A characteristic feature of crystallographic shear structures is the (at least) three regions in their electrochemical profiles and corresponding structure evolution: (i) sloping region, (ii) plateau-like region, (iii) sloping region. Examination of the voltage vs. capacity curves and derivative (dQ/dV) plots (Figure ) of Nb18W8O69 reveals a relatively sloped voltage profile. This can be quantified by comparing the full-width half-maximum of the derivative peak for Nb18W8O69 at 250 mV (Figure ) vs. H-Nb2O5 at 40 mV (Figure of ref. ). As was previously observed for TiNb2O7 and Nb16W5O55, the transition metal cation disorder significantly broadens the electrochemical features relative to that of H-Nb2O5. The transition metal cation disorder appears to suppress the proclivity of lithium cation ordering that can lead to phase transitions between lowenergy ordered compositions, which can be detrimental for high-rate performance. Another feature that is evident in the dQ/dV plots is the asymmetry in lithium insertion vs. extraction (Figure ).