Program of Materials Science and Engineering, Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10025, USA.
School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China.
Adv Mater. 2018 Mar;30(12):e1704947. doi: 10.1002/adma.201704947. Epub 2018 Jan 31.
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 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.
柔性和可穿戴电子设备的快速发展对高性能柔性电池提出了持续的要求。最近已经取得了很大的进展，但如何同时获得显著的灵活性和高能量密度仍然是一个巨大的挑战。在这里，报道了一种制造脊柱状柔性锂离子电池的简单且可扩展的方法。一个厚的、刚性的部分通过缠绕电极来储存能量，对应于动物的脊椎，而一个薄的、未缠绕的、灵活的部分作为骨髓将所有脊柱状的电池堆叠连接在一起，为整个电池提供了极好的灵活性。由于刚性电极部分的体积明显大于柔性连接部分，因此这种柔性电池的能量密度可以超过传统包装的 85%。考虑到封装，展示了一个非优化的柔性电池，其能量密度为 242 Wh L，这是使用相同组件的标准棱柱形电池的 86.1%。由于这种合理的仿生设计，该电池还成功地经受住了苛刻的动态机械负荷测试。机械模拟结果揭示了潜在的机制：所报道设计的最大应变（≈0.08%）明显小于传统堆叠电池（≈1.1%）。这种新方法为在柔性设备中的应用提供了巨大的前景。
