The low electronic conductivity of spinel-structured Li4Ti5O12 could be improved by introducing CuV2O6. Herein, several Li4Ti5O12/CuV2O6 composites with different CuV2O6 contents have been successfully prepared by a facile liquid-phase dispersion technique. The amount of CuV2O6 in composites is shown to affect the particle size and electrochemical performances of Li4Ti5O12. The Li4Ti5O12/CuV2O6 composite prepared with a 5 wt % CuV2O6 content (referred to as 5 wt % Li4Ti5O12/CuV2O6) exhibits the best electrochemical performances among all the Li4Ti5O12/CuV2O6 composites. The initial discharge/charge capacities of the 5 wt % Li4Ti5O12/CuV2O6 composite reach 241.1/199.8 mAh g–1 and retain at 136.8/135.7 mAh g–1 over 500 cycles at 30 mA g–1 between 1.0 and 3.0 V. In addition, initial discharge/charge capacities of the 5 wt % Li4Ti5O12/CuV2O6 composite amount to 129.8/90.5 mAh g–1 even at 1200 mA g–1 with maintained discharge/charge capacities of 71.1/71.1 mAh g–1 over 2500 cycles, which are superior to the pristine Li4Ti5O12 in all cases. The detailed electrode kinetic analysis reveals that the introduction of the CuV2O6 phase can enhance the lithium-ion transferring rate and cycling stability of Li4Ti5O12. The enhanced lithium-storage mechanism of the 5 wt % Li4Ti5O12/CuV2O6 composite is clarified by in situ X-ray diffraction (XRD) analysis. The acquired data confirms that in situ formation of small amounts of metallic Cu during discharge/charge processes highly enhance the electronic conductivity and decreases the charge–transfer resistance of Li4Ti5O12. In sum, the as-obtained 5 wt % Li4Ti5O12/CuV2O6 composite has potential for future construction of high-rate and long-lifespan anode materials for Li-ion batteries. The work also provides an innovative route to improve electrochemical performances of Li4Ti5O12.
Novel ε-Cu 0.95 V 2 O 5 hollow microspheres assembled by single-crystalline nanoribbons can be easily synthesized directly from a hydrothermal reaction between V(IV)O(acac) 2 and Cu(NO 3 ) 2 in a solution containing a proper amount of polymer polyvinyl pyrrolidone (PVP, K30). A possible growth mechanism has been proposed. Electrochemical measurements demonstrate that the as-prepared ε-Cu 0.95 V 2 O 5 superstructures display a reversible capacity of 304 mAh g −1 , and could sustain respectable rate capability. By reinvestigating the cooperative displacement/intercalation (CDI) mechanism of ε-Cu 0.95 V 2 O 5 using cyclic voltammetry (CV), ex situ XRD , and ex situ SEM–EDS techniques, it is found that the copper dissolution problem, which leads to poor capacity retention of cells operating on Li-driven Cu extrusion–insertion process, has not been well tackled due to its superstructure collapse. Rational electrode configuration design is urgently needed. In addition, single-crystalline α-CuV 2 O 6 nanograins are obtained by calcining the micro-nanostructured ε-Cu 0.95 V 2 O 5 precursor. The post-treated α-CuV 2 O 6 exhibits high discharge capacity of 507 mAh g −1 at 20 mA g −1 and 390 mAh g −1 at 80 mA g −1 , indicating it is a promising cathode candidate for long-term and high-rate lithium primary batteries .
Xu Li,Yifang Zhang,Qiao Xia,Jiye Fan,Huaxiang Lin,Rusheng Yuan,Jinlin Long
In this study, an Ag/CuV 2 O 6 composite was constructed by loading Ag NPs onto CuV 2 O 6 nanowires through a sodium borohydride reduction method. The introduction of Ag NPs significantly enhanced the photocatalytic antibacterial effect of CuV 2 O 6 . Specifically, the material exhibited the optimal photocatalytic antibacterial performance when the Ag loading was 3%. During the antibacterial process, as the illuminated time increases, the membrane structure of bacteria is gradually impaired, and intracellular contents including K + , RNA, and proteins are gradually leaked out, ultimately resulting in bacterial inactivation. EPR and free radical scavenging experiments have confirmed that reactive oxygen species (ROS), including singlet oxygen ( 1 O 2 ) and superoxide anion radicals (·O 2 - ), generated via photocatalysis, are the main factors in killing bacteria. As an excellent electron transporter, Ag effectively promotes the separation of electron-hole pairs in CuV 2 O 6 , enhances the generation efficiency of ROS, and thereby improves the photocatalytic antibacterial activity. To address the limitation of photocatalysis requiring continuous light irradiation, the long-afterglow fluorescent material ZnGa 2 O 4 :0.5%Tb 3+ was further introduced. Under intermittent light irradiation, the material stores energy upon excitation by the light source. After the light irradiation is terminated, it continues to activate the Ag/CuV 2 O 6 composite, allowing the generation of ROS even in the dark and thus achieving a delayed antibacterial effect. This study provides a new strategy to reduce the dependence of photocatalytic antibacterial technology on continuous light sources.
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