Table 1 Different kinds of additives in the electrolyte to improve the performance of Zn electrode.

Polymer

Polyethylene glycol (PEG), polyaniline (PANI), PMMA, polyethyleneimine (PEI), polyvinyl alcohol (PVA), polypyrrole, triton X-100

Adsorb on the surface of Zn electrode and slow down the deposition rate of Zn; increase the overpotential of H₂ evolution

^{121,154,155,156,157}

Surfactant

Sodium dodecyl sulfate (SDS), thiourea (TU), cetyltrimethylammonium bromide (CTAB), tetrabutylammonium bromide (TBAB), ethylenediamine, succinic acid (SA), tartaric acid (TA), citric acid (CA), vanillin

Adsorb on the surface of Zn electrode to slow down the deposition rate of Zn; increase the overpotential of H₂ evolution

^{124,125,158,159,160,161}

Metal cation

Bi³⁺, Pb²⁺, In³⁺

Reduced metal serves as the substrate of Zn deposition and optimize the current distribution of Zn electrode; increase the overpotential of H₂ evolution

^{126,127,130,162,163}