2019, Krause, A., Tkacheva, O., Omar, A., Langklotz, U., Giebeler, L., Dörfler, S., Fauth, F., Mikolajick, T., Weber, W.M.

Rapid decay of silicon anodes during lithiation poses a significant challenge in application of silicon as an anode material in lithium ion batteries. In situ Raman spectroscopy is a powerful method to study the relationship between structural and electrochemical data during electrode cycling and to allow the observation of amorphous as well as liquid and transient species in a battery cell. Herein, we present in situ Raman spectroscopy on high capacity electrode using uncoated and carbon-coated silicon nanowires during first lithiation and delithiation cycle in an optimized lithium ion battery setup and complement the results with operando X-ray reflection diffraction measurements. During lithiation, we were able to detect a new Raman signal at 1859 cm−1 especially on uncoated silicon nanowires. The detailed in situ Raman measurement of the first lithiation/delithiation cycle allowed to differentiate between morphology changes of the electrode as well as interphase formation from electrolyte components.

2019, Coll, M., Fontcuberta, J., Althammer, M., Bibes, M., Boschker, H., Calleja, A., Cheng, G., Cuoco, M., Dittmann, R., Dkhil, B., El Baggari, I., Fanciulli, M., Fina, I., Fortunato, E., Frontera, C., Fujita, S., Garcia, V., Goennenwein, S.T.B., Granqvist, C.-G., Grollier, J., Gross, R., Hagfeldt, A., Herranz, G., Hono, K., Houwman, E., Huijben, M., Kalaboukhov, A., Keeble, D.J., Koster, G., Kourkoutis, L.F., Levy, J., Lira-Cantu, M., MacManus-Driscoll, J.L., Mannhart, J., Martins, R., Menzel, S., Mikolajick, T., Napari, M., Nguyen, M.D., Niklasson, G., Paillard, C., Panigrahi, S., Rijnders, G., Sánchez, F., Sanchis, P., Sanna, S., Schlom, D.G., Schroeder, U., Shen, K.M., Siemon, A., Spreitzer, M., Sukegawa, H., Tamayo, R., van den Brink, J., Pryds, N., Granozio, F.M.

[No abstract available]

2013, Shuai, Y., Ou, X., Luo, W., Mücklich, A., Bürger, D., Zhou, S., Wu, C., Chen, Y., Zhang, W., Helm, M., Mikolajick, T., Schmidt, O.G., Schmidt, H.

This work reports the effect of Ti diffusion on the bipolar resistive switching in Au/BiFeO 3/Pt/Ti capacitor-like structures. Polycrystalline BiFeO 3 thin films are deposited by pulsed laser deposition at different temperatures on Pt/Ti/SiO 2/Si substrates. From the energy filtered transmission electron microscopy and Rutherford backscattering spectrometry it is observed that Ti diffusion occurs if the deposition temperature is above 600 C. The current-voltage (I-V) curves indicate that resistive switching can only be achieved in Au/BiFeO 3/Pt/Ti capacitor-like structures where this Ti diffusion occurs. The effect of Ti diffusion is confirmed by the BiFeO 3 thin films deposited on Pt/sapphire and Pt/Ti/sapphire substrates. The resistive switching needs no electroforming process, and is incorporated with rectifying properties which is potentially useful to suppress the sneak current in a crossbar architecture. Those specific features open a promising alternative concept for nonvolatile memory devices as well as for other memristive devices like synapses in neuromorphic circuits.