Oxygen vacancies enhance the electrochemical performance of carbon-coated TiP2O7-y anode in aqueous lithium ion batteries

• Published in: Electrochimica acta Vol. 320; p. 134555
• Main Authors: Bin, Duan, Wen, Yunping, Yuan, Yingbo, Liu, Yao, Wang, Yonggang, Wang, Congxiao, Xia, Yongyao
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 10.10.2019; Elsevier BV
• Subjects: Anode; Anodes; Anodic coatings; Aqueous lithium ion batteries; Carbon; Carbon coating; Electrochemical analysis; Electrode materials; Electron microscopes; Energy storage; Lithium; Lithium manganese oxides; Lithium-ion batteries; Organic chemistry; Oxygen; Oxygen vacancies; Photoelectrons; Rechargeable batteries; Titanium; Titanium pyrophosphate; Vacancies; X ray photoelectron spectroscopy; Titanium pyrophosphate; Aqueous lithium ion batteries; Oxygen vacancies; Anode; Carbon coating
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2019.134555

In this paper, a titanium pyrophosphate (TiP2O7) anode with oxygen vacancies is prepared by a simple one-pot solid method, exhibiting great performance. Herein, we study on the physical and chemical changes of TiP2O7-y with oxygen defect, and compare it with pure TiP2O7 through scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and so on. It is found that the introduction of oxygen vacancies leads an improved electronic conductivity compared to the pure TiP2O7 sample. Intriguingly, the TiP2O7-y with oxygen defect displays an enhanced electrochemical performance in aqueous lithium ion batteries (ALIBs), with a larger capacity of TiP2O7-y (57 mAh g−1) as compared to pure TiP2O7 (17 mAh g−1) at 0.2 A g−1. After carbon-coating treatment, the C–TiP2O7-y anode demonstrates outstanding capacity and cycling performance with a capacity retention of 89% after 500 cycles at 0.5 A g−1. More importantly, the full ALIBs coupled with LiMn2O4 cathode maintains 85% capacity after 800 cycles at 0.1 A g−1. This study underscores the potential importance of incorporating oxygen vacancies into metal oxides as an alternative to modify the electrode materials in energy storage field. A highly performance TiP2O7 with oxygen vacancies anode exhibits the superior electrochemical performance in aqueous rechargeable lithium batteries. [Display omitted] •A highly performance TiP2O7 material with oxygen vacancies is designed by a simple one-pot solid method.•The anoxia TiP2O7-y displays an improved electronic conductivity and large discharge capacity.•These improvement can be attributed to the mixed Ti4+/Ti3+ valence state and well-dispersed carbon layer.