The rapid development of flexible and wearable electronics proposes the persistent requirements of high-performance flexible batteries. Much progress has been achieved recently, but how to obtain remarkable flexibility and high energy density simultaneously remains a great challenge. Here, a facile and scalable approach to fabricate spine-like flexible lithium-ion batteries is reported. A thick, rigid segment to store energy through winding the electrodes corresponds to the vertebra of animals, while a thin, unwound, and flexible part acts as marrow to interconnect all vertebra-like stacks together, providing excellent flexibility for the whole battery. As the volume of the rigid electrode part is significantly larger than the flexible interconnection, the energy density of such a flexible battery can be over 85% of that in conventional packing. A nonoptimized flexible cell with an energy density of 242 Wh L−1 is demonstrated with packaging considered, which is 86.1% of a standard prismatic cell using the same components. The cell also successfully survives a harsh dynamic mechanical load test due to this rational bioinspired design. Mechanical simulation results uncover the underlying mechanism: the maximum strain in the reported design (≈0.08%) is markedly smaller than traditional stacked cells (≈1.1%). This new approach offers great promise for applications in flexible devices.
G.Y.Q. and B.Z. contributed equally to this work. Y.Y. acknowledges support from startup funding by Columbia University. This work is supported by the NSFMRSEC program through Columbia in the Center for Precision Assembly of Superstratic and Superatomic Solids (DMR-1420634) and sponsored by the China Scholarship Council (CSC) graduate scholarship. The photography and camera services are offered by Teng Yang NYC Media Studio and Jane Nisselson from Columbia Engineering. The authors would like to acknowledge support from Prof. Kristin Myers, Prof. Arvind Narayanaswamy and Dr. Charles Jayyosi of Department of Mechanical Engineering at Columbia University on mechanical measurement. Note: The y axis labels in Figure 2c,e and in 3d,e were corrected to read “Full Cell Voltage (V)”, i.e., for half cells, on March 19, 2018, after initial publication online. The supporting information was also corrected.
- energy density
- flexible batteries
- lithium-ion batteries