Three years ago, Tesla CEO Elon Musk pledged to halve the cost of batteries and produce a $25,000 electric vehicle for the mass market. Much of the savings was to come from changing how the batteries’ electrodes were produced, using a dry process that would eliminate thousands of gallons of chemicals, solvent and water.

Now, in a new paper, Jeff Dahn, a principal battery engineer at Tesla and physics professor emeritus at Canada’s Dalhousie University, has proposed removing water from another stage of battery manufacturing, which he argues would save even more money. Dahn describes how to make cathode powder—the chemical precursor to the positive electrode, the most expensive component in a battery—using a dry process. Substantial water would still be required to mine nickel, but battery makers would employ virtually no liquid in the subsequent stages of cathode production.