Interface-Optimized Sn₄P₃/CMK-3 Nanocomposite for Stable Lithium-Ion Storage

Sn 4 P 3 has been recognized as a promising candidate for an anode material for lithium-ion batteries (LIBs) because of its appropriate operating potential and high theoretical capacity. Unfortunately, the rapid fading of capacity induced by volume change, low electrical conductivity, and limited lithium-ion charging speed hindered the actual application of Sn 4 P 3 . Building physical barriers of carbon-based material on the surface of Sn 4 P 3 particles is a common way to handle the above issues. In our work, Sn 4 P 3 particles were confined in an ordered mesoporous carbon framework (CMK-3) via a low-pressure vapor method. CMK-3 can not only improve the electric conductivity but also buffer the volume effect by using its mesopore channels to provide accommodation for the huge volume expansion of Sn 4 P 3 particles. In addition, Sn 4 P 3 nanoparticles were synthesized in CMK-3 frameworks via a low-pressure vapor method to obtain the Sn 4 P 3 /CMK-3 nanocomposite. The nanosize effect can shorten electron transfer distance, leading to faster reaction kinetics to improve electrochemical performance. The Sn 4 P 3 /CMK-3 was further grafted by a thin layer of poly(3,4-ethylenedioxythiophene) (PEDOT) to prevent the continuing buildup of poorly conducting species and thus optimize the solid electrolyte interface, which has been evidenced by in-depth X-ray photoelectron spectroscopy via Ar cluster etching. As a result of the dual-confining strategy, Sn 4 P 3 /CMK-3@PEDOT showed relatively high rate performance (reversible capacity of 438 mAh g –1 at 2.0 A g –1 ) and stable cycling performance (923 mAh g –1 at 0.5 A g –1 over 740 cycles).