Copper-coordinated cellulose ion conductors for solid-state batteries
Copper-coordinated cellulose ion conductors for solid-state batteries
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DOI：
10.1038/s41586-021-03885-6
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发表时间：
2021-10
期刊：
影响因子：
64.8
通讯作者：
Chunpeng Yang;Qisheng Wu;Weiqi Xie;Xin Zhang;Alexandra H. Brozena;Jin Zheng;Mounesha N. Garaga
中科院分区：
文献类型：
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作者：
Chunpeng Yang;Qisheng Wu;Weiqi Xie;Xin Zhang;Alexandra H. Brozena;Jin Zheng;Mounesha N. Garaga
尽管固态锂（Li）金属电池具有高能量密度和安全性，但现有的固体离子导体无法满足电池运行的严格要求。无机离子导体允许快速离子传输，但其刚性和脆性阻碍了与电极的良好界面接触。相反，锂金属稳定的聚合物离子导体通常提供更好的界面相容性和机械耐受性，但由于离子传输与聚合物链1、2、3的运动的耦合，通常离子电导率较差。在这里，我们报告了通过分子通道工程实现高性能固体聚合物离子导体的一般策略。通过铜离子（Cu 2+）与一维纤维素纳米原纤维的配位，我们表明，通常离子绝缘的纤维素内分子通道的打开使得Li + 离子能够沿着聚合物链快速传输。除了高Li+电导率（室温下沿分子链方向为1.5×10−3西门子/厘米）外，Cu 2+ 配位纤维素离子导体还表现出高迁移数（0.78，而其他聚合物2为0.2-0.5）和宽的电化学稳定性窗口（0-4.5伏），可以容纳锂金属阳极和高压阴极。这种一维离子导体还允许离子渗透在厚的LiFePO 4 固态阴极中，用于高能量密度的电池中。此外，我们还验证了这种分子通道工程方法与其他聚合物和阳离子的普遍性，实现了类似的高电导率，其影响可能超出安全、高性能固态电池的范围。
Although solid-state lithium (Li)-metal batteries promise both high energy density and safety, existing solid ion conductors fail to satisfy the rigorous requirements of battery operations. Inorganic ion conductors allow fast ion transport, but their rigid and brittle nature prevents good interfacial contact with electrodes. Conversely, polymer ion conductors that are Li-metal-stable usually provide better interfacial compatibility and mechanical tolerance, but typically suffer from inferior ionic conductivity owing to the coupling of the ion transport with the motion of the polymer chains 1, 2, 3. Here we report a general strategy for achieving high-performance solid polymer ion conductors by engineering of molecular channels. Through the coordination of copper ions (Cu 2+) with one-dimensional cellulose nanofibrils, we show that the opening of molecular channels within the normally ion-insulating cellulose enables rapid transport of Li+ ions along the polymer chains. In addition to high Li+ conductivity (1.5× 10− 3 siemens per centimetre at room temperature along the molecular chain direction), the Cu 2+-coordinated cellulose ion conductor also exhibits a high transference number (0.78, compared with 0.2–0.5 in other polymers 2) and a wide window of electrochemical stability (0–4.5 volts) that can accommodate both the Li-metal anode and high-voltage cathodes. This one-dimensional ion conductor also allows ion percolation in thick LiFePO 4 solid-state cathodes for application in batteries with a high energy density. Furthermore, we have verified the universality of this molecular-channel engineering approach with other polymers and cations, achieving similarly high conductivities, with implications that could go beyond safe, high-performance solid-state batteries.