ConFlat cell for operando electrochemical X-ray studies of lithium-ion battery materials in commercially relevant conditions

In situ and operando techniques play an important role in modern battery materials research and development. As materials characterization and application requirements advance, so too must the in situ/operando test methods and hardware. The effects of temperature, internal mechanical pressure and parasitic reactions due to, for example, cell sealing are critical for commercial scale-up but often overlooked in in situ/operando cell designs. An improved electrochemical operando cell for X-ray diffraction and spectroscopy using ConFlat-style flanges in combination with a beryllium window is presented. The cell is reusable and simple to fabricate and assemble, providing superior sealing, relevant and adjustable cell stack pressure, and reproducible charge/discharge cycling performance for short- and long-term experiments. Cell construction, electrochemical performance, and representative operando X-ray powder diffraction measurements with carbon and aluminium electrodes at temperatures between 303 and 393 K are provided. Operando electrochemical cell testing at high temperatures allows access to temperature-sensitive phase transitions and opens the way for analysis and development of new lithium-based cathode, anode and electrolyte materials for lithium-ion batteries.