Synthesis and Electrochemical Performance of KVO/GO Composites as Anodes for Aqueous Rechargeable Lithium-Ion Batteries

Abstract

K 0.25 V 2 O 5 (KVO) and K 0.25 V 2 O 5 /graphene oxide (KVO/GO) have been successfully synthesized by a chemical coprecipitation method and a subsequent calcination process. The structure and morphology of KVO and KVO/GO were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The asobtained vanadate and vanadate modified by GO materials were used as anodes with LiMn 2 O 4 as a cathode and saturated LiNO 3 as an electrolyte to assemble an aqueous rechargeable lithium-ion battery (ARLB). The cyclic voltammogram curves of both KVO and KVO/GO electrodes exhibited three pairs of redox peaks corresponding to charge/discharge platforms. We found that a small amount of graphene oxide added improved the electrochemical performance more significantly than excess graphene oxide. The as-prepared KVO/GO//LiMn 2 O 4 could not only improve the initial discharge capacity but could also reduce the attenuation at a high current density. Furthermore, the ARLB with a KVO/GO anode exhibited an excellent rate performance and super long cycle life. These good electrochemical properties of this new ARLB system actually provided feasibility for application in large-scale power sources and energy storage devices.

Robust Hewettite HKV6O16·4H2O/CNT Nanosheets as High-Performance Cathodes for Sustainable Mg2+ Storage

“…During the electrochemical cycling processes, K + in HKV 6 O 16 can be exchanged with Mg 2+ ions. , The EDS spectrum in Figure b,c shows that after cycling, the content of K significantly decreases, while the content of Mg significantly increases. Based on this analysis, we infer that during the electrochemical processes, K + in HKV 6 O 16 is extracted from the material, and Mg 2+ is embedded in the structure …”

“…Based on this analysis, we infer that during the electrochemical processes, K + in HKV 6 O 16 is extracted from the material, and Mg 2+ is embedded in the structure. 28 Figure 6a shows the diffusion kinetics of Mg 2+ in the HKVO/CNT cathode via GITT curves. The D GITT can be calculated from the potential response of a low constant current pulse (20 mA g −1 ) on the basis of the following equation…”

Hydrothermal Synthesis of (NH4)2V7O16/Reduced Graphene Oxide Composite with Enhanced Storage Performance for Aqueous Lithium‐Ion Batteries

“…[ 12,14a,21 ] Finally, rGO can improve the electrical conductivity and effectively suppress vanadium dissolution of the electrode by acting as a physical barrier between the ammonium vanadium bronze and the aqueous solution. [ 13,16,22 ]…”

“…with an extended cycle life and a higher lithium-ion diffusion coefficient. [13] Hepta-vanadium bronze (NH 4 ) 2 V 7 O 16 is a relatively novel anode for aqueous rechargeable lithium-ion batteries. However, its inferior specific capacity and moderate rate capability restrict its practical application.…”

“…[ 12 ] The ALB utilizing a K 0.25 V 2 O 5 /GO anode showed exceptional rate performance with an extended cycle life and a higher lithium‐ion diffusion coefficient. [ 13 ]…”