The commercialization of high‐energy Li‐metal batteries is impeded by Li dendrites formed during electrochemical cycling and the safety hazards it causes. Here, a novel porous copper current collector that can effectively mitigate the dendritic growth of Li is reported. This porous Cu foil is fabricated via a simple two‐step electrochemical process, where Cu‐Zn alloy is electrodeposited on commercial copper foil and then Zn is electrochemically dissolved to form a 3D porous structure of Cu. The 3D porous Cu layers on average have a thickness of ≈14 um and porosity of ≈72%. This current collector can effectively suppress Li dendrites in cells cycled with a high areal capacity of 10 mAh cm−2and under a high current density of 10 mA cm−2. This electrochemical fabrication method is facile and scalable for mass production. Results of advanced in situ synchrotron X‐ray diffraction reveal the phase evolution of the electrochemical deposition and dealloying processes.
A vertically aligned carbon nanofiber (VACNF) array with unique conically stacked graphitic structure directly grown on a planar Cu current collector (denoted as VACNF/Cu) is used as a high‐porosity 3D host to overcome the commonly encountered issues of Li metal anodes. The excellent electrical conductivity and highly active lithiophilic graphitic edge sites facilitate homogenous coaxial Li plating/stripping around each VACNF and forming a uniform solid electrolyte interphase. The high specific surface area effectively reduces the local current density and suppresses dendrite growth during the charging/discharging processes. Meanwhile, this open nanoscale vertical 3D structure eliminates the volume changes during Li plating/stripping. As a result, highly reversible Li plating/stripping with high coulombic efficiency is achieved at various current densities. A low voltage hysteresis of 35 mV over 500 h in symmetric cells is achieved at 1 mA cm−2with an areal Li plating capacity of 2 mAh cm−2, which is far superior to the planar Cu current collector. Furthermore, a Li–S battery using a S@PAN cathode and a lithium‐plated VACNF/Cu (VACNF/Cu@Li) anode with slightly higher capacity (2 mAh cm−2) exhibits an excellent rate capability and high cycling stability with no capacity fading over 600 cycles.
more » « less- PAR ID:
- 10459665
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 30
- Issue:
- 4
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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