The Injectable Battery. A Conceptually New Strategy in Pursue of a Sustainable and Circular Battery Model

Energy storage is being long accepted to play a key role in achieving a sustainable and environmentally-friendly energy and transportation model. Among the various energy storage systems, batteries are attracting increasing attention since they offer a good compromise of energy efficiency, energy density and cost. However, the sus-tainability of an environmentally-friendly model based on batteries is under debate since the recycling processes are costly and energy-demanding. Herein, the injectable battery, in which cathode and anode electrodes are not fixed on a current collector, is for the first time proposed as an innovative concept to facilitate the recycling process and reuse the battery cells. Battery crushing during recycling is not needed for the injectable batteries since battery cells are reused, which leads to significant reduction in number of steps, products, energy and thus battery costs. The proof-of-concept for the envisioned strategy is shown for aqueous injectable batteries (standard and super-concentrated electrolytes Zn – LiFePO4 and LiTi2(PO4)3– LiFePO4), as well as its plausibility for non- aqueous injectable battery (Li – LiFePO4). This new battery concept is expected to be of special interest for future emerging aqueous battery chemistries with low cost of active materials with respect to inactive ones.