Fig. 7: Cycling stability of N-HP-Co SACs.

a N 1s XPS spectra for N-HP-Co SACs after 50 galvanostatic cycles. b HAADF-STEM images and the corresponding EDX elemental maps after 50 galvanostatic cycles, 200 nm in b. c, d XANES spectra and Fourier transform of the Co K-edge of N-HP-Co SACs, Co₃O₄, CoO, and Co foil.