A Selective Reduction Approach to Construct Robust Cu_1.81S Truss Structures for High-Performance Sodium Storage

The practical application of transition metal sulfides as anodes for sodium-ion batteries has long been hindered by the design and fabrication of stable electrodes. Here, inspired by architecture, we design a stable electrode based on Cu_1.81S micro-truss structures (MTs) for the first time. The key to this “selective reduction” strategy is to engrave Cu_1.75S precursors with a truss structure by using an anti-reduction agent (Fe³⁺ ions), and a subsequent recrystallization process reinforces the truss structure. The Cu_1.81S MTs with high structural stability exhibits a pronounced stability enhancement for 1,000 cycles with 77.7% capacity retention and delivers excellent rate performance of 331 mAh g⁻¹ at 3 A g⁻¹. As a new method for designing robust electrode structures, this synthetic strategy is not limited to the synthesis of truss structures. It provides new insights into a new generation of electrode structures and could be applied to the structural design of other batteries.