The yolk-shell FeSe@C nanobox with novel synthesis and its high performance for the anode of lithium-ion batteries

Abstract

Iron selenide (FeSe) is a promising anode material for lithium-ion batteries (LIBs), with high specific capacity, high tap-density and good electrical conductivity. However, the rapid decay of specific capacity seriously impedes its practical application, which results from the large volume change during charge-discharge cycles damaging electrode structure. Here, the yolk-shell FeSe@C nanobox is successfully synthesized via a novel method of selenization to the core after carbonization to the shell with chemical vapor deposition (CVD). The space between the core and the shell helps to release the volume expansion during lithiation/delithiation processes, and FeSe is kept inside the carbon microboxes without breaking the shell. Therefore, the yolk-shell FeSe@C displays outstanding electrochemical performance as the anode of lithium-ion batteries, which remained a specific capacity of 871.6 mAh g−1 after 250 cycles at a current density of 1 A g−1 and at a large current density, 10 A g−1, the specific capacity can still reach 430.4 mA h g−1. This novel yolk-shell structure and the synthesis strategy could be employed in other anode materials for high-performance lithium-ion batteries and other electrochemical devices.