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 Bi 2 O 3 @C and BiOCl@C anodes are architected via a two-for-one manner. Specifically, optimal Bi 2 O 3 @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 Bi 2 O 2 CO 3 also contributes to the outstanding stability. Our work provides rational guidance for architecting high capacitive and ultrastable anodes for aqueous rechargeable alkaline battery.