Hydrogen tetratitanates (H2Ti4O9, HTO) are synthesized and studied as anode materials for sodium-ion batteries. Using n-propylamine molecular pillars, the interlayer spacing of HTO is increased from 0.86 to 1.58 nm. The electrochemical Na+ intercalation properties of pristine and interlayer-expanded HTOs are studied with detailed electrochemical characterization and operando electrochemical dilatometry experiments. Interlayer-expansion results in higher maximum sodiation capacity and improved kinetics and electrochemical reversibility.