Laser constructed bulk oxygen vacancy caused high P doping for boosting the sodium-storage capability

Defect-assisted heteroatom doping can effectively enhance the intrinsic transfer characteristics of carriers in the crystal structure, which advantages over fast and efficient charge storage. In this work, a three-dimensional self-supporting titanium dioxide nanoparticle rich in bulk vacancies (L-TiOx) on titanium substrate is synthesized by pulsed laser. Different from the surface vacancies, the bulk oxygen defects of L-TiOx cause a uniform and bulk phosphorus (P) doping with a high concentration of similar to 5.71 at %, which endows the elevated electronic conductivity, and accelerates the transport of Na+. The obtained P-doped L-TiOx (LP-TiOx) as an anode material in sodium-ion batteries (SIBs) provides a reversible capacity of 400 mAh g(-1) at 200 mA g(-1), outstanding rate capability of 196 mAh g(-1) at 10,000 mA g(-1), and maintains stable performance over 1000 cycles. In situ X-ray diffraction and ex situ high-resolution transmission electron microscopy show that LP-TiOx exhibits robust mechanical behavior with almost no lattice change under (de)sodiation. This work supplies a novel idea for high-concentration bulk heteroatoms doping to enhance the electrochemical performance of SIBs.