The cathodic redox potential is shifted negatively by ca. 200 mV in pillared HTOs, indicating a modified electrode reaction. Moreover, the charge storage kinetics are most favorable when employing non-cross-linking PA pillars compared to cross-linking HDA pillars or pristine HTO structure, yielding a reduced charge transfer resistance and increased reversibility. Employing electrochemical operando XRD, dilatometry and EQCM, we discovered that this is due to a nanoconfinement-induced transition in intercalation mechanism from solid-solution intercalation of desolvated Li + in pristine HTO to cointercalation of partially solvated Li + in pillared HTO.