Metamorphosis-Like Growth of Fexmn1-Xpx3 (X=S, Se) Hexagonal Sheets on Carbon Nanotubes Network for High-Performance Potassium Ion Batteries

The exploration of advanced electrode materials through rational structure/ morphology design is the key to develop high-performance rechargeable batteries. Herein, a controllable bionic growth of metal phosphorus trichalcogenides (MPX 3 , X=S, Se) breaking through nitrogen-doped carbon nanotubes (NCNT) is developed. Through one-step phosphorization-sulfurization/selenization, the encapsulated metal carbide nanoparticles can transfer into MPX 3 hexagonal platelets bursting from NCNT. The in situ growth of MPX 3 on NCNT can decrease K + diffusion resistance and buffer the volumetric change during cycles. Besides, theoretical calculations suggest that the decreased adsorption energy of K + in Mn-doped FePSe 3 (Fe x Mn 1-x PSe 3 ) roots in the asymmetric binding character between K and Se. Consequently, the optimized Fe x Mn 1-x PSe 3 nanosheets, which are tightly attached to NCNT as anode for potassium-ion batteries (PIBs), can exhibit a superior capacity performance of 122 mA h g -1 at 1.0 A g -1 for 1000 cycles. This work gives insight into the design and synthesis of two-dimensional van der Waals crystals as superior anodes for PIBs.