Highly conductive Co₃Se₄ embedded in N-doped 3D interconnected carbonaceous network for enhanced lithium and sodium storage

Traditional cobalt selenides as active materials in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) would suffer from drastic volume expansions and large stacking effects, leading to a low cycling stability. In this work, we utilized a facile template method for preparing Co₃Se₄@N-CN (CSNC) that encapsulated Co₃Se₄ nanoparticles into 3D interconnected nitrogen-doped carbon network (N-CN). Satisfactorily, it possesses excellent cycling stability with enhanced lithium and sodium energy storage capacity. As an anode material in LIBs, CSNC exhibited a prominent reversible discharge performance of 1313.5 mAh g⁻¹ after 100 cycles at 0.1 A g⁻¹ and 835.6 mAh g⁻¹ after 500 cycles at 1.0 A g⁻¹. Interestingly, according to the analysis from cyclic voltammetry, the in-situ generated Se might provide extra capacity that leaded to a rising trend of capacity. When utilized as an anode in SIBs, CSNC delivered an outstanding capacity of 448.7 mAh g⁻¹ after 100 cycles at 0.1 A g⁻¹ and could retain 328.9 mAh g⁻¹ (77.2% of that of 0.1 A g⁻¹) even at a high current density of 5.0 A g⁻¹. The results demonstrate that CSNC is a superior anode material in LIBs and SIBs with great promise. More importantly, this strategy opens up an effective avenue for the design of transition metal selenide/carbonaceous composites for advanced battery storage systems.