Future energy storage applications emerging from technological innovations, such as drones and smart devices, require batteries to be small and slender while maintaining high energy density and power capability, fast charging, long cycling/calendar life, and safety. In this study, coaxial-fibers bundled batteries (CFBBs) are proposed, wherein the center is a negative electrode made of carbon fibers, the inner shell is a separator made of Al₂O₃ and polyvinylidene fluoride (PVDF), and the outer shell is a positive electrode. These batteries have flexibility in size and shape by changing the number of bundled electrodes. A 225 mA h CFBB consisting of 288 fiber-electrodes exhibited a high-rate capability of 180 mA h at a 7.6C-rate and a capacity retention of 92% after 100 cycles without marked degradation. A 3.3 mA h CFBB consisting of four fiber-electrodes exhibited 90% capacity retention after 100 cycles. Electrochemical–thermal coupled simulations of CFBBs predicted high safety in the event of an internal short-circuit, and the nail penetration test on the 225 mA h CFBB at 4.2 V demonstrated that the temperature rise was limited to 48 °C by the characteristic safety mechanism. Manufacturing processes to enable mass production are described and a flight test of a drone with four 225 mA h CFBBs is conducted to demonstrate their performance. A flexure test of the CFBBs consisting of 288 fiber-electrodes demonstrated that CFBBs have sufficiently high strength to be applied as the frameworks of drones and wearable devices and as their power sources.

中文翻译：

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同轴纤维束电池的三维电极特性和尺寸/形状灵活性

无人机和智能设备等技术创新带来的未来储能应用，要求电池体积小而纤细，同时保持高能量密度和功率能力、快速充电、长循环/日历寿命和安全性。在这项研究中，提出了同轴纤维束电池（CFBB），其中中心是由碳纤维制成的负极，内壳是由Al ₂ O ₃和聚偏二氟乙烯（PVDF）制成的隔膜，外壳是是正极。通过改变成束电极的数量，这些电池在尺寸和形状上具有灵活性。由 288 个纤维电极组成的 225 mA h CFBB 在 7.6C 倍率下表现出 180 mA h 的高倍率能力，100 次循环后容量保持率为 92%，没有明显退化。由四个纤维电极组成的 3.3 mA h CFBB 在 100 次循环后表现出 90% 的容量保持率。 CFBB 的电化学-热耦合模拟预测了内部短路时的高安全性，并且 225 mA h CFBB 在 4.2 V 下的钉刺测试表明，通过特征安全机制将温升限制在 48 °C 。描述了实现大规模生产的制造工艺，并对配备四个 225 mA h CFBB 的无人机进行了飞行测试，以展示其性能。对由 288 个纤维电极组成的 CFBB 进行的弯曲测试表明，CFBB 具有足够高的强度，可以用作无人机和可穿戴设备的框架及其电源。