Lyu, Y.Yuwono, J.Wang, P.Wang, Y.Yang, F.Liu, S.Zhang, S.Wang, B.Davey, K.Mao, J.Guo, Z.2023-04-272023-04-272023Angewandte Chemie International Edition, 2023; 62(21):e202303011-1-e202303011-101433-78511521-3773https://hdl.handle.net/2440/138118Published May 2023Aqueous Zn-iodine (I2) batteries are attractive for large-scale energy storage. However, drawbacks include, Zn dendrites, hydrogen evolution reaction (HER), corrosion and, cathode 'shuttle' of polyiodines. Here we report a class of N-containing heterocyclic compounds as organic pH buffers to obviate these. We evidence that addition of pyridine /imidazole regulates electrolyte pH, and inhibits HER and anode corrosion. In addition, pyridine and imidazole preferentially absorb on Zn metal, regulating non-dendritic Zn plating /stripping, and achieving a high Coulombic efficiency of 99.6% and long-term cycling stability of 3,200 h at 2 mA cm⁻², 2 mAh cm⁻². It is also confirmed that pyridine inhibits polyiodines shuttling and boosts conversion kinetics for I-/I₂. As a result, the Zn-I₂ full battery exhibits long cycle stability of > 25,000 cycles and high specific capacity of 105.5 mAh g⁻¹ at 10 A g⁻¹. We conclude organic pH buffer engineering is practical for dendrite-free and shuttle-free Zn-I₂ batteries.en© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.Electrolyte additivesorganic pH bufferZn metalZn-iodine batteriesJournal article10.1002/anie.2023030112023-04-27636963Lyu, Y. [0000-0002-3812-3976]Yuwono, J. [0000-0002-0915-0756]Wang, P. [0009-0008-0824-994X]Wang, Y. [0000-0003-3236-1516]Liu, S. [0000-0003-0025-998X]Zhang, S. [0000-0002-3268-5708]Davey, K. [0000-0002-7623-9320]Mao, J. [0000-0002-4787-4261]Guo, Z. [0000-0003-3464-5301]