DFT-Guided Design of Dual Dopants in Anatase TiO for Boosted Sodium Storage.

Anatase titanium dioxide (TiO) has drawn great attention as an anode material in sodium ion batteries (SIBs), but it suffers from the sluggish diffusion kinetics of Na within TiO and inferior electronic conductivity. Herein, under the guidance of density functional theory (DFT), we propose a nitrogen and selenium dual-doped TiO system as an advanced SIB anode. Both DFT and experimental investigations reveal the cooperative effect of dopants in boosting the electrochemical performance of TiO, finding the optimal content ratio (N/Se at 1:3) for overall improved SIB performances. As expected, experimental results exhibit excellent sodium storage behavior of the N,Se-doped TiO, including high discharge capacity (142 mAh g at 2 A g), good rate performance (82 mAh g at 20 A g), and ultralong cyclability (97% retention over 5000 cycles at 2 A g). Our study underscores the importance of dual-heteroatom doping in the rational design of advanced electrode materials.