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Aqueous rechargeable batteries have attracted attention owning to their advantages of safety, low cost, and sustainability, while the limited electrochemical stability window (1.23 V) of water leads to their failure in competition with organic‐based lithium‐ion batteries. Herein, we report an alkali–acid Zn–PbO2 hybrid aqueous battery obtained by coupling an alkaline Zn anode with an acidic PbO2 cathode. It shows the capability to deliver an impressively high open‐circuit voltage (Voc) of 3.09 V and an operate voltage of 2.95 V at 5 mA cm−2, thanks to the contribution of expanding the voltage window and the electrochemical neutralization energy from the alkali–acid asymmetric‐electrolyte hybrid cell. The hybrid battery can potentially deliver a large area capacity over 2 mAh cm−2 or a high energy density of 252.39 Wh kg−1 and shows almost no fading in area capacity over 250 charge–discharge cycles. [ABSTRACT FROM AUTHOR]