The study focuses on the influence of Ni and Bi on alkaline ethanol oxidation reaction (EOR) activities, stabilities and structure characteristics of carbon supported Pd-based nanocatalysts (Pd/C, Pd 60 Ni 40 /C, Pd 60 Bi 40 /C, Pd 60 Ni 20 Bi 20 /C) by cyclic voltammetry/chronoamperometry using rotating disk electrode and various physico-chemical methods such as X-ray powder diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy coupled with energy dispersive X-ray spectroscopy and inductively coupled plasma optical emission spectrometry. Nickel generates more adsorbed OH on the Pd catalyst surface than Bi and promotes the oxidation of adsorbed ethanol species. This results in a low onset potential toward ethanol oxidation with high current density. The presence of Bi facilitates high tolerance toward various reaction intermediates resulting from the incomplete ethanol oxidation, but might also initiate the agglomeration of Pd nanoparticles. The novel Pd 60 Ni 20 Bi 20 /C nanocatalyst displays exceptional byproduct tolerance, but only satisfying catalytic activity toward ethanol oxidation in an alkaline medium. Therefore, the EOR performance of the novel carbon supported ternary Pd x Ni y Bi z anode catalyst with various atomic variations (Pd 70 Ni 25 Bi 5 /C, Pd 70 Ni 20 Bi 10 /C, Pd 80 Ni 10 Bi 10 /C and Pd 40 Ni 20 Bi 40 /C) using the common instant reduction synthesis method was further optimized for the alkaline direct ethanol fuel cell. The carbon supported Pd:Ni:Bi nanocatalyst with atomic ratio of 70:20:10 displays outstanding catalytic activity for the alkaline EOR compared to the other Pd x Ni y Bi z /C nanocatalysts as well as to the benchmarks Pd/C, Pd 60 Ni 40 /C and Pd 60 Bi 40 /C. The synergy and the optimal content in consideration of the oxide species of Pd, Ni and Bi are crucial for the EOR kinetic enhancement in alkaline medium.

The dissolution of transition metals (TMs) from cathode materials and their deposition on the anode represents a serious degradation process and, with that, a shortcoming of lithium-ion batteries. It occurs particularly at high charge voltages (>4.3 V), contributing to severe capacity loss and thus impeding the increase of cell voltage as a simple measure to increase energy density. We present here for the first time the online detection of dissolved TMs from a Ni-rich layered oxide cathode material with unprecedented potential and time resolution in potentiodynamic scans. To this aid, we used the coupling of an electroanalytical flow cell (EFC) with inductively coupled plasma mass spectrometry (ICP-MS), which is demonstrated to be an ideal tool for a fast performance assessment of new cathode materials from initial cycles. The simultaneous analysis of electrochemical and dissolution data allows hitherto hidden insights into the processes’ characteristics and underlying mechanisms.

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