Self-Standing 3D Hollow Nanoporous SnO₂-Modified Cu_xO Nanotubes with Nanolamellar Metallic Cu Inwalls: A Facile In Situ Synthesis Protocol toward Enhanced Li Storage Properties

SnO₂ is regarded as a prospective anode material candidate for high energy density lithium-ion batteries (LIBs). However, rapid structural degradation and low conductivity always bring about poor cycling stability and electrochemical reversibility, becoming critical dilemmas toward its practical application. To address these issues, herein, a facile multi-step in situ synthesis protocol is developed to tactfully achieve self-standing 3D hollow nanoporous SnO₂-modified Cu_xO nanotubes with nanolamellar metallic Cu inwalls (3D-HNP SnO₂/Cu_xO@n-Cu) via chemical dealloying, heat treatment, electrochemical replacement, and selective etching. The results show that the unique 3D-HNP SnO₂/Cu_xO@n-Cu as a binder-free integrated anode for LIBs exhibits superior Li storage properties with high initial reversible capacity of 3.34 mAh cm⁻² and good cycling stability with 85.6% capacity retention and >99.4% coulombic efficiency after 200 cycles (capacity decay of only 0.002 mAh cm⁻² per cycle). This is mainly attributed to the unique 3D hollow nanoporous configuration design composed of interlinked Cu_xO nanotubes modified by ultrafine SnO₂ nanocrystals (4–10 nm) with two-way mechanical strain cushion and nanolamellar metallic Cu inwalls with boosted electrical conductivity. This work can be expected to offer an original and effective approach for rational design and fabrication of advanced MOx-based anodes toward high-performance LIBs.