Prussian blue analogues‐derived nitrogen‐doped carbon‐coated FeO/CoO hollow nanocages as a high‐performance anode material for Li storage

Abstract The design of electrode materials with specific structures is considered a promising approach for improving the performance of lithium‐ion batteries (LIBs). In this paper, FeO/CoO hollow nanocages coated with a N‐doped carbon layer (FCO@NC) was prepared using Fe‐Co‐based Prussian blue analogs (PBA) as a precursor. During the synthesis, dopamine was the carbon and nitrogen source. The reducing atmosphere was assured via NH 3 /Ar, which regulated the vacancies in the structure of FCO@NC as well as increased its conductivity. When used as anode materials for LIBs, the FCO@NC nanocages deliver a high reversible capacity of 774.89 mAh·g −1 at 0.3 A·g −1 after 200 cycles with a capacity retention rate of 80.4% and 426.76 mAh·g −1 after 500 cycles at a high current density of 1 A·g −1 . It is demonstrated that the hollow nanocage structure can effectively enhance the cycle stability, and the heat treatment in NH 3 /Ar atmosphere contributes to the oxygen vacancy content of the electrode materials, further facilitating its conductivity and electrochemical performance.