Next generation solid-state lithium metal batteries: complex analysis of the positive and negative electrodes evolution upon cycling using soft and tender X-rays methods.

Li metal solid-state batteries are next generation batteries promising several key advantages over traditional Li-ion batteries, including enhanced safety, lower cost, higher energy density, and a long lifespan. Safe batteries is a pre-requisite for their massive deployment in the electric vehicles, however, various processes taking place at both positive and negative electrodes may jeopardize the battery lifespan. Additionally, these processes will be also affected by the battery operation, e.g. temperature, charge (C) and discharge (D) protocol (current density) etc. In this project, we want to focus and compare the state of the positive (LiNixMnyCozO2, NMC-based electrode) and negative (metallic Li) electrodes surfaces at different states of health (SOHs) for 3 states of charge (SOCs) cycled under three different charge/discharge regimes simulating real battery operation conditions: (i) D = 0.5h , C = 1h; (ii) D = 4h , C = 1h; (iii) D = 12h , C = 1h, where C will be fixed. Soft X-ray absorption (sXAS) at CIRCE/ALBA (or other facility) and hard X-ray photoelectron spectroscopies (HAXPES) at P22/DESY (via ReMade-TNA project) have been selected due to their surface sensitivity; ability to probe transition metals (TMs), oxygen and lithium; and complementary information on the electronic distribution provided by these two methods.