Facile citrate gel synthesis of an antimony–carbon nanosponge with enhanced lithium storage

Abstract

In this study, we introduce a facile and simple synthesis of Sb@C nanosponges by a citrate sol–gel method, accompanied by conventional carbonization in an inert gas. The synthesized Sb@C nanosponges are comprised of Sb nanoparticles encapsulated by a carbon shell, interconnected to form a highly porous three-dimensional structure. The carbon content in the Sb@C composites is controllable by changing the ratio between the carbon source and the Sb-containing precursor. The resulting sponge-like Sb@C nanocomposites show promising potential as an anode active material for lithium-ion batteries with excellent electrochemical performance involving the specific discharge capacity and rate capability. The optimized Sb@C nanocomposite has a high reversible capacity of 634.4 mA h g⁻¹ with a miniscule capacity loss of 0.0349% per cycle after 100 cycles at a discharge–charge rate of 0.1C. Moreover, even at a remarkably high current rate of 10C, the electrode delivers an impressive reversible capacity of 405.97 mA h g⁻¹. The enhanced properties of the Sb@C nanocomposite, including remarkable lithium storage and outstanding cycling stability, are likely ascribed to the synergetic effect of its three-dimensional nano-architecture of interconnected Sb nanoparticles, which generates sufficient internal void space to accommodate the volume expansion of Sb in the alloying process, and the inclusion of the carbon buffer layer on the Sb nanoparticles.