A new shape-conformable battery concept: The 3D printed injectable battery filled with semi-solid electrodes

Shape-conformable batteries are of high interest for a variety of portable electronics. In this work, a new manufacturing concept for cost-effective shape-conformable batteries based on the combination of additive manufacturing (AM) technology and semi-solid electrodes (SSEs) is proposed. The manufacturing process consists in two steps. Firstly, the electrochemical cell is printed by stereolithography-based technique (SLA) and subsequently assembled. In a second step, flowable SSEs are injected into the cells by a double injection mechanism to introduce both SSEs in parallel. While syringe outlets, cell inlets and shape of the cell are found to play an important role in the injection process, formulation of the SSEs are observed to influence the rheological and electrochemical properties. For the proof of concept, a battery having the shape of the logo of our university is fabricated using Zn-based and MnO2-based SSEs achieving high utilization rate (>150 mAh g(MnO2)(-1)) and acceptable cycle stability (0.45% h(-1)) and thus showing the feasibility of the proposed shape-conformable injectable battery. The manufacturing process is finally extended to other battery chemistries leading to improved cycling stability and confirming the versatility of the manufacturing concept.