Gas-phase Kirkendall effect inducing built-in bifunctional ultrafine Cu nanocrystalline integrated 3D hollow nanoporous CuxO anode towards excellent lithium storage performance

Traditional CuxO (x = 1, 2) electrodes exhibit excellent specific capacity, but the poor stress-buffering performance and inferior conductivity hinder its further application. To solve these issues, herein, we develop a built-in bifunctional ultrafine Cu nanocrystalline networks hybridized 3D hollow nanoporous CuxO (BUCN@3D-HN CuxO) integrated anode by a facile gas-phase Kirkendall effect. The 3D hollow nanoporous (3D-HN) structure can bidirectionally retard the change of stress, while the built-in ultrafine Cu nanocrystalline networks (BUCN) own the effect of providing rapid internal electron transport across the active/inert Cu/CuxO system. Benefiting from the synergistic effect of the excellent stress-buffering ability and improved electronic conductivity, the designed BUCN@3D-HN CuxO electrode delivers a high initial reversible capacity of 1.67 mAh cm−2 under the current density of 1 mA cm−2. Besides, a high capacity retention of 0.96 mAh cm−2 with a high capacity retention ratio of 85.7 % is achieved even after 800 cycles at a high rate of 4 mA cm−2. This work provides a facile yet effective method to prepare hollow nanoporous electrodes and emphasizes the significance of active/inert system, which may shed light on the design of other high-performance electrodes beyond Lithium-ion batteries. A built-in bifunctional ultrafine Cu nanocrystalline integrated 3D hollow nanoporous CuxO (BUCN@3D-HN CuxO) anode was prepared using the gas-phase Kirkendall effect, which enabled the anode to exhibit high areal specific capacity of 1.67 mAh cm−2 at 1 mA cm−2 and a capacity retention ratio of 84.43 % after 100 cycles. [Display omitted] •The BUCN@3D-HN CuxO is synthesized by gas-phase Kirkendall effect.•Excellent stress-buffering ability and electronic conductivity are achieved.•The self-supported electrode has excellent specific capacity and cycling stability.