Direct Recycling of All‐Solid‐State Batteries with a Halide Solid Electrolyte via Water‐Based Separation: Interactions of Electrode Materials in Aqueous Li 3 InCl 6 Solutions

Despite extensive research in the field of all‐solid‐state batteries, there has been limited attention to their recycling, which is crucial for achieving long‐term sustainability. Different electrolyte and electrode combinations must be considered for the recycling of these batteries, each requiring a detailed investigation of potential recycling approaches. The halide‐based solid electrolyte, Li 3 InCl 6 , has attracted significant attention due to its high‐room‐temperature lithium‐ion conductivity and its ability to recover its initial crystal structure after dissolution in water without significant electrochemical deterioration. This structural reversibility could potentially enable a direct recycling approach, allowing for the separation of the electrolyte from active electrode materials when dissolved in H 2 O. To assess the recycling compatibility, the interactions of Li 3 InCl 6 with different electrode materials (Li 4 Ti 5 O 12 , LiCoO 2 , LiMn 2 O 4 , carbon‐coated LiFePO 4 , LiNi 0.8 Mn 0.1 Co 0.1 O 2 , and LiNi 0.8 Co 0.15 Al 0.05 O 2 ) are studied during dissolution. Interactions arising from Lewis‐acid and Lewis‐base reactions can be identified using a combination of X‐ray diffraction, X‐ray photoelectron spectroscopy, and inductively coupled plasma mass spectrometry. Depending on the material combination, these interactions significantly impact the electrochemical properties of both recycled Li 3 InCl 6 and the electrode materials compared to the pristine samples.