Sodium-ion batteries (NIBs) are a promising alternative to complement lithium-ion batteries because of their reduced reliance on critical raw materials. While hard carbons are the most widely adopted anode material in NIBs, they suffer from a particularly low sodiation potential plateau with the risk of sodium plating when fastcharging, as well as a low initial Coulombic efficiency (ICE). Moreover, the (de)sodiation mechanism in hard carbons is still under debate, being complicated by their highly disordered structure. Alternatives to hard carbon as anode materials in NIBs are therefore needed, and layered titanates are promising candidates based on higher sodiation potential and structural/chemical variability. The composition and structure of titanates is highly versatile, particularly regarding the chemistry of their nanoconfined interlayer space that can be tailored by ion exchange reactions to contain alkali cations, protons, and/or water. Hydrogen titanates (HTOs) possess various amounts of nanoconfined structural protons and/or water within their interlayer space, and they have been demonstrated to be promising anode materials for electrochemical H + , Li + , Na + , and K + intercalation. The associated intercalation mechanisms and performance metrics can be strongly influenced by the interlayer properties of the host materials.