In this talk I will focus on applying in situ transmission electron microscopy (TEM) and lab-on-a-chip to mechanistic investigations of energy materials. Recent advances in nano-manipulation, environmental TEM and MEMS have allowed us to investigate coupled mechanical and electrochemical phenomena with unprecedented spatial and temporal resolutions. For example, we can now quantitatively characterize liquid-solid and gas-solid interfaces at nanometer resolution for in situ corrosion, fatigue and hydrogen embrittlement processes. These experiments greatly complement our modeling efforts, and together they help provide insights into how materials degrade in service due to combined electrochemical-mechanical forces.