The core technology of the invention is a solvent extraction synergized complexation process for recovery of cobalt and nickel from spent Li-ion battery. Comparing between traditional solvent extraction and this invention, the cobalt recovery ratio and purity were increased from 70% to 85% and from 70% to 98%, respectively in a single stage. The separation coefficient of cobalt and nickel (βCo/Ni) was increased from 72 to 372.

The practical application includes solvent extraction synergized complexation of Co and Ni. The extraction stages required for traditional solvent extraction were 6~8 stages, but for this invention requires only a single stage. The separation efficiency of cobalt and nickel can be greatly improved, while the acid and alkali consumption, energy consumption, and operating costs can all be decreased.

At present, the total recycling value of waste lithium batteries in Taiwan is about 8 million USD. After the announcement of Executive Yuan stated that starting from 2040 the entire transportation vehicles will only be running on electricity, it is estimated that there will be 154,000 tons per year of waste lithium batteries, and the annual value of recycling cobalt will reach 620 million USD.