In-Situ Neutron Studies of Electrodes for Li-Ion Batteries Using a Deuterated Electrolyte: LiCoO2 as a Case Study

An electrochemical cell for in-situ neutron powder diffraction studies of electrode materials for lithium-ion batteries is presented. The device has a coin cell geometry, consisting of 8.4 cm diameter, circular components that can be stacked together and clamped tight using sixteen polyetheretherketone (PEEK) screws. The background issue associated with incoherent scattering from hydrogen within the organic electrolyte was addressed by replacing the normal electrolyte with a deuterated analogue, significantly improving the peak-to-background ratio of the in-situ neutron data. Initial in-situ studies showed clear structural evolution within LixCoO2 during charge in a half-cell with lithium metal as the counter electrode, in agreement with previous studies. In addition, the in-situ cell was shown to provide electrochemical performance comparable to that of equivalent coin cells of the commercial design and, following these demonstration studies, is available for in-situ structural studies of other lithium cathode and anode materials during charge/discharge cycling. (C) 2018 The Electrochemical Society.