Fast charging and high volumetric capacity are two of the critical demands for sodium-ion batteries(SIBs).Although nanostructured materials achieve outstanding rate performance,they suffer from low tap density and small volumetric capacity.Therefore,how to realize large volumetric capacity and high tap density simultaneously is very challenging.Here,N/F co-doped TiO2/carbon microspheres(NF-TiO2/C)are synthesized to achieve both of them.Theoretical calculations reveal that N and F co-doping increases the contents of oxygen vacancies and narrows the bandgaps of TiO2 and C,improving the electronic con-ductivity of NF-TiO2/C.Furthermore,NF-TiO2/C exhibits the high binding energy and low diffusion energy barrier of Na+,significantly facilitating Na+storage and Na+diffusion.Therefore,NF-TiO2/C offers a high tap density(1.51 g cm-3),an outstanding rate performance(～125.9 mAh g-1 at 100 C),a large volumetric capacity(～190 mAh cm-3 at 100 C),a high areal capacity(～4.8 mAh cm-2)and an ultra-long cycling per-formance(～80.2％after 10,000 cycles at 10 C)simultaneously.In addition,NF-TiO2/C||Na3V2(PO4)3 full cells achieve an ultrahigh power density of 25.2 kW kg-1.These results indicate the great promise of NF-TiO2/C as a high-volumetric-capacity and high-power-density anode material of SIBs.

Key Laboratory of Colloid and Interface Chemistry,Ministry of Education,School of Chemistry and Chemical Engineering,Shandong University,Jinan 250100,Shandong,China;Institute for Superconducting and Electronic Materials,Australian Institute for Innovative Materials,University of Wollongong,Innovation Campus,North Wollongong,New South Wales 2500,Australia;Key Laboratory for Green Chemical Technology of Ministry of Education,R&D Center for Petrochemical Technology,Tianjin University,Tianjin 300072,China;Hefei National Laboratory for Physical Science at Microscale,Department of Chemistry,University of Science and Technology of China,Hefei 230026,Anhui,China

[1]Dan Lv;Dongdong Wang;Nana Wang;Hongxia Liu;Shaojie Zhang;Yansong Zhu;Kepeng Song;Jian Yang;Yitai Qian-.Nitrogen and fluorine co-doped TiO2/carbon microspheres for advanced anodes in sodium-ion batteries:High volumetric capacity,superior power density and large areal capacity)[J].能源化学,2022(05):104-112

Na+diffusion

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