Lithium ion batteries are ubiquitous in our everyday lives and have revolutionized portable electronics and the transportation industry. As self contained energy storage systems, lithium ion batteries often appear as black boxes. However, the chemistry inherent to their function is diverse and complicated. Examples of mechanistic insight gained from in situ and operando characterization of lithium ion batteries will be highlighted in this presentation. This will include approaches to spatially locate and resolve productive and parasitic processes in functional energy storage materials and systems, with an emphasis on electrochemistry-based and electrochemistry-coupled approaches.