Berlin 2018 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 15: Battery Materials
MM 15.2: Talk
Monday, March 12, 2018, 17:45–18:00, H 0106
Neutrons confirm longer lifetime for Li-ion cells with a befitting anode — •Neelima Paul1, Johannes Wandt2, Stefan Seidlmayer1, Sebastian Schebesta3, Martin J. Mühlbauer1,4,5, Oleksandr Dolotko1, Hubert A. Gasteiger2, and Ralph Gilles1 — 1Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, 85747 Garching — 2Chair of Technical Electrochemistry, Technische Universität München, 85748 Garching — 3VW-VM Forschungsgesellschaft mbH & Co. KG, 73479 Ellwangen — 4Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen — 5Helmholtz-Institute Ulm for Electrochemical Energy Storage, P.O. Box, 76021 Karlsruhe
Long battery life is important for stationary storage systems which typically use cells consisting of LFP cathode and a graphite anode similar to needle coke (NC) anode. Such LFP/NC cells typically lose 23% of relative capacity after 4750 cycles and 11% under storage. We report that changing the anode material from NC with a flaky morphology, to a mesocarbon microbeads (MCMB) anode with a spherical morphology can drastically increase the longitivity of batteries. In situ neutron diffraction shows that LFP/MCMB cells lose only 8 % of relative capacity under similar cycling conditions and suffer no capacity loss on storage. It also proves that the entire capacity loss is dominated by the loss of cyclable lithium; no other aging mechanisms like structural degradation or deactivation of anode or cathode materials are observed, highlighting the excellent structural stability and superior quality of the investigated cells.