Polymer Molecular Engineering Enables Rapid Electron/Ion Transport in Ultra‐Thick Electrode for High‐Energy‐Density Flexible Lithium‐Ion Battery
Polymer Molecular Engineering Enables Rapid Electron/Ion Transport in Ultra‐Thick Electrode for High‐Energy‐Density Flexible Lithium‐Ion Battery
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DOI：
10.1002/adfm.202100434
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发表时间：
2021-03
影响因子：
19
通讯作者：
Yangfan Zhang;Fuzhen Li;Kang Yang;Xiu Liu;Yaoguang Chen;Zhe Lao;K. Mai;Zishou Zhang
中科院分区：
文献类型：
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作者：
Yangfan Zhang;Fuzhen Li;Kang Yang;Xiu Liu;Yaoguang Chen;Zhe Lao;K. Mai;Zishou Zhang
高能量密度的柔性锂离子电池（LIB）是日益增长的柔性和可穿戴电子设备的迫切需求，但传统的层状结构电极中活性材料的面积负载量低。提高活性材料的面积负载量所带来的电子/离子传输缓慢问题的解决仍然是一个巨大的挑战。本文提出了一种乙烯-醋酸乙烯酯共聚物（伊娃），用于为超厚柔性LFP/CNT/伊娃阴极和LTO/CNT/伊娃阳极提供柔性支撑和离子通道，从而实现高能量密度和全柔性LIB。LFP/CNT/伊娃是由伊娃链和CNT在LFP上缠结形成的三元均相结构，LFP含量高达80wt%，厚度可在20 ~ 460 μm范围内调节。与之前的研究形成鲜明对比的是，随着厚度的增加，LFP/CNT/伊娃在0.1 C倍率下基本上提供了160 mAh g−1的恒定比容量，从而实现了高达4.56 mAh cm−2的电容面积容量。基于LFP/CNT/伊娃和LTO/CNT/伊娃的柔性全LIB在交替的平坦和弯曲状态下表现出良好的循环性能。这些发现应该为设计未来可穿戴储能设备的高能量密度柔性LIB开辟新途径。
Flexible lithium‐ion batteries (LIBs) with high energy density are of urgent need for the ever‐increasing flexible and wearable electronic equipments, but limited by the low areal loading of active materials in traditional electrodes with lamellar structure. It is still a great challenge to solve the sluggish electron/ion transport problem caused by increasing the areal loading of active materials. Herein, a kind of ethylene vinyl acetate copolymer (EVA) is proposed to provide flexible supports and ion channels for ultra‐thick flexible LFP/CNT/EVA cathode and LTO/CNT/EVA anode, thereby achieving high energy density and all flexible LIBs. LFP/CNT/EVA shows a ternary homogeneous structure formed by the entanglement of EVA chains and CNT on LFP, which attributes to LFP content up to 80wt% and adjustable thickness from 20 to 460 µm. In sharp contrast to previous studies LFP/CNT/EVA delivers basically the constant specific capacity of ≈160 mAh g−1 at a 0.1 C rate with the thickness increasing, thus achieving ultrahigh areal capacity up to 4.56 mAh cm−2. A flexible full LIBs based on LFP/CNT/EVA and LTO/CNT/EVA is demonstrated and exhibits favorable cycle performance under an alternant flat and bending state. Those findings are supposed to open new avenues for designing high‐energy‐density flexible LIBs for future wearable energy storage devices.