Co–B Nanoflakes as Multifunctional Bridges in ZnCo2O4 Micro‐/Nanospheres for Superior Lithium Storage with Boosted Kinetics and Stability

Abstract Transition metal oxides hold great promise as high‐energy anodes in next‐generation lithium‐ion batteries. However, owing to the inherent limitations of low electronic/ionic conductivities and dramatic volume change during charge/discharge, it is still challenging to fabricate practically viable compacted and thick TMO anodes with satisfactory electrochemical performance. Herein, with mesoporous cobalt–boride nanoflakes serving as multifunctional bridges in ZnCo 2 O 4 micro‐/nanospheres, a compacted ZnCo 2 O 4 /Co–B hybrid structure is constructed. Co–B nanoflakes not only bridge ZnCo 2 O 4 nanoparticles and function as anchors for ZnCo 2 O 4 micro‐/nanospheres to suppress the severe volume fluctuation, they also work as effective electron conduction bridges to promote fast electron transportation. More importantly, they serve as Li + transfer bridges to provide significantly boosted Li + diffusivity, evidenced from both experimental kinetics analysis and density functional theory calculations. The mesopores within Co–B nanoflakes help overcome the large Li + diffusion barriers across 2D interfaces. As a result, the ZnCo 2 O 4 /Co–B electrode delivers high gravimetric/volumetric/areal capacities of 995 mAh g −1 /1450 mAh cm −3 /5.10 mAh cm −2 , respectively, with robust rate capability and long‐term cyclability. The distinct interfacial design strategy provides a new direction for designing compacted conversion‐type anodes with superior lithium storage kinetics and stability for practical applications.