Rechargeable batteries are promising energy storage technologies that provide high energy and power for applications such as electric vehicles, power grids that integrate intermittent renewable energy resources or AI data centers. Recent studies have shown enhanced electrochemical charge storage in electrodes that contain intentional structural defects (e.g., vacancies and interstitials) or with tailored interface/interphase. In this seminar, I will discuss recent works at the Electrochemical Energy Materials Laboratory at Boise State including engineering defects in electrode materials through ion irradiation, and operando electrochemical cycling, doping, as well as interface/interphase engineering in composite electrodes for metal ion batteries (e.g., Li ion and Na ion batteries). We hope to provide some perspectives regarding new pathways to design and engineering defects and interfaces in electrode materials with enhanced energy/power for sustainable energy storage systems.