Stainless steel as low-cost high-voltage cathode via stripping/deposition in metal-lithium battery

Despite advances in traditional lithium-ion batteries in the past decades, its high cost has always been a bottleneck for large-scale applications. In this work, we demonstrate it is possible to replace expensive cathodes such as LiCoO₂ with inexpensive stainless steel to store energy via a stripping/deposition mechanism: during charging, the stainless-steel cathode removes charges by releasing metal ions into the electrolyte, and during discharge, the metal ions re-deposit on the electrode reversibly. An anion exchange membrane allows passage of anions to balance the charge and prevents cross-over of cations. We show here a battery with a stainless-steel cathode and a lithium metal anode with a high discharge voltage of 2.5 V and good reversibility. We also study the mechanism at the stainless-steel electrode, as well as the kinetics of the battery system. Our work can potentially reduce the cost of energy storage by turning common construction materials into cathode materials. In addition, a metal cathode undergoing stripping/deposition gives a theoretical energy density comparable to lithium-sulfur batteries and provides a new exciting direction for future energy storage development.