DFT‐based ab initio Pourbaix diagrams represent a powerful tool to resolve the stable surface structure of an electrocatalyst under different environmental parameters such as the applied electrode potential and pH. Herein, a general approach for anode and cathode materials in lithium‐ion batteries (LIBs) is presented that enables to transfer the concept of surface Pourbaix diagrams from electrocatalysis to electrode materials employed in LIBs. This novel approach is exemplified at the example of the (111) facet for a single‐crystalline spinel lithium titanate (LTO) model electrode by combining constrained thermodynamics and density functional theory calculations. From electrocatalysis to battery science: Surface Pourbaix diagrams that rely on a constrained ab initio thermodynamics approach provide deep insights into the thermodynamically stable surface of an electrocatalyst at different environmental parameters such as the applied electrode potential and pH. This concept is transferred from electrocatalysis to electrode materials in lithium‐ion batteries and exemplified with a single‐crystalline spinel lithium titanate (111) model electrode.