However, the capacity retention of cross-linked HTO-HDA at high rates is still slightly higher compared to pristine HTO, indicating the general favorability of increased interlayer spacing for charge storage kinetics. This is also in line with previous reports of our group on alkyldiamine-pillared vanadium oxide host materials. The cycling stability of HTO-based materials is tested by GCD at an intermediate rate of 500 mA g -1 (Fig. ). The performance degradation is most severe for pristine HTO, with a retention of 36 % of its initial capacity, while HTO-PA and HTO-HDA both retain about 55 % of their initial capacity after 1,000 cycles. The strong performance degradation for HTOs in organic lithium ion-based systems has been observed before and attributed to hydrogen gas evolution at strongly reductive potentials. This adverse effect on the cycling stability appears to be weakened in HTO-PA and HTO-HDA. We hypothesize that this is due to a stabilization of confined structural protons due to NH 3+ formation after introduction of amine groups. TEM images were recorded after cycling the show no visible signs of exfoliation or structural degradation (Fig. ). Favorable kinetics for ion intercalation in HTO host materials has been ascribed to ion-solvent cointercalation phenomena before, when specially formulated electrolytes were used. We hypothesize that a nanoconfinement-induced cointercalation mechanism is the origin of superior electrochemical kinetics of HTO-PA compared to HTO, which is known to exhibit solid-solution intercalation of desolvated Li + . Cointercalation reactions exhibit a reduced charge transfer resistance compared to the corresponding desolvated ion intercalation process, because of the circumvention of the desolvation step. Hence, we can probe this behavior using electrochemical impedance spectroscopy (EIS) at various states of charge To further support the hypothesis of a nanoconfinement-induced cointercalation mechanism in HTO-PA, the lithiation-induced structural changes occurring in the different host materials are analyzed during electrochemical cycling using operando XRD. The electrode materials are cycled by GCD at 50 mA g -1 in a modified coin cell setup with Kapton-sealed windows, while Xray diffractograms are continuously recorded in Debye-Scherrer geometry (transmission) with a focus on the signal representative of the interlayer spacing, i.e., the (200) set of planes. For pristine HTO, a continuous shift towards smaller interlayer spacing is observed during electrochemical lithiation (Fig. ), indicating a contraction of titanate layers upon insertion of a positive charge in the interlayer space. In the fully lithiated state, the HTO interlayer spacing contracted from ca. 0.8 to 0.74 nm. The interlayer spacing reversibly expands to its initial value after full electrochemical delithiation, suggesting a solid-solution intercalation mechanism of Li + . The behavior is fully reversible and is in line with previous observations of interlayer contraction of titanates upon both proton or lithium insertion. For HTO-PA, the operando XRD profiles show a different behavior (Fig. ). For interlayerexpanded HTO-PA, upon lithiation, the interlayer spacing further increases from 1.54 nm to ca. 1.68 nm. Upon delithiation, a further expansion to ca. 1.73 nm is observed. Similar observations are made for HTO-HDA (Fig. ). Furthermore, in the second lithiation cycle, the signal corresponding to the (200) plane loses intensity for HTO-PA, which indicates a loss of long-range crystalline order. The observations support the insertion of a large intercalant in HTO-PA (e.g., a partially solvated Li + ), which apparently leads to stronger structural changes of the host lattice compared to pristine HTO. The results are fully in line with the transition from solid-solution intercalation of desolvated Li + in HTO to ion-solvent cointercalation in HTO-PA and HTO-HDA. The intercalation of large ion-solvent complexes qualitatively explains the observed further expansion of the interlayer spacing. Furthermore, this electrochemicallyinduced expansion is likely facilitated by the non-cross-linked structure of HTO-PA, explaining its superior kinetics compared to HTO-HDA.