Three-dimensional pie-like current collectors for dendrite-free lithium metal anodes

Lithium (Li) metal possesses very high specific capacity and low electrochemical potential, which shows great advantages to be used in next generation rechargeable Li metal batteries (LMBs). However, poor cyclability of Li metal anodes caused by inhomogeneous and uncontrolled Li deposition hinders the practical applications of rechargeable LMBs. Here, in order to effectively suppress Li dendrite growth without degrading the specific capacity, a three-dimensional (3D) pie-like porous current collector was prepared based on copper nanowires (CuNWs) and graphene (GE). The inter-spaces inside the CuNWs framework efficiently accommodate Li deposition. Meanwhile, the GE layer wrapped outside CuNWs functions as flexible interfacial protective layer that could protect extra Li deposition. Furthermore, the GE shell can also decelerate the oxidation of CuNWs in ambient atmosphere. The CuNWs@GE current collectors demonstrated several merits to achieve better Li metal anodes with significantly improved Coulombic efficiency and cyclability for rechargeable LMBs.