In this report, we develop a simple and effective one-step solution-phase route to in situ synthesize hollow nanoporous Cu x O microcages on 3D copper foam. When used as an anode for lithium-ion batteries, the unique 3D electrode exhibits superior Li storage properties with a first reversible capacity of 2.82 mAh cm −2 and 78.4% capacity retention after 400 cycles at 2 mA cm −2 . The excellent electrochemical performance can be ascribed to the stable hollow structure and robust nanoporous shells of Cu x O microcages, as well as in situ growth of microcages on a copper foam substrate with a 3D porous architecture, which is greatly beneficial to buffer large volume changes, increase the loading mass of active material, and boost the binding force between the active material and substrate, as well as shorten the Li + and electron migration distance.

A simple and effective one‐step strategy gives freestanding 3D dendritic hierarchical porous (DHP) Cu–Sn nanocomposites by chemically dealloying a designed Cu35Sn65 (at.%) alloy with dendritic segregation in a specific corrosive solution. A 3D DHP Cu–Sn modified by polyaniline (PANI) further makes the nanocomposites with improved conductivity and structural stability, which are typical of bimodal pore‐size distribution comprising a dendritic micron‐sized ligament‐channel structure with interconnected nanoporous channel walls. The as‐prepared 12 h dealloyed 3D DHP nanocomposites with ca. 200 μm in thickness can serve as binder‐free thick anodes for lithium‐ion batteries (LIBs) and exhibit enhanced Li storage performance with a ultrahigh first reversible capacity of 13.9 mAh cm−2 and an initial CE of 85.8%, good cycling stability with a capacity retention of 73.5% after 50 cycles, and superior rate capability with a reversible capacity of 11.95 mAh cm−2 after high‐rate cycling. These Sn‐based anodes can effectively alleviate the volume variation, enhance the loading of active materials, strengthen the stability of solid electrolyte interphase films, shorten the Li+ migration distance, and improve the electron conductivity. Additionally, the Sn content and areal capacity of the 3D DHP electrode can be tuned by changing the dealloying time of the initial alloy for 3D tin‐based thick anodes with adjustable capacities toward high‐performance LIBs.

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