fig6

Figure 6. (A) Illustration of the synthesis of AMO. Reprinted with permission^[106]. Copyright 2023, John Wiley and Sons; (B) The preparation procedure for δ-MnO₂ with rich oxygen vacancies (δ-MnO_2-x). Reprinted with permission^[109]. Copyright 2023, Elsevier; (C) PVP intercalation in δ-MnO₂. Reprinted with permission^[108]. Copyright 2023, John Wiley and Sons; (D) Ti₃C₂ MXene nanosheets with good conductivity enable fast electron transfer kinetics. Reprinted with permission^[109]. Copyright 2023, Elsevier; (E) The advantages of δ-MnO₂-C NA structure. Reprinted with permission^[110]. Copyright 2023, John Wiley and Sons; (F) The synthesis process for a-MnBO_x. Reprinted with permission^[111]. Copyright 2023, John Wiley and Sons. PVP: Polyvinylpyrrolidone; AMO: ammonium ions doped manganese dioxide.