Spherical Lithium Deposition Enables High Li-Utilization Rate,Low Negative/Positive Ratio,and High Energy Density in Lithium Metal Batteries |
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Authors: | Caoyu Wang Chunpeng Yang Yahao Du Zaiping Guo Huan Ye |
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Affiliation: | 1. College of Science, Huazhong Agricultural University, Wuhan, 430070 China;2. School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China;3. School of Chemical Engineering & Advanced Materials, The University of Adelaide, Adelaide, SA, 5005 Australia |
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Abstract: | Lithium metal battery promises an attractively high energy density. A high Li-utilization rate of Li metal anode is the prerequisite for the high energy density and avoiding a huge waste of the Li resource. However, the dendritic Li deposition gives rise to “dead Li” and parasitic interfacial reactions, resulting in a low Li utilization rate. Herein, Li deposition is regulated to spherical Li by designing an MXene host with an egg-box structure, suitable curvature, and continuous gradient lithiophilic structure. Because the spherical Li greatly reduces the interfacial side reactions and avoids the formation of dead Li, the Li anode affords a high plating/stripping efficiency. Furthermore, the gradient lithiophilic design results in a bottom-up growth of the spherical Li within the host, safely away from the separator. Thus, the spherical Li anode realizes a long life of >3000 h with a high Li-utilization rate of >90%, stable cycling in full cells at an areal capacity up to 5 mAh cm?2 with a low negative/positive ratio of 0.8, which is critical for high energy density. Such spherical deposition highlights the critical role of the morphological control of alkali metals and provides a viable method to build practical high-energy metal batteries. |
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Keywords: | high energy density high Li utilization lithium metal anodes lithium metal batteries spherical lithium |
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