This book reviews the impact of water content in lithium-ion batteries (LIBs) as well as the reactivity of anodes, cathodes and electrolytes with water and processes that provide water-resistance to materials in LIBs. Water in LIBs which were constructed with anode, cathode and organic electrolyte containing lithium salts can degrade the cell performance and seriously damage the materials present. However, because a small amount of water in cells contributes to the formation of the solid electrolyte interphase, complete removal of water from cells lowers the battery performance and...