Gradient ‐Distributed Nucleation Seeds on Conductive Host for a Dendrite‐Free and High‐Rate Lithium Metal Anode

A 3D carbon nanofiber framework with gradient ‐distributed ZnO particles is proposed for a dendrite‐free and high‐rate lithium metal anode. By introducing ZnO particles as lithium nucleation seeds to reduce the lithium nucleation energy and address the Li‐ion concentrate gradient in the 3D host, a uniform and safe lithium deposition pro cess is achieved. AbstractMuch attention is paid to metal lithium as a hopeful negative material for reversible batteries with a high specific capacity. Although applying 3D hosts can relieve the dendrite growth to some extent, gradient ‐distributed lithium ion in 3D uniform hosts still induces uncontrolled lithium dendrites growth, especially at high lithium capacity and high current density. Herein, a 3D conductive carbon nanofiber framework with gradient‐distributed ZnO particles as nucleation seeds (G‐CNF) to regulate lit hium deposition is proposed. Based on such a unique structure, the G‐CNF electrode exhibits a high average Coulombic efficiency (CE) of 98.1% for 700 cycles at 0.5 mA cm−2. Even at 5 mA cm−2, the G ‐CNF electrode performs a stable cycling process and high CE of 96.0% for over 200 cycles. When the lithium‐deposited G‐CNF (G‐CNF‐Li) anode is applied in a full cell with a commercial LiFePO4 cathode, it exhibits a stable capacity of 115 mAh g−1 and high retention of 95.7% after 300 cycles. Through inducing the gradient ‐distributed nucleation seeds to counter the existing Li‐ion concentrati...

Source: Small - September 16, 2019 Category: Nanotechnology Authors: Yang Nan, Songmei Li, Yongzheng Shi, Shubin Yang, Bin Li Tags: Communication Source Type: research