3D soft lithiophilic current collector of Ag-CuNW/MWCNT@melamine foam enables dendrite-free lithium metal anodes

Abstract

Li metal is one of the most promising anode materials for next-generation batteries due to its extremely low electrochemical potential and superior theoretical capacity. However, uncontrollable dendrite growth and severe volume expansion result in serious issues such as low coulombic efficiency and short cycle life, which limit its applications. Herein, a Cu nanowire (CuNW) and a multi-walled carbon nanotube (MWCNT) were closely loaded on a melamine foam (MF) to construct a conductive composite, and then Ag nanoparticles were grown in situ on the CuNW surface via a replacement reaction to form a 3D soft lithiophilic current collector of Ag-CuNW/MWCNT@MF for achieving dendrite-free anodes. The tightly interconnected CuNW/MWCNT composite network with excellent conductivity can significantly reduce the current density, while the soft MF with a special porous structure can effectively buffer the internal extrusion stress generated during Li anode cycling, thereby suppressing the dendrite growth and “dead Li” formation. The lithiophilic Ag nanoparticles on the CuNW can reduce the overpotential for Li deposition and act as nucleation sites, directing uniform Li distribution. This 3D soft lithiophilic current collector exhibits a large Li capacity, with no obvious dendrites after the deposition of 90 mA h cm⁻² of Li, and can be stably cycled for 2000 h at 1 mA cm⁻²/1 mA h cm⁻², with an ultra-low nucleation overpotential of only 6 mV.