Polar Molecule Intercalation to Weaken P2─S Bonding in MnPS3 Toward Ultrahigh‐Capacity Sodium Storage

Abstract Layered transition metal trithiophosphates ( TM PS 3 , TM = Mn, Fe, Co, etc .) with high theoretical capacity (>1 300 mAh g −1 ) are potential anode materials for sodium‐ion batteries (SIBs). However, the strong bonding between P 2 dimers and S atoms in TM PS 3 hinders the efficient alloying reaction between P 2 dimers and Na + , resulting in practical capacities much lower than theoretical values. Herein, a polar molecule diisopropylamine (DIPA) is intercalated into MnPS 3 for the first time to improve the sodium storage performance effectively. Theoretical calculations show that the electron transfer between DIPA and MnPS 3 induces more delocalized S p states and weaker P─S bonds, significantly enhancing the electrochemical activity and sodiation/desodiation reaction kinetics. Moreover, the expanded interlayer spacing from 6.48 to 10.75 Å enables faster Na + diffusion and more active sites for Na + adsorption. As expected, the DIPA‐MnPS 3 exhibits an ultrahigh capacity of 1,023 mAh g −1 at 0.2 A g −1 and excellent cycling performance (≈100% capacity retention after 4 200 cycles at 10 A g −1 ), far outperforming those metal thiophosphates anodes reported for SIBs. Interestingly, in situ and ex situ characterizations reveal a quasi‐topological intercalation mechanism of DIPA‐MnPS 3 . This work provides a novel strategy for the design of high‐performance anode materials for SIBs.