Stabilizing zinc anode via a chelation and desolvation electrolyte additive

The uncontrollable dendrites growth and intricately water-induced side reactions occurred on zinc anode leads to safety issues and poor electrochemical kinetics, which largely limit the widespread application of zinc-ion batteries (ZIBs). Herein, ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) is utilized as an electrolyte additive to strengthen the reversibility and cycling stability of zinc anode. Experimental results and theoretical calculation demonstrate that the EDTA-2Na presents a much stronger coordination with Zn²⁺ when comparing with H₂O molecular, implying the EDTA-2Na is capable to enter the solvation shell of [Zn(OH₂)₆]²⁺ and coordinate with Zn²⁺ ions, thus achieving a flat and smooth zinc deposition with less by-products (Zn₄SO₄(OH)₆·xH₂O and H₂). Consequently, the zinc symmetric battery with EDTA-2Na additive delivers an excellent cycling stability up to 1800 h under current density of 1 mA cm^-2, and the hydrogen evolution reaction (HER), corrosion, by-product issues are significantly inhibited. Moreover, the rate performance and stability of coin-type and pouch-type Zn||MnO₂/graphite batteries are significantly boosted via EDTA-2Na additive (248 mAh g^-1 at 0.1 A g^-1, 81.3% after 1000 cycles at a A g^-1). This kind of electrolyte additive with chelation and desolvation functions shed lights on strategies of improving zinc anode stability for further application of ZIBs. © 2021 Central South University.