This work reports on a new aqueous battery consisting of copper and manganese redox chemistries in an acid environment. The battery achieves a relatively low material cost due to ubiquitous availability and inexpensive price of copper and manganese salts. It exhibits an equilibrium potential of ∼1.1 V, and a coulombic efficiency of higher than 94% is obtained at an operating current of 20 mA cm−2. Cyclic tests confirm that the energy efficiency maintains ∼79% with no observable decay at 10 mA cm−2 over 100 cycles. Possessing other advantages such as ease of scalability and capable of using an inexpensive separator, the battery offers a promising solution for large-scale energy storage applications.