Ultra-efficient polymer binder for silicon anode in high-capacity lithium-ion batteries
Ultra-efficient polymer binder for silicon anode in high-capacity lithium-ion batteries
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DOI：
10.1016/j.nanoen.2020.104804
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发表时间：
2020-07-01
期刊：
影响因子：
17.6
通讯作者：
Cao, Peng-Fei
中科院分区：
文献类型：
--
作者：
Gao, Shilun;Sun, Feiyuan;Cao, Peng-Fei
作为一种极具潜力的高容量锂离子电池（LIBs）负极材料，硅（Si）的低电子导电性和大体积变化使得基于浆料涂覆的硅基电极需要高含量的“惰性”材料，并且会出现快速的容量衰减。在此，一种通过一步缩合反应合成的聚亚胺被证明是一种超高效的聚合物粘结剂，能够解决上述问题。含有聚亚胺粘结剂的硅电极展现出优异的电化学性能：在2 A g⁻¹的电流密度下，经过1000次循环后，脱锂比容量为804.4 mAh g⁻¹，容量保持率为82.4%。聚亚胺粘结剂对于硅电极的高效性还通过“活性”材料与“惰性”材料的超高重量比（R - A/I）得以证明。含有95 wt%硅的电极（95Si/聚亚胺，R - A/I = 19）在400 mA g⁻¹的电流密度下，经过200次循环后，显示出2114 mAh g⁻¹的可逆脱锂容量（容量保持率为80.4%）。即使在2 A g⁻¹的高电流密度下，经过500次循环后也能获得1087.8 mAh g⁻¹的脱锂容量。利用分子模拟和原子力显微镜（AFM）压痕来研究聚亚胺粘结剂的超高效性。凭借简单的制造工艺和超高效的粘结剂性能，所设计的聚亚胺粘结剂对于实现低成本、高容量且循环寿命长的锂离子电池无疑具有重要意义。
As a highly promising anode material for high-capacity lithium-ion batteries (LIBs), the low electronic conductivity and large volume variation of silicon (Si) make the slurry-coating Si based electrode requiring high content of "inert" materials and suffering rapid capacity fading. Herein, a polyimine, synthesized via one-step condensation reaction, has been demonstrated as an ultra-efficient polymer binder that can resolve the above issues. The polyimine binder containing Si electrode delivers superior electrochemical performance: a delithiation specific capacity of 804.4 mAh g(-1) with capacity retention of 82.4% after 1000 cycles at the current density of 2 A g(-1). The high efficiency of polyimine binder for Si electrode has also been demonstrated with ultrahigh weight ratio of "active" material to "inert" material (R-A/I). The electrode with 95 wt% of Si (95Si/Polyimine, R-A/I = 19) reveals a reversible delithiation capacity of 2114 mAh g(-1) (capacity retention -80.4%) over 200 cycles at the current density of 400 mA g(-1). Even at the high current density of 2 A g(-1), a delithiation capacity of 1087.8 mAh g(-1) after 500 cycles can be obtained. Molecular simulations and atomic force microscopy (AFM) indentation are utilized to investigate the ultra-efficiency of polyimine binder. With simple manufacturing process and ultra-efficient binder performance, the designed polyimine binder will be definitely meaningful in achieving low-cost and high-capacity LIBs with prolonged cycle life.