材料科学
过电位
法拉第效率
石墨烯
导电体
阳极
分离器(采油)
热失控
复合材料
化学工程
纳米技术
电极
热力学
电化学
功率(物理)
化学
物理
工程类
物理化学
电池(电)
作者
Duzhao Han,Xiaowei Wang,Yanan Zhou,Jiyong Zhang,Zhongxin Liu,Zichun Xiao,Jiangqi Zhou,Zhen Wang,Jiangfeng Zheng,Zhanhui Jia,Bingbing Tian,Jingying Xie,Zhaolin Liu,Wei Tang
标识
DOI:10.1002/aenm.202201190
摘要
Abstract Practical lithium metal batteries (LMBs) are still far from market readiness, as a result of the severe Li degradation and safety issues caused by Li dendrites. Herein, by studying the thermodynamic behavior of lithium deposition, it is unveiled that the tip area of Li metal has an increasing heat generation rate as a function of the deposition time and overpotential. This triggers the emergence of the accumulated overpotential heat and local temperature “hotspots” due to poor local thermal diffusion, which exacerbates the undesirable irregular Li deposition and dendrite growth. To address this issue, a thermally conductive graphene‐coated separator is constructed to eliminate these local hotspots. The graphene layer affords timely diffusion of local heat generated by irregular Li growth and incipient dendrite formation, achieving the stable and uniform lithium deposition to deter further degradation. As a result, the Li metal, suffering a drastic Coulombic efficiency (CE) decay to ≈60% using a conventional separator, can be recovered for continual cycling with a high CE of >95%. Notably, the corresponding Li||LiNi 0.8 Mn 0.1 Co 0.1 O 2 cells present high capacity retention and recovery. This study highlights the thermodynamic factor of Li dendrite‐induced local heat and its elimination to preclude Li anode deterioration, which provides insight into Li metal protection strategies for high performance LMBs.
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