Metal-Ceramic interfaces or Ceramic-Ceramic interfaces, such as those that are found in solid-state batteries or solid oxide fuel cells often possess unique attributes that contribute to properties and charge transfer kinetics that are often detrimental and sometimes favorable for performance. In this project, a multi-phase field theoretical framework is developed to predict the effects of interfacial space charge, composition, and mechanical integrity as a stepping stone to engineer advanced materials and devices for energy applications. For this project, a phase field theoretical framework is developed to predict the microstructure evolution of a multicomponent metallurgical junctions to identify processing parameters and geometrical features to improve joint integrity and device performance.