(701g) The Primary Aqueous Aluminum-Copper Battery

A novel aqueous primary battery has been developed, comprising a cathode made of copper (Cu) or a copper alloy, and an anode made of aluminum (Al) or an aluminum alloy [Al/Al³⁺, SO₄^2- // Cu²⁺, SO₄^2-/ Cu (Guha S, inventor; 2022 November 06. AQUEOUS COPPER-ALUMINIUM (Cu-Al) PRIMARY BATTERY. Indian Patent Application No. 202231063340)].

The cathode compartment contains an aqueous solution of copper sulfate (CuSO₄) as the electrolyte, while the anode compartment contains an aqueous solution of aluminum sulfate (Al₂(SO₄)₃). These compartments are separated by a ceramic, wood, or inert separator that facilitates ion transport.

To prevent cupric ions (Cu²⁺) from migrating to the aluminum (Al) or aluminum alloy anode compartment, the catholyte and anolyte are supplemented with aqueous potassium nitrate (KNO₃) as a supporting electrolyte. This innovation results in a primary battery with exceptional performance, boasting a specific discharge capacity exceeding 2500 mAh per gram of anode material, and demonstrating highly stable electrochemical behavior.

The battery exhibits an open circuit voltage (OCV) exceeding 0.6 volts per unit cell. It can be constructed in various sizes and excels in self-discharge properties. Notably, it does not generate hydrogen (H₂) gas at the aluminum (Al) or aluminum alloy anode, nor does it deplete the aqueous solvent during discharge. Furthermore, it avoids parasitic corrosion of the aluminum (Al) or aluminum alloy anode.

With an energy density surpassing 600 Wh/kg of anode material and an anodic efficiency reaching 86% or higher, the battery also demonstrates the ability to deliver high electric current densities, exceeding 5 mA per gram of anode material.