In Situ Structural Self-Optimization and Oxygen Vacancy Creation to Boost the Stability of Bi-MOF Derived Bi2O3@C and BiOCl@C Anodes

Metal oxides are promising alkaline battery electrodes with high theoretical capacity, but the low energy density and poor stability make them far away from actual application. Herein, single Bi-MOF derived ultrastable Bi2O3@C and BiOCl@C anodes are architected via a two-for-one manner. Specifically, optimal Bi2O3@C anode with hierarchical and porous structure delivers high specific capacity (278.3 mAh g–1 at 1 A g–1) owing to the exposed electrochemical active sites, fast charge transfer, and efficient ion diffusion. More importantly, ultrahigh stability (110%, 5000 cycles) is achieved due to the in situ morphological self-optimization and oxygen vacancy creation. Similarly, BiOCl@C anode also displays remarkable capacity and ultralong cycling stability (94%, 15000 cycles) due to the conductive and protective carbon layer, abundant reactive centers, and ion transport channels. Moreover, the in situ phase transition of BiOCl to Bi2O2CO3 also contributes to the outstanding stability. Our work provides rational guidance for architecting high capacitive and ultrastable anodes for aqueous rechargeable alkaline battery.