柔性锂硫电池凭借其高能量密度和低成本的优势，被认为是可穿戴电子设备中储能器件最有希望的候选者之一。然而，锂硫电池中存在着以负极锂枝晶生长、正极多硫化物穿梭等问题导致的性能衰减问题，以及电池内部短路引发的热失控和起火燃烧等安全问题。这些问题严重制约着柔性锂硫电池的发展和实际应用。电池隔膜和电解质作为正、负极之间离子传输的介质，在使用过程中同时接触电池正负极两侧。对隔膜/电解质进行设计可同时解决上述正、负极存在的挑战，从而提升柔性锂硫电池的电化学性能及安全性。开发能够抑制锂枝晶生长、防止多硫化物穿梭、且不可燃烧的隔膜是推动柔性锂硫电池发展的有效措施。本项工作设计制备了一种不易燃的多功能双面隔膜，具有高导热性、热稳定性、自熄性、良好的电解液渗透性、均匀的锂沉积和多硫化物穿梭抑制作用。隔膜由含十溴二苯乙烷的聚丙烯腈纤维膜以及用于阻挡锂枝晶的氮化硼功能层和用于促进正极活性物质转化的还原氧化石墨烯功能层组成。基于以上多功能隔膜设计，硫含量为2.7 mg cm?2 的锂硫电池在0.1 C下循环 100 次后的比容量为916.8 mA h g?1，并且锂硫电池能在间歇性热冲击下和连续弯折下保持稳定的性能。此外，硫含量为8 mg的锂硫软包电池在弯曲条件下表现出6.3 mA h的容量。为了进一步提升柔性锂硫电池的安全性与一体化程度，开发具有高离子电导率且能够抑制多硫穿梭的固态电解质是有效的措施。本论文进一步设计合成了一种聚环氧乙烷-聚丙烯腈（PEO-PAN）共聚物膜电解质，其中PAN纤维既充当填料，使PEO在常温下无序排列，又充当交联剂与PEO分子交联。这种结构不仅实现了高离子电导率、高机械强度并有效阻挡锂枝晶生长，而且通过PEO和PAN交联过程中形成的C=N-O官能团对多硫化物的强烈吸附作用抑制了多硫化物穿梭，从而显著提高了锂硫电池的安全性、循环稳定性和倍率能力。基于这种电解质高柔韧性和高结合强度的特点，柔性锂硫电池在1000次弯曲循环后仍能保持96 %以上的容量。

With the advantages of high energy density and low cost, flexible lithium-sulfur batteries (LSBs) are considered as one of the most promising candidates for energy storage devices in wearable electronic devices. However, LSBs have the problems of performance degradation, caused by the growth of lithium dendrites in the anode and the polysulfides shuttling in the cathode, and safety issues such as thermal runaway and combustion induced by internal short circuits. These problems seriously restrict the development and practical application of flexible LSBs. The battery separator and the electrolyte, as the medium for ion transport between the cathode and anode, are in contact with both them in the battery at the same time during cycling. Therefore, it is possible to solve the problems existing in the cathode and anode of LSBs from the perspective of developing advanced separators and electrolytes, thus improving the electrochemical performance and the safety of flexible LSBs.The development of separators that can suppress lithium dendrite growth as well as polysulfide shuttling, and are incombustible, which is an effective strategy to promote the development of flexible LSBs. In this work, a nonflammable multifunctional Janus separator with high thermal stability, high thermal conductivity, self-extinguishing capability, good electrolyte infiltration, uniform lithium deposition, and efficient polysulfide shuttling inhibition, is designed and fabricated. The separator is composed of polyacrylonitrile fiber membrane containing flame-retardant decabromodiphenyl ethane as well as functional layers of boron nitride for suppressing lithium dendrite growth and reduced graphene oxide for accelerating the sulfur convention kinetics. As a result, the LSB with a sulfur mass loading of 2.7 mg cm?2 delivers a specific capacity of 916.8 mA h g?1 after 100 cycles at 0.1 C. The LSB maintains a stable performance during intermittent thermal shock and continues bending. Moreover, the lithium-sulfur pouch cell with a sulfur mass loading of 8 mg exhibits a high capacity of 6.3 mA h under bending conditions.To further improve the flexibility and promote the integration of flexible LSBs, the development of solid-state electrolytes that have high ionic conductivity and the ability to inhibit polysulfide shuttling is an efficient strategy. In this work, a poly(ethylene oxide)-polyacrylonitrile (PEO-PAN) copolymer membrane electrolyte is designed and synthesized, in which the PAN fiber not only acts as a filler to make PEO disorderly arranged at room temperature, but also acts as a cross-linking agent to cross-link with PEO molecules. This structure not only provides improved ionic conductivity, high mechanical strength and effective lithium dendrite blocking, it also inhibits polysulfide shuttling as a result of strong polysulfide adsorption by the C=N?O functional groups formed during the PEO and PAN crosslinking process, which significantly improves the safety, cycling stability and rate performance of the LSBs. Based on the high flexibility and high bonding strength of this electrolyte, the flexible LSB can maintain more than 96 % of its capacity after 1000 bending cycles.