A Peapod‐like CoP@C Nanostructure from Phosphorization in a Low‐Temperature Molten Salt for High‐Performance Lithium‐Ion Batteries

A mild phosphorization process in low‐temperature molten salt (NaCl‐KCl‐AlCl 3 ) has been developed to synthesize peapod‐like CoP@C nanostructures by using low‐toxicity industrial PCl 3 as the phosphorus source and Mg as the reductant at 250 °C. Importantly, high efficiency of the phosphorous source is achieved since only stoichiometric PCl 3 is required to complete the reaction. The molten NaCl‐KCl‐AlCl 3 not only provides a liquid environment but also participates in the electron transport by the reversible conversion of the Al 3+ /Al redox couple. The obtained 0D‐in‐1D peapod CoP@C structure exhibits excellent lithium storage performance, delivering a superiorly stable capacity of 500 mAh g −1 after 800 cycles at a high current of 1.0 A g −1 .