Recyclable 3D‐Printed Aqueous Lithium‐Ion Battery

Additive manufacturing, or 3D printing, in energy storage devices such as batteries has the potential to create new form factor small cells that are incorporated into the shape of the device at the design stage. With large‐scale proliferation, sustainable and recyclable materials are needed to avoid used cell waste accumulation, and the cells should have performance metrics that match or exceed existing cells. Inspired by safe aqueous battery chemistries and development in stereolithographic photopolymerization printing methods such as vat polymerization (Vat‐P), a 3D‐printed aqueous lithium‐ion battery developed, using sustainable active cathode and anode materials of LiMn 2 O 4 and FePO 4 ·2H 2 O, which can be fully recycled using a simple combustion method. This battery is designed to allow a stable cycling, higher energy density option compared to a metallic cell of similar construction, and to ensure better intraelectrode electrical conductivity and rigidity necessary for a viable cell, avoiding brittleness sometimes found in all‐in‐one composite‐printed electrodes. The printed cell has a stable cell‐level capacity of 1.86 mAh, better than that of a comparable metallic coin cell of similar internal chemistry, with an average cell voltage just over 1.0 V. Following combustion, the crystalline phase of LiMn 2 O 4 and a mixed phase of some Fe 2 O 3 mixed with a dominant composition of FePO 4 are recovered. All inorganic materials are recovered after combustion.