electronics, stationary energy storage systems and especially the rapidly growing market of electro mobility boosts the need for cost-effective, highly efficient and highly performant rechargeable battery systems. After the successful implementation of lithium ion batteries (LIBs) in consumer electronics and electric vehicles, there is still a need for further improvements in terms of energy and power densities, safety, cost and lifetime. In the last decades, a large battery research community has evolved, developing all kinds of new battery materials, e.g., positive and negative electrode active materials for different cell chemistries, electrolytes, related auxiliary (inactive) materials and their constituents. Different battery cell setups, including so-called “half-cell”, “symmetrical-cell” and “full-cell” setups as well as two-electrode or three-electrode configurations, are described in the literature to be used in the laboratory for the electrochemical characterization of battery components like electrode materials and electrolytes. Typically, all cell setups display certain limitations or issues concerning their application for the parameter determination of battery materials. In this review article, we highlight the advantages but also the limitations of different cell setups, with special focus on two- and three-electrode configurations with or without the help of “auxiliary” excess capacity Li metal electrodes. We point out possible mistakes and/or misinterpretations and give the reader recommendations, i.e., a guide for the right choice of the cell setup/configuration appropriate for the intended aim of the electrochemical investigation.

In this work, carbon nanospheres (CS) are prepared by hydrothermal synthesis using glucose as precursor, followed by a subsequent carbonization step. By variation of the synthesis parameters, CS pa...

Pre-lithiation of anode materials can be an effective method to compensate active lithium loss which mainly occurs in the first few cycles of a lithium ion battery (LIB), due to electrolyte decomposition and solid electrolyte interphase (SEI) formation at the surface of the anode. There are many different pre-lithiation methods, whereas pre-lithiation using metallic lithium constitutes the most convenient and widely utilized lab procedure in literature. In this work, for the first time, solid state nuclear magnetic resonance spectroscopy (NMR) is applied to monitor the reaction kinetics of the pre-lithiation process of graphite with lithium. Based on static 7Li NMR, we can directly observe both the dissolution of lithium metal and parallel formation of LiCx species in the obtained NMR spectra with time. It is also shown that the degree of pre-lithiation as well as distribution of lithium metal on the electrode surface have a strong impact on the reaction kinetics of the pre-lithiation process and on the remaining amount of lithium metal. Overall, our findings are highly important for further optimization of pre-lithiation methods for LIB anode materials, both in terms of optimized pre-lithiation time and appropriate amounts of lithium metal.

In order to meet the sophisticated demands for large-scale applications such as electro-mobility, next generation energy storage technologies require advanced electrode active materials with enhanced gravimetric and volumetric capacities to achieve increased gravimetric energy and volumetric energy densities. However, most of these materials suffer from high 1st cycle active lithium losses, e.g., caused by solid electrolyte interphase (SEI) formation, which in turn hinder their broad commercial use so far. In general, the loss of active lithium permanently decreases the available energy by the consumption of lithium from the positive electrode material. Pre-lithiation is considered as a highly appealing technique to compensate for active lithium losses and, therefore, to increase the practical energy density. Various pre-lithiation techniques have been evaluated so far, including electrochemical and chemical pre-lithiation, pre-lithiation with the help of additives or the pre-lithiation by direct contact to lithium metal. In this review article, we will give a comprehensive overview about the various concepts for pre lithiation and controversially discuss their advantages and challenges. Furthermore, we will critically discuss possible effects on the cell performance and stability and assess the techniques with regard to their possible commercial exploration.