Abstract
Unraveling Reversible By-Product Formation in Nanoflower-like Zn-Preintercalated V2CTx-Derived Bilayered Vanadium Oxide Cathodes for Aqueous Zn-Ion Batteries: In Situ and Ex Situ Insights in Performance-Determining Electrolytes
Meeting abstracts (Electrochemical Society), v MA2025-02(6), 871
24 Nov 2025
Abstract
Layered hydrated vanadium oxides have emerged as promising cathode materials for aqueous zinc-ion batteries (AZIBs), frequently delivering record-high specific capacities. However, their electrochemical cycling stability remains variable and highly sensitive to structural features, chemical composition, morphology, and electrolyte environment. One contributing factor to capacity fading is the formation of by-products, other than Zn-intercalated vanadium oxides, that are often irreversible or only partially reversible during cycling. A deeper understanding of how electrolyte composition influences by-product formation is essential for advancing AZIB technology.In this work, we synthesized, for the first time, a Zn-preintercalated V₂CTₓ MXene-derived bilayered vanadium oxide (MD-ZVO) with a nanoflower-like morphology and investigated its performance as a cathode in AZIBs using four different electrolytes: 2 M ZnSO₄, 2 M ZnCl₂, 30 m ZnCl₂, and 2.6 M Zn(OTf)₂ (OTf = CF₃SO₃). Among these, the cells employing 30 m ZnCl₂ and 2.6 M Zn(OTf)₂ demonstrated significantly improved cycling stability. This enhancement is attributed to the nanoflower morphology of MD-ZVO particles and the reduced material dissolution in saturated electrolytes. In situ and ex situ XRD analyses revealed the highly reversible formation of ZnxOTfy(OH)₂ₓ-y·nH₂O in 2.6 M Zn(OTf)₂ and Zn₅(OH)₈Cl₂·H₂O in 30 m ZnCl₂ electrolytes. Ex situ SEM imaging further confirmed the dynamic surface evolution of the MD-ZVO electrodes, showing that a dense by-product layer forms at the end of discharge and dissolves almost completely upon charging. This reversible by-product formation and decomposition process persisted consistently over 100 charge–discharge cycles, underscoring the robust structural adaptability of the cathode. These findings, combined with the high electrochemical stability observed in saturated electrolytes, suggest that reversible conversion-type reactions, alongside Zn²⁺/H⁺ intercalation, are central to the sustained capacity and long-term performance of MD-ZVO cathodes. We will discuss the underlying mechanisms governing MD-ZVO operation in AZIBs, as well as key material and electrolyte factors that contribute to its extended electrochemical stability under both low and high current densities.This work offers new insights into electrolyte-governed surface chemistry and points toward a broader design strategy for high-performance aqueous batteries through controlled structural evolution and reversible interfacial processes.
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Details
- Title
- Unraveling Reversible By-Product Formation in Nanoflower-like Zn-Preintercalated V2CTx-Derived Bilayered Vanadium Oxide Cathodes for Aqueous Zn-Ion Batteries: In Situ and Ex Situ Insights in Performance-Determining Electrolytes
- Creators
- Timofey Averianov - Drexel UniversityEkaterina Pomerantseva - Drexel University
- Publication Details
- Meeting abstracts (Electrochemical Society), v MA2025-02(6), 871
- Publisher
- The Electrochemical Society, Inc
- Number of pages
- 1
- Resource Type
- Abstract
- Language
- English
- Academic Unit
- Materials Science and Engineering
- Other Identifier
- 991022135717704721