Youcai Ding,Yuqi Peng,Wenyong Chen,Yunjuan Niu,Shougang Wu,Xianxi Zhang,Linhua Hu
Rechargeable aqueous zinc-ion battery is a promising energy storage device because of its low cost and high safety. However, they are still in their infancy due to the limited choice of cathodes with high capacity and satisfactory cycling performance. In this work, porous V 2 O 5 materials were obtained by pyrolysis of vanadium-MOF and adopted as intercalation cathode for aqueous zinc-ion batteries . V 2 O 5 purchased commercially as a control, the effects of specific surface area, pore size distribution and mixed valence of electrodes on the performance of batteries were studied. The novel cathode delivers high capacities of 300 mA h g − 1 compared to 60 mAh g − 1 for C-V 2 O 5 at current density of 100 mA g − 1 . The energy density of this Zn ion battery is about 230 Wh kg − 1 , which is much higher than commercial lead acid batteries . The capacity of P-V 2 O 5 electrode retains 120 mA h g − 1 even at 2000 mA g − 1 , which is much higher than that of C-V 2 O 5 . Moreover, the structure of V 2 O 5 nanoplates and their composites with carbon materials can improve the cyclic stability.
Pan Zixin,Liang Xiaoping,Yan Su,Zeng Jing,Bai Jinshuo,Zhang Dequan,Yang Guixiang,Liu Zhifeng
Electrochromic glass, one of the green energy-saving building materials, get more and more attention. The advancement of efficient ion storage film become a hot topic of research. The porous V 2 O 5 ion-storage film was prepared by sol-gel method using polyethylene glycol (PEG) as the pore-former. The peak current of porous V 2 O 5 films heated at 300 °C increased substantially due to the volatility temperature of PEG at 285 °C. The mutual effects of the PEG content, heat treatment temperature, and heat treatment time on the structure and electrochromic properties of porous V 2 O 5 film were investigated by the response surface method (RSM). The results show that the influence extent on ion storage is: heat treatment temperature > PEG content > heat treatment time. Under optimized process parameters of PEG content 6.2 g/100 mL sol, heat treatment time 4 h, heat treatment temperature 310 °C, the porous V 2 O 5 film exhibited excellent ion storage capacity (87.28 mC·cm −2 ). The electrochromic device (ECD) with optimized porous V 2 O 5 ion-storage film as the counter electrode of electrochromic WO 3 film has been successfully assembled, which shows fascinating performance with high optical contrast (87.8% at 550 nm) and fast response time (bleaching/coloring: 4.5/3.7 s). Graphical Abstract
Rechargeable aqueous zinc-ion batteries (ZIBs) have received considerable attention for large-scale energy storage applications due to the unique merits of high energy density, eco-friendliness and reliable safety. However, the development of high performance cathodes is still hampered by their inferior reversibility and sluggish Zn 2+ diffusion kinetics, resulting in insufficient rate capability and poor cycling performances. Herein, we employed a feasible “two-in-one” strategy to intercalate conductive polymer (polyaniline, PANI) as pillar molecules into the V-MOF-derived hierarchical porous V 2 O 5 (designated as PVO) and used as cathode for high-performance ZIBs. The high specific surface area and nanobelt-like porous structure endowed PVO with abundant accessible electrochemical active sites and shortened the electrons/ions transfer pathways, further delivering a high discharge capacity (489 mAh g −1 at 0.1 A g −1 and 97.2% capacity retention after 100 cycles). Meanwhile, the intercalation of PANI not only effectively expanded the Zn 2+ diffusion channels, but also improved the structural stability during cycling as “interlayer pillars”. More importantly, the introduction of PANI could enhance the conductivity of the overall structure and weaken the electrostatic interaction between Zn 2+ and PVO host, thereby suppressing the collapse of the layered structure. Accordingly, the obtained PVO cathode exhibited excellent rate capability (375 mAh g −1 at 5.0 A g −1 ) and satisfactory cycling stability (91.8% capacity retention after 2000 cycles at 8.0 A g −1 ). Moreover, the reversible Zn 2+ storage mechanism was further investigated by kinetics analysis and DFT calculations. These ideal results provide key insights into the design of MOF-based cathode materials for high-performance aqueous zinc ion batteries.
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