Engineering Vanadium Pentoxide Cathode for the Zero‐Strain Cation Storage via a Scalable Intercalation‐Polymerization Approach

Abstract

The layered V 2 O 5 cathode exhibits appealing features of multiple electron redox processes and versatile cation-storage capacities. However, the huge volume respiration induces structural collapse and limits its commercial-scale deployment. Herein, a scalable water-bath strategy is developed to tailor the (001) spacing of the bulk V 2 O 5 from the original 4.37 Å to its triple value (14.2 Å). The intercalated polyaniline (PANI) molecules act as pillars in the V 2 O 5 interlayer, thus affording the abundant storage sites and enhanced cation diffusivities of Li + , Na + , or hydrated Zn 2+ . Upon various cations (de-)intercalation, transmission-mode operando X-ray diffraction is employed to document the zero-strain behavior of the PANI-intercalated V 2 O 5 . This scalable intercalationpolymerization strategy, coupled with the compatibility study of the ionic radius and the c-lattice for the layered structure, enables the rational engineering of the intercalation-type cathodes toward facile reaction kinetics.

Rapid Electrochemical Activation of V2O3@C Cathode for High‐Performance Zinc‐Ion Batteries in Water‐in‐Salt Electrolyte

“…There is no obvious oxidative decomposition of water in both Zn(CF 3 SO 3 ) 2 and water‐in‐salt electrolytes. Moreover, the positions of the second pair of redox peaks are about 0.90 V and 1.01 V in both Zn(CF 3 SO 3 ) 2 and Zn(CF 3 SO 3 ) 2 +LiTFSI water‐in‐salt electrolytes, and the position is exactly the same with V 2 O 5 , as reported previously [14,18] . However, the integral area of the redox peaks in the Zn(CF 3 SO 3 ) 2 +LiTFSI water‐in‐electrolyte is larger than that in the Zn(CF 3 SO 3 ) 2 solution, especially the area of the second peak that are originated from V 4+ →V 5+ , indicating more sufficient oxidation/reduction reactions take place in the water‐in‐salt electrolyte.…”

“…Moreover, the positions of the second pair of redox peaks are about 0.90 V and 1.01 V in both Zn(CF 3 SO 3 ) 2 and Zn(CF 3 SO 3 ) 2 + LiTFSI water-in-salt electrolytes, and the position is exactly the same with V 2 O 5 , as reported previously. [14,18] However, the integral area of the redox peaks in the Zn(CF 3 SO 3 ) 2 + LiTFSI water-in-electrolyte is larger than that in the Zn(CF 3 SO 3 ) 2 solution, especially the area of the second peak that are originated from V 4 + !V 5 + , indicating more sufficient oxidation/reduction reactions take place in the waterin-salt electrolyte. It's worth noting that the first redox peaks shift to a high voltage in the water-in-salt electrolyte than Zn(CF 3 SO 3 ) 2 electrolyte, that it is mainly due to the merger of V 3 + !V 4 + with parts of the V 4 + !V 5 + redox peaks.…”

“…Generally, the interlayer space can be substituted with water molecules, [14] cations, anions, [15,16] or organic molecules (such as conductive polymers). [17,18] Pioneering research by Nazar and co-workers demonstrated that metal ions and H 2 O molecules in the layered Zn 0.25 V 2 O 5 • nH 2 O can act as pillars, thus improving the structural stability during cycling and mobilizing cation migration. [8] H 2 O molecules can function like a "lubricant" to effectively facilitate fast Zn 2 + transportation.…”

“…Currently, the most effective solution is to expand the interlayer distance to stabilize the structure of V 2 O 5 through a guest pre‐intercalation strategy. Generally, the interlayer space can be substituted with water molecules, [14] cations, anions, [15,16] or organic molecules (such as conductive polymers) [17,18] . Pioneering research by Nazar and co‐workers demonstrated that metal ions and H 2 O molecules in the layered Zn 0.25 V 2 O 5 ⋅ n H 2 O can act as pillars, thus improving the structural stability during cycling and mobilizing cation migration [8] .…”

Mechanistic Insight into Polypyrrole Coating on V2O5 Cathode for Aqueous Zinc‐Ion Battery

“…[18] However, the dissolution problem of V 2 O 5 in aqueous solution leads to unstable cycle performance. [19] To address this issue, some technical strategies have been explored for V 2 O 5 in the recent years, for example, conformal polymer shell coating of poly(3, 4-ethylenedioxythiophene), [20] H 2 O and NH 4 + ions intercalation, [21] integration with conductive polymer [22,23] and use of a new-type "water-in-salt" electrolyte. [24] Among these improved approaches, construction a composite cathode of V 2 O 5 /conductive polymer is a promising way to improve the performance of zinc-ion battery.…”