Ion/Electron Redistributed 3D Flexible Host for Achieving Highly Reversible Li Metal Batteries,Small

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Ion/Electron Redistributed 3D Flexible Host for Achieving Highly Reversible Li Metal Batteries
Small ( IF 13.0 ) Pub Date : 2022-06-24 , DOI: 10.1002/smll.202107641
Huai Jiang ₁ , Yangen Zhou ₁ , Caohong Guan ₂ , Maohui Bai ₁ , Furong Qin ₁ , Maoyi Yi ₁ , Jie Li ₁ , Bo Hong _{1,

3} , Yanqing Lai _{1,

3}

Affiliation

3D carbon frameworks are promising hosts to achieve highly reversible lithium (Li) metal anodes, whereas insufficient effects are attributed to their single electron conductivity causing local aggregating of electron/Li⁺ and uncontrollable Li dendrites. Herein, an ion/electron redistributed 3D flexible host is designed by lithiophilic carbon fiber cloth (CFC) modified with metal–organic framework (MOF)-derived porous carbon sheath with embedded CoP nanoparticles (CoP-C@CFC). Theory calculations demonstrate the strong binding energy and plenty of charge transfer from the reaction between CoP and Li atom are presented, which is beneficial to in situ construct a Li₃P@Co ion/electron conductive interface on every single CoP-C@CFC. Thanks to the high ionic conductive Li₃P and electron-conductive Co nanoparticles, the rapid dispersion of Li⁺ and obviously reduced local current density can be achieved simultaneously. Furthermore, in situ optical microscopy observations display obvious depression for volume expansion and Li dendrites. As expected, a miraculous average Coulombic efficiency (CE) of 99.96% over 1100 cycles at 3 mA cm^-2 and a low overpotential of 11.5 mV with prolonged cycling of over 3200 h at 20% depth of discharge are successfully obtained. Consequently, the CoP-C@CFC-Li||LiFePO₄ full cells maintain a capacity retention of 95.8% with high CE of 99.96% over 500 cycles at 2 C and excellent rate capability.

中文翻译：

用于实现高度可逆锂金属电池的离子/电子再分布 3D 柔性主体

3D 碳框架是实现高度可逆的锂 (Li) 金属负极的有希望的主体，而效果不足的原因是它们的单电子导电性导致电子/Li ⁺的局部聚集和不可控的锂枝晶。在此，离子/电子再分布的3D柔性主体是由金属有机框架（MOF）衍生的多孔碳鞘和嵌入的CoP纳米粒子（CoP-C@CFC）改性的亲锂碳纤维布（CFC）设计的。理论计算表明，CoP与Li原子之间的反应具有很强的结合能和大量的电荷转移，有利于在每个CoP-C@CFC上原位构建Li _{3 P@Co离子/电子导电界面。}由于具有高离子导电性的 Li ₃P和电子导电Co纳米粒子、Li ⁺的快速分散和明显降低的局部电流密度可以同时实现。此外，原位光学显微镜观察显示体积膨胀和锂枝晶明显下降。^{正如预期的那样，在 3 mA cm -2}的1100 次循环中，神奇的平均库仑效率 (CE) 达到了 99.96%，在 20% 的放电深度下，在超过 3200 小时的长时间循环下，成功获得了 11.5 mV 的低过电位。因此，CoP-C@CFC-Li||LiFePO ₄全电池在 2 C 下经过 500 次循环后仍保持 95.8% 的容量保持率和 99.96% 的高 CE 以及优异的倍率性能。

更新日期：2022-06-24

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