Self-templating thermolysis synthesis of Cu_2–xS@M (M = C, TiO₂, MoS₂) hollow spheres and their application in rechargeable lithium batteries

Owing to their unique structural stability and impressive long-term cycling performance, coated hollow structures are highly attractive for energy storage systems, especially batteries. Many efforts have been devoted and various strategies have been proposed to prepare such materials. In the present work, we propose a self-templating thermolysis strategy, different from traditional wet processing methods, to fabricate cuprous sulfide hollow spheres coated with different shells, by exploiting the thermal decomposition properties of the core (CuS) and the protection provided by the shell. To demonstrate the generality of this synthetic approach, three different coating materials (carbon, TiO₂, MoS₂) have been chosen to prepare Cu_2–xS@C, Cu_2–xS@TiO₂ and Cu_2–xS@MoS₂ hollow spheres. All synthesized composite materials were then assembled as electrodes and tested in lithium batteries, showing excellent cycling stability. In particular, the electrochemical properties of Cu_2–xS@C were thoroughly investigated. The results of this work provide an alternative route to prepare coated metal sulfide hollow spheres for energy storage applications.