The Li metal anode is an ideal candidate for next-generation batteries due to its ultra-high specific capacity (3860 mAh g −1) and low electrochemical potential (−3.040 V vs. standard hydrogen electrode). However, the large volume fluctuations, side reactions, and dendrite growth are serious problems that need to be solved before Li metal batteries (LMBs) can be commercialized. Herein, we develop a lithiophilic 3D Cu nanowire (3D CuNW) host that can enable molten Li infusion into the structure. Interestingly, the 3D host undergoes a structural transformation upon contact with molten Li and forms Cu-Li alloy crystallites on the surface, leading to the development of an ultra-high performance Li metal anode (3D Li@CuLi). The symmetrical cell performance of the 3D Li@CuLi electrode is found to be among the best reported for carbonate-based electrolytes and can achieve greater than 200 cycles at an ultra-high current density of 10 mA cm −2. Furthermore, full cells coupled with LiFePO4 cathodes show excellent cycling stability at a C-rate of 2 C for over 400 cycles with negligible capacity fade. This work provides a scalable and highly effective approach towards the fabrication of high performance 3D hosts with pre-stored Li metal for next-generation battery systems.