Monolithic three‐dimensional hollow nanoporous Cu_xO encapsulated mesoporous Cu heterostructures with superior Li storage properties

Abstract Drastic volume expansion and low conductivity are critical factors leading to severe capacity decay of transition metal oxides (TMOs) as anodes for lithium‐ion batteries (LIBs). An effective strategy to overcome this challenge is to engineer freestanding 3D hollow architectures integrated with nanostructured metals to boost their structural stability and electrical conductivity simultaneously. Inspired by cowpea configuration beneficial to improve the transport of rich water in arid environment, herein, a novel monolithic 3D hollow nanoporous Cu_xO encapsulated mesoporous Cu heterostructure (3D‐HNP Cu_xO@m‐Cu) is delicately designed and fabricated via a simple three‐step approach. Compared to other Cu_xO‐based electrodes with different structure designs in published reports, the unique 3D‐HNP Cu_xO@m‐Cu as a binder‐free integrated anode for LIBs shows superior Li storage properties with first reversible capacity of 2.02 mAh cm⁻² and good cycling stability with 76.2% capacity retention and 99.9% coulombic efficiency after 200 cycles. This can be largely attributed to the unique 3D nanoporous heterostructure design with a synergistic effect between interconnected hollow Cu_xO nanotubes with bidirectional mechanical stress buffer and internal mesoporous Cu network with enhanced electrical conductivity. We believe that this work provides a brand‐new strategy for rational design and fabrication of next‐generation high‐performance TMOs‐based anodes toward advanced LIBs. image