Micron-Sized Nanoporous Vanadium Pentoxide Arrays for High-Performance Gel Zinc-Ion Batteries and Potassium Batteries

Abstract

High-performance cathodes are essential for all kinds of rechargeable batteries, and vanadium pentoxide (V2O5) has wide applications as a cathode in various batteries because of its high theoretical capacity, abundant reserves, and high safety performances. However, the irreversible phase transitions and sluggish ion diffusion limit its advancements. Herein, morphology-tunable micron-sized nanoporous V2O5 arrays are synthesized from V2CT x MXene by a one-step annealing process. The component and structure of the V2CT x MXene are simply controlled by regulating the reaction time. The effects of annealing conditions on crystallinity, microstructure, and electrochemical performance of V2O5 are further probed. The rationally designed V2O5 possesses special porous architecture, 2D structure, and pseudocapacitive effect, which ensures high ion accessibility, excellent structure stability, and fast charge transport. As a consequence, the optimal V2O5 cathode for gel zinc-ion batteries exhibits high capacity (358.7 mA h g–1 at 200 mA g–1 after 400 cycles), superior rate performance (250.4 mA h g–1 at 8000 mA g–1), and stable long-term cyclability (279 mA h g–1 at 2000 mA g–1 over 3500 cycles). The zinc storage enhancing mechanism is assessed by quantitative kinetics analysis. Furthermore, the V2O5 cathode also delivers an improved potassium storage performance. This work may provide a universal avenue to fabricate high-performance electrodes from MXene-based materials for next generation battery systems.

In‐Situ Electrochemically Activated Surface Vanadium Valence in V2C MXene to Achieve High Capacity and Superior Rate Performance for Zn‐Ion Batteries

“…Even at 10, 15, 20, 25, and 30 A g −1 , significantly high discharge capacities of 386, 378, 371, 365, and 358 mAh g −1 are achieved (Figure 3b,c). As expected, the rate capability of 1.8‐V 2 CT x is far better than many reported high‐performance cathodes such as V 2 O 5 , [ 28 ] V 2 O 5 ⋅nH 2 O, [ 34 ] V 2 O 5 @PEDOT/CC, [ 35 ] where PEDOT/CC is poly(3,4‐ethylenedioxythiophene)/carbon cloth, NaCa 0.6 V 6 O 16 ⋅3H 2 O, [ 22 ] Co(III)‐Co 3 O 4 , [ 36 ] δ‐MnO 2 , [ 37 ] and Na 0.33 V 2 O 5 ; [ 38 ] see Figure 3d for a detailed comparison. The superior high energy and power densities of 1.8‐V 2 CT x are clearly evident in the Ragone plot.…”

“…Notably, the discharge capacity of 1.8‐V 2 CT x is almost unaffected, with enhanced current densities that are rarely seen in most other reported cathodes for ZIBs. [ 22,28,34–39 ] From 1 to 5 A g −1 , the delivered capacity only slightly decreases to 398.1 mAh g −1 , with nearly 94% of the capacity maintained at 1 A g −1 . Even at 10, 15, 20, 25, and 30 A g −1 , significantly high discharge capacities of 386, 378, 371, 365, and 358 mAh g −1 are achieved (Figure 3b,c).…”

“…[ 26,27 ] Notably, the accordion‐like V 2 CT x , stacked from a large amount of V‐C‐V monolayers, exhibits numerous ordered nanochannels to facilitate charge transport, which can serve as a multi‐branch parallel circuit and consequently offer high power output. [ 17,28 ] Moreover, the accessible surfaces of 2D V 2 CT x are sufficient to provide adequate active sites for the intercalation/deintercalation of Zn 2+ ions. Nevertheless, there are few reports about utilizing V 2 CT x as cathode for ZIBs to date, since V 2 CT x exhibits unreasonably low discharge capacity.…”

Advanced Anode Materials of Potassium Ion Batteries: from Zero Dimension to Three Dimensions

“…First of all, the surface charge density of these multivalent metal ions is relatively high, resulting in greater mutual repulsion between cations and greater interaction between cations and host materials, which is not conducive to high capacity and high rate performance for batteries [ 22 ]. Besides, the potentials of Zn/Zn 2+ (− 0.76 V vs. SHE) [ 23 ], Mg/Mg 2+ (− 2.37 V vs. SHE) [ 14 ], Al/Al 3+ (− 1.76 V vs. SHE) [ 13 ] are much higher than that of Li/Li + (− 3.04 V vs. SHE), indicating that it is difficult for these batteries to obtain high operating voltages. There are many other problems that hinder their development.…”

A novel low-cost and environment-friendly cathode with large channels and high structure stability for potassium-ion storage

“…For KIB technologies, several families have been explored as anode materials with high capacity and long cyclability, including intercalation-type, conversion-type, and alloying type materials [8][9][10][11][12][13][14][15][16]. In comparison, the development of ideal cathode materials, such as Prussian blue analogues (PBAs), oxides, polyanions, and organics [17][18][19][20][21][22] are sluggish. For instance, despite of enormous investigations on PBAs, of which the three-dimensional (3D) open framework structure is promising for K-ion storage, the preparation of defect-free and water-free PBAs is difficult, which deteriorates the electrochemical performance of PBAs in terms of kinetics, Coulombic efficiency (CE), and cycling life [23][24][25][26].…”