Integrated Gradient Cu Current Collector Enables Bottom‐Up Li Growth for Li Metal Anodes: Role of Interfacial Structure

• Published in: Advanced science 2023-08, Vol.10 (23), p.e2301288-n/a
• Main Authors: Liu, Yuhang, Li, Yifan, Du, Zhuzhu, He, Chen, Bi, Jingxuan, Li, Siyu, Guan, Wanqing, Du, Hongfang, Ai, Wei
• Format: Article
• Language: English
• Subjects: bottom‐up deposition; Collectors; Contact angle; Cu current collectors; Electrodes; Electrolytes; gradient design; Interfaces; interfacial structure; Li metal batteries; Nanowires; Scanning electron microscopy; Transmission electron microscopy
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202301288

3D Cu current collectors have been demonstrated to improve the cycling stability of Li metal anodes, however, the role of their interfacial structure for Li deposition pattern has not been investigated thoroughly. Herein, a series of 3D integrated gradient Cu‐based current collectors are fabricated by the electrochemical growth of CuO nanowire arrays on Cu foil (CuO@Cu), where their interfacial structures can be readily controlled by modulating the dispersities of the nanowire arrays. It is found that the interfacial structures constructed by sparse and dense dispersion of CuO nanowire arrays are both disadvantageous for the nucleation and deposition of Li metal, consequently fast dendrite growth. In contrast, a uniform and appropriate dispersity of CuO nanowire arrays enables stable bottom Li nucleation associated with smooth lateral deposition, affording the ideal bottom‐up Li growth pattern. The optimized CuO@Cu‐Li electrodes exhibit a highly reversible Li cycling including a coulombic efficiency of up to ≈99% after 150 cycles and a long‐term lifespan of over 1200 h. When coupling with LiFePO4 cathode, the coin and pouch full‐cells deliver outstanding cycling stability and rate capability. This work provides a new insight to design the gradient Cu current collectors toward high‐performance Li metal anodes. 3D integrated gradient CuO@Cu nanowire arrays with varying dispersities are synthesized to investigate the correlation between interfacial structure and Li deposition pattern. It is found that the consistent bottom‐up Li deposition pattern is not only related to the gradient structure that is capable of bottom nucleation, but also requires an ideal interface for facilitating smooth lateral Li deposition.