Fiber lithium-ion batteries (FLIBs) hold great promise for powering wearable electronics. However, their practical application is hindered by limited cycle and calendar life, primarily due to the loss of active Li caused by water vapor permeation through the encapsulation layer. To address this challenge, a low-permeability and high-flexibility tetrafluoroethylene hexafluoropropylene copolymer (FEP) tube is presented to continuously encapsulate FLIBs by melting extrusion method. Owing to the inherent hydrophobicity of fluorine resins and appropriate crystallinity of the polymer matrix, FEP tubes exhibited significantly low vapor permeability, with a water vapor transmittance rate (WVTR) of 0.3 mg·day⁻¹·pkg⁻¹, 15 times lower than that of the nylon 12 tubes (4.6 mg·day⁻¹·pkg⁻¹). Leveraging the low permeability and elastic modulus of FEP tubes, FLIBs demonstrate a capacity retention of 80.05% after 180 cycles and exceptional flexibility with a capacity retention of 98.32% after 10 000 bending cycles, showcasing superior performance compared to the conventional polymer tubes (for example, the capacity of PP-FLIBs declined by 20.68% after 30 cycles). This work presents a general and efficient strategy for continuously encapsulating FLIBs, effectively extending their cycle and calendar lifetime of FLIBs, thereby enhancing their practical viability for wearable electronic applications.

中文翻译：

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用于长寿命纤维锂离子电池的低磁导率柔性聚合物管


纤维锂离子电池（FLIB）在为可穿戴电子产品供电方面有着广阔的前景。然而，它们的实际应用受到有限的循环和日历寿命的阻碍，这主要是由于水蒸气渗透通过封装层导致活性锂的损失。为了应对这一挑战，提出了一种低渗透性和高柔韧性四氟乙烯六氟丙烯共聚物（FEP）管，通过熔融挤出方法连续封装 FLIB。由于氟树脂固有的疏水性和聚合物基体适当的结晶度，FEP管材表现出极低的透湿性，水蒸气透过率（WVTR）为0.3 mg·day ⁻¹ ·pkg ⁻¹ ，比尼龙12管低15倍（4.6mg·天 ⁻¹ ·pkg ⁻¹ ）。利用 FEP 管的低渗透性和弹性模量，FLIB 在 180 次循环后表现出 80.05% 的容量保持率，并且具有出色的柔韧性，在 10 000 次弯曲循环后容量保持率为 98.32%，与传统聚合物管相比（例如，30次循环后PP-FLIB的容量下降了20.68%）。这项工作提出了一种持续封装 FLIB 的通用且有效的策略，有效延长了 FLIB 的周期和日历寿命，从而增强了其在可穿戴电子应用中的实际可行性。