A vanadium-based metal–organic phosphate framework material K 2 [(VO) 2 (HPO 4 ) 2 (C 2 O 4 )] as a cathode for potassium-ion batteries

Herein, we report a layered material K2[(VO)2(HPO4)2(C2O4)] with a large interplanar lattice spacing. Highly reversible K+ extraction and insertion in the layers are achieved, with a good cycling stability of up to 200 cycles (83% of retention). And the structural evolution of this material during the electrochemical processes is explored.