摘要
Practical applications of conversion-type metal selenide electrodes in potassium ion batteries (PIBs) encounter multiple challenges, such as particle aggregation, the shuttle effect, and pulverization during cycling. We design a Janus heterostructure, namely CoSe 2 -FeSe 2 /graphite/N-doped carbon (CFS//g@NC), with dual heterojunctions (p-n and Schottky junction), which generates the synergistic effect to enhance interface charge storage and improve electrode structure integrity. When the Janus heterostructure is used as a PIB anode, it demonstrates high-rate performance up to 10 A/g, offering a capacity of 200 mA h g −1 and excellent cycling stability of over 2500 cycles at 0.5 A/g. According to the density functional theory (DFT) calculations, the diffusion barrier of K ions on CFS//g@NC is two times lower than that on CoSe 2 or FeSe 2 . The distribution of n-type and p-type semiconductors in the Janus particles has been confirmed by quantitative assessment through dark-field electron microscopy. In addition to the p-n junction crossing two semiconductor interfaces, the Schottky junction between the graphite layer derived from Prussian blue analogues (PBA) and the semiconductor also creates a built-in electric field, thus enhancing ion/electron transport and increasing the diffusion of potassium ions. This work provides new insights into the architectural strategy of multi-layer heterointerfaces and offers a promising new pathway for anode design in PIBs.