Zhang Jia-Hao, Chang Yu, Yu Jia-Cheng, Wang Yong-Xin, Huang Zhi-Long, Yao Ming, Jiang Zhi-Guo, Xie Gang, Qu Jin
State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Beijing Key Laboratory of Advanced Functional Polymer Composites, Beijing University of Chemical Technology, Beijing 100029, China.
ACS Appl Mater Interfaces. 2024 Aug 14;16(32):42332-42342. doi: 10.1021/acsami.4c10070. Epub 2024 Jul 31.
Lithium metal anode has attracted wide attention due to its ultrahigh theoretical specific capacity, lowest reduction potential, and low density. However, uncontrollable dendritic growth and volume change caused by uneven Li deposition still seriously hinder the large-scale commercial application of lithium metal batteries, even causing serious battery explosions and other safety problems. Hence, gold nanoparticles with a gradient distribution anchored on 3D carbon fiber paper (CP) current collectors followed by the encapsulation of polydopamine (PDA) (CP/Au/PDA) are constructed for stable and dendrite-free Li metal anodes for the first time. Significantly, lithiophilic Au nanoparticles showing a gradient distribution in the carbon fiber paper could guide the transfer of Li from the outside to the inside of the CP/Au/PDA electrode as well as lower the nucleation overpotential of Li, thereby obtaining the uniform Li deposition. Meanwhile, the PDA layer could in situ be converted to Li-PDA which could serve as an efficient Li conductor to further facilitate uniform Li transport among the whole CP/Au/PDA electrode. Besides, 3D carbon fiber paper could effectively accommodate the volume change during the plating/stripping process of Li metal. As a result, CP/Au/PDA electrodes deliver a low nucleation overpotential (∼9 mV) and a high Coulombic efficiency (mean value of ∼98.8%) at a current density of 1 mA cm with the capacity of 1 mA h cm. Furthermore, Li@CP/Au/PDA electrodes also can demonstrate an ultralow voltage hysteresis (∼20 mV) and a long cycle life (1000 h) in symmetric cells. Finally, with LiFePO (LFP) as the cathode, the Li@CP/Au/PDA-LFP full cell delivers a high discharge capacity of 136 mA h g even after 350 cycles at 1C, exhibiting a per cycle loss as low as 0.01%. This gradient lithium ion regulation current collector is of great significance for the development of lithium metal anodes.
锂金属负极因其超高的理论比容量、最低的还原电位和低密度而备受关注。然而，锂不均匀沉积导致的不可控枝晶生长和体积变化仍然严重阻碍了锂金属电池的大规模商业应用，甚至引发严重的电池爆炸等安全问题。因此，首次构建了锚定在三维碳纤维纸（CP）集流体上且具有梯度分布的金纳米颗粒，随后包覆聚多巴胺（PDA）（CP/Au/PDA），用于制备稳定且无枝晶的锂金属负极。值得注意的是，在碳纤维纸中呈现梯度分布的亲锂金纳米颗粒能够引导锂从CP/Au/PDA电极外部向内部转移，同时降低锂的成核过电位，从而实现锂的均匀沉积。与此同时，PDA层可原位转化为Li-PDA，其可作为高效的锂导体，进一步促进整个CP/Au/PDA电极中锂的均匀传输。此外，三维碳纤维纸能够有效容纳锂金属在电镀/脱镀过程中的体积变化。结果表明，CP/Au/PDA电极在电流密度为1 mA cm且容量为1 mA h cm时，具有低成核过电位（约9 mV）和高库仑效率（平均值约98.8%）。此外，Li@CP/Au/PDA电极在对称电池中还能表现出超低的电压滞后（约20 mV）和长循环寿命（1000 h）。最后，以磷酸铁锂（LFP）为正极，Li@CP/Au/PDA-LFP全电池即使在1C下循环350次后仍具有136 mA h g的高放电容量，每循环损失低至0.01%。这种梯度锂离子调控集流体对锂金属负极的发展具有重要意义。
