Entropy‐Change Driven Highly Reversible Sodium Storage for Conversion‐Type Sulfide

Abstract

Transition metal sulfides (TMSs) are reported to be efficient sodium storage anode materials due to their rich redox chemistry and good electronic conductivity features. However, the issues of poor reaction reversibility and cyclability, caused by structure degradation and volume expansion during repeated (de)sodiation processes, have far limited the applicability of these materials. Herein, a high-entropy configuration strategy is reported for Cu 4 MnFeSnGeS 8 anodes for advanced sodium ion batteries. In this high-entropy material, the homogeneously dispersed cations can effectively suppress the continuous coarseness of Sn nanoparticles and maintain valid interface contact between M 0 and Na 2 S, thus achieving highly reversible sodium storage. Moreover, the highly reversible crystalline-phase transformation of high-entropy Cu 4 MnFeSnGeS 8 and highly inherent mechanical stability can effectively relieve the persistently accumulated mechanical stress, thus restraining continuous breakage of the solid electrolyte interphase film and pulverization of the electrode, and improving cycling stability. Furthermore, when coupled with a Na 3 V 2 (PO 4 ) 3 cathode, the full cell shows a high energy density (264 Wh kg -1 ), which makes the high-entropy-stabilized sulfide a promising anode candidate for SIBs.

Pressure‐Stabilized High‐Entropy (FeCoNiCuRu)S2 Sulfide Anode toward Simultaneously Fast and Durable Lithium/Sodium Ion Storage

“…In order to further clarify the reaction mechanism of HES, the valence changes of various metal elements after the initial fully discharge and charge of HES in LICs and SICs were investigated by ex-situ XPS (Figures S21a-e and S22a-e, Supporting Information). As expected, regardless of LICs or SICs, the metal cations in the HES are reduced to the metal 0 valence state after fully discharged to 0.01 V. [33][34][35][36][37][38][39][40] When the initial charging voltage reaches 3.0 V, the reduced Fe 0 , Co 0 , Ni 0 , Cu 0 , and Ru 0 are oxidized to Fe 2+ , Co 2+ , Ni 2+ , Cu + , and Ru 2+ , respectively, which indicates that the structure of HES has undergone a reversible structural transformation during the charge/discharge.…”

High Entropy Materials for Reversible Electrochemical Energy Storage Systems

“…Our research group recently presented a high-entropy sulfide material, Cu 4 MnFeSnGeS 8 , with a tetragonal structure, for application as a sodium-ion battery anode (Figure 4b i). [81] This material offers two key advantages: long cycling stability and a high-capacity retention rate. The first discharge capacity reached 532.7 mAh g À 1 at a current rate of 0.2 A g À 1 , at 10 A g À 1 , a capacity of 459.2 mAh g À 1 can be obtained, demonstrating remarkable rate capability in Figure 4b ii.…”

Hollow structures Prussian blue, its analogs, and their derivatives: Synthesis and electrochemical energy‐related applications

“…TMS is generally prepared by the calcination of sublimated sulfur in a tube furnace for vulcanization, or by using sulfur-containing substances, such as Na 2 S or thioacetamide (TAA), for vulcanization by hydrothermal/solvothermal reactions. [179,180] These two methods are also used when using PBAs as precursors to synthesize transition metal sulfides. [181] Yu et al [122] successfully fabricated cubic NiS nanoframes using Ni-Co PBA as template for anion exchange with S 2− in Na 2 S at high temperature (Figure 13a).…”