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The class of two-dimensional metal carbides and nitrides known as MXenes offer a distinct manner of property tailoring for a wide range of applications. The ability to tune the surface chemistry for expanding the property space of MXenes is thus an important topic, although experimental exploration of surface terminals remains a challenge. Here, we synthesized Ti₃C₂ MXene with unitary, binary, and ternary halogen terminals, e.g., −Cl, −Br, −I, −BrI, and −ClBrI, to investigate the effect of surface chemistry on the properties of MXenes. The electrochemical activity of Br and I elements results in the extraordinary electrochemical performance of the MXenes as cathodes for aqueous zinc ion batteries. The −Br- and −I-containing MXenes, e.g., Ti₃C₂Br₂ and Ti₃C₂I₂, exhibit distinct discharge platforms with considerable capacities of 97.6 and 135 mAh·g^–1. Ti₃C₂(BrI) and Ti₃C₂(ClBrI) exhibit dual discharge platforms with …