Effect of V-doping on structure and electrical conductivity of Magnéli phase Ti4O7

Magnéli phase Ti4O7 has been widely used in a range of electrochemistry disciplines due to its stable structure and excellent electrical conductivity. However, the conductivity advantages of Ti4O7 as a conductive addition are not readily visible, and the conductivity of Ti4O7 is significantly decreased by the presence of other titanium suboxide. The conductivity qualities of Ti4O7 can be improved by V. Studies on the impact of the amount of V on the structure and conductivity of Ti4O7, as well as the mechanism of V-enhanced conductivity of Ti4O7, are scarcely discernible. As a result, the effects of different V doping levels on the structure and conductivity of Ti4O7 were examined in this study, and when paired with carrier mobility calculation based on density functional theory (DFT) calculations, the mechanism behind V-enhanced Ti4O7 conductivity was discovered. Simple solvothermal and hydrogen reduction methods were used to prepare V-doped Ti4O7 at a variety of doping concentration. The conductivity of Ti4O7 improved with increasing V doping, however the presence of second phase (Ti1−xVx)2O3 decreased the conductivity of Ti4O7. This work is important for further understanding the optimal doping amount for V-enhanced Ti4O7 conductivity and the V-enhanced Ti4O7 conductivity behavior. •The conductivity of Ti4O7 increases with the increase in the solid solution of V.•The presence of the second phase (Ti1−xVx)2O3 deteriorates the conductivity of (Ti,V)4O7.•The maximum solid solubility of V in Ti4O7 is less than 18.01 at%.•The synergistic effect between carrier mobility and carrier concentration leads to V-enhanced conductivity of Ti4O7.