Rechargeable lithium-ion batteries (LIBs) are widely used in electrified vehicles, consumer electronics, and stationary energy storage systems. Simultaneous realization of high safety and high energy density/performance is a perpetual pursuit. Unfortunately, conventional batteries are passive devices where the performance, safety, and calendar/cycle life are all dictated by the electrochemical reactivity at ever-present anode/electrolyte and cathode/electrolyte interfaces. An inherent conflict between the reactivity and stability of battery materials persists at the electrode/electrolyte interfaces (EEIs). More specifically, highly reactive electrode/electrolyte materials provide high power and high performance but result in poor safety and accelerated degradation even when the battery is not in use. Highly stable (i.e., less reactive) electrode/electrolyte materials give rise to battery safety, low degradation, low self-discharge, and long life, but such materials offer low power and performance. As a result, materials development for batteries has always aimed at trade-offs of finding electrode and electrolyte materials that are not too reactive but also not too stable.