Cathode-Electrolyte Interface Modification by Binder Engineering for High-Performance Aqueous Zinc-Ion Batteries

Haobo Dong; Ruirui Liu; Xueying Hu; Fangjia Zhao; Liqun Kang; Longxiang Liu; Jianwei Li; Yeshu Tan; Yongquan Zhou; Dan J L Brett; Guanjie He; Ivan P Parkin

doi:10.1002/advs.202205084

Cathode-Electrolyte Interface Modification by Binder Engineering for High-Performance Aqueous Zinc-Ion Batteries

Adv Sci (Weinh). 2023 Feb;10(5):e2205084. doi: 10.1002/advs.202205084. Epub 2022 Dec 16.

Authors

Haobo Dong^{1

2}, Ruirui Liu³, Xueying Hu¹, Fangjia Zhao¹, Liqun Kang⁴, Longxiang Liu¹, Jianwei Li¹, Yeshu Tan¹, Yongquan Zhou³, Dan J L Brett², Guanjie He², Ivan P Parkin¹

Affiliations

¹ Christopher Ingold Laboratory, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK.
² Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, 20 Gordon Street, London, WC1E 7JE, UK.
³ Key Laboratory of Comprehensive and Highly Efficient Util, Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Chinese Academy of Sciences, Xining, Qinghai, 810008, China.
⁴ Materials and Catalysis Laboratory, Department of Chemical Engineering, University College London, London, WC1E 7JE, UK.

Abstract

A stable cathode-electrolyte interface (CEI) is crucial for aqueous zinc-ion batteries (AZIBs), but it is less investigated. Commercial binder poly(vinylidene fluoride) (PVDF) is widely used without scrutinizing its suitability and cathode-electrolyte interface (CEI) in AZIBs. A water-soluble binder is developed that facilitated the in situ formation of a CEI protecting layer tuning the interfacial morphology. By combining a polysaccharide sodium alginate (SA) with a hydrophobic polytetrafluoroethylene (PTFE), the surface morphology, and charge storage kinetics can be confined from diffusion-dominated to capacitance-controlled processes. The underpinning mechanism investigates experimentally in both kinetic and thermodynamic perspectives demonstrate that the COO^- from SA acts as an anionic polyelectrolyte facilitating the adsorption of Zn²⁺ ; meanwhile fluoride atoms on PTFE backbone provide hydrophobicity to break desolvation penalty. The hybrid binder is beneficial in providing a higher areal flux of Zn²⁺ at the CEI, where the Zn-Birnessite MnO₂ battery with the hybrid binder exhibits an average specific capacity 45.6% higher than that with conventional PVDF binders; moreover, a reduced interface activation energy attained fosters a superior rate capability and a capacity retention of 99.1% in 1000 cycles. The hybrid binder also reduces the cost compared to the PVDF/NMP, which is a universal strategy to modify interface morphology.

Keywords: in situ formation; interface engineering; water-soluble binder; zinc-ion batteries.

Abstract

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