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<p>This supplementary material is a part of the presentation handout, pages 209–242, for the 51st Electrochemistry Workshop entitled “Fundamentals and New Approaches to Electrochemistry” organized by Kansai Branch of the Electrochemical Society of Japan on November 14–18, 2022 to be distributed at the workshop. / In situ/<em>operando</em> techniques for electrochemical systems are useful for understanding the electrochemical reactions, as we presented in Part 1. Here we present a series of in situ/<em>operando</em> techniques for battery applications. Now the in situ/<em>operando</em> techniques presented in this paper has become powerful tools for the development of advanced battery systems such as Li-ion batteries, solid-state batteries, and other beyond Li-ion batteries. In the present paper we introduce the in situ/<em>operando</em> cell design of each measurement technique and discuss how we apply each technique for in the advanced battery materials development.</p>