A carbon-based 3D current collector with surface protection for Li metal anode
A carbon-based 3D current collector with surface protection for Li metal anode
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DOI：
10.1007/s12274-017-1461-2
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发表时间：
2017-03
期刊：
影响因子：
9.9
通讯作者：
Ying Zhang;Boyang Liu;Emily Hitz;W. Luo;Yonggang Yao;Yiju Li;J. Dai;Chaoji Chen;Yanbin Wang-Yanbin
中科院分区：
文献类型：
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作者：
Ying Zhang;Boyang Liu;Emily Hitz;W. Luo;Yonggang Yao;Yiju Li;J. Dai;Chaoji Chen;Yanbin Wang-Yanbin
锂金属被认为是锂离子电池的理想负极材料，因为它具有最高的比容量和最低的氧化还原电位。然而，锂枝晶的生长、固体电解质界面不稳定、库仑效率低以及安全隐患严重阻碍了金属锂阳极的实际应用。在此，我们提出了一个三维（3D）碳纳米管海绵（CNTS）作为锂沉积宿主。碳纳米管的高比表面积使电荷分布均匀，有利于锂成核，并使有效电流密度最小化，从而克服枝晶生长。通过原子层沉积（atomic layer deposition， ALD）在碳纳米管表面增加一层共形al2o3层，由于其良好的化学稳定性和较高的机械强度，可以有效地保护锂金属电极/电解质界面。Li@ALD-CNTS电极在1.0 mA·cm-2下循环100 h，其过电位在16 ~ 30 mV之间，表现出稳定的电压分布。此外，在有机碳酸盐电解质中，在1.0 mA·cm - 2下循环80次后，电极表现出无枝晶的形貌，库仑效率为92.4%，从而表现出优于平面集热器的电化学稳定性。我们的研究结果为合理设计集流器以获得稳定的锂金属阳极提供了重要的策略。
Lithium metal is considered the ideal anode material for Li-ion-based batteries because it exhibits the highest specific capacity and lowest redox potential for this type of cells. However, growth of Li dendrites, unstable solid electrolyte interphases, low Coulombic efficiencies, and safety hazards have significantly hindered the practical application of metallic Li anodes. Herein, we propose a three-dimensional (3D) carbon nanotube sponge (CNTS) as a Li deposition host. The high specific surface area of the CNTS enables homogenous charge distribution for Li nucleation and minimizes the effective current density to overcome dendrite growth. An additional conformal Al2O3layer on the CNTS coated by atomic layer deposition (ALD) robustly protects the Li metal electrode/electrolyte interface due to the good chemical stability and high mechanical strength of the layer. The Li@ALD-CNTS electrode exhibits stable voltage profiles with a small overpotential ranging from 16 to 30 mV over 100 h of cycling at 1.0 mA·cm–2. Moreover, the electrodes display a dendrite-free morphology after cycling and a Coulombic efficiency of 92.4% over 80 cycles at 1.0 mA·cm–2in an organic carbonate electrolyte, thus demonstrating electrochemical stability superior to that of planar current collectors. Our results provide an important strategy for the rational design of current collectors to obtain stable Li metal anodes.