摘要
The severe lithium(Li)dendrite growth leads to poor cycling stability and serious safety hazards of Li metal batteries,which completely impedes their practical applications.Herein,a novel Li nucleation-diffusion-growth mechanism based on Li-Sn alloy/Li_(3) N electrolyte(LS/LN)composite interface layer is proposed,which synergistically guides the horizontal deposition of Li to suppress the vertical growth of Li dendrite and side reactions with the electrolyte.The lithiophilic Li-Sn alloy captures Li ions to nucleate preferentially on the alloy sites,and simultaneously the Li_(3) N with low diffusion energy barrier and high Li-ion conductivity efficiently transports Li ions to nucleation sites during Li plating,consequently promoting the Li horizontal deposition.As a result,the LS/LN-Li symmetric cells can stably cycle 1600 h even at a high current density of 5 mA cm^(-2) and deposition capacity of 5 mA h cm^(-2).The LiFePO_(4)|LS/LN-Li cells with a high loading of 8.2 mg cm^(-2) present a high capacity retention of 93.4%after 1000 cycles,much higher than that using bare Li(64.8%).Furthermore,the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)|LS/LN-Li cells present more excellent cycling stability than the cells using bare Li.The Li nucleation-diffusion-growth mechanism opens a promising route to solve the challenge of the vertical growth of Li dendrite and achieve highly stable Li metal batteries.
严重的锂枝晶生长导致锂金属电池的循环稳定性差、安全隐患大,完全阻碍了其实际应用.本文提出了一种基于Li-Sn/Li_(3)N复合界面层的锂形核-扩散-生长机制,利用两组分的协同作用引导锂的水平沉积,从而抑制锂枝晶的垂直生长以及锂金属与电解液之间的副反应.在锂沉积过程中,亲锂的Li-Sn合金优先捕获Li+在合金位点上形核,同时具有低扩散能垒和高锂离子电导率的Li_(3)N有效地将锂离子传输至形核位点,最终促进锂的横向生长.因此,即使在5 m A cm^(-2)的高电流密度和5 m A h cm^(-2)的大沉积容量下,组装的对称电池也可以稳定循环1600 h.与负载高达8.2 mg cm^(-2)的Li Fe PO_(4)正极组装的电池,在循环1000圈以后,容量保持率为93.4%,远高于未修饰锂片(64.8%).此外,Li-Sn/Li_(3)N修饰的锂负极与Li Ni_(0.8)Co_(0.1)Mn_(0.1)O_(2)正极组装的电池循环稳定性也明显优于未修饰锂片组装的电池.锂成核-扩散-生长机制为解决垂直生长的锂枝晶难题、实现高稳定锂金属电池开辟了一条有前景的途径.
作者
Jing Yu
Kai Shi
Siwei Zhang
Danfeng Zhang
Likun Chen
Song Li
Jiabin Ma
Heyi Xia
Yan-Bing He
俞静;石凯;张思伟;张丹丰;陈立坤;李松;马家宾;夏和颐;贺艳兵(Shenzhen Geim Graphene Center,Tsinghua Shenzhen International Graduate School,Shenzhen 518055,China;Laboratory of Advanced Materials,School of Materials Science and Engineering,Tsinghua University,Beijing 100084,China;Shenzhen Environmental Science and New Energy Technology Engineering Laboratory,Tsinghua-Berkeley Shenzhen Institute(TBSI),Tsinghua University,Shenzhen 518055,China)
基金
supported by the Key-Area Research and Development Program of Guangdong Province (2020B090919001)
the National Natural Science Foundation of China (U2001220)
Local Innovative Research Teams Project of Guangdong Pearl River Talents Program (2017BT01N111)
Shenzhen Technical Plan Project (JCYJ20180508152210821, JCYJ20170817161221958, and JCYJ20180508152135822)
the All-Solid-State Lithium Battery Electrolyte Engineering Research Center (XMHT202002030)
Shenzhen Graphene Manufacturing Innovation Center (201901161513)
