Sn Anodes Protected by Intermetallic FeSn₂ Layers for Long‐lifespan Sodium‐ion Batteries with High Initial Coulombic Efficiency of 93.8 %

Abstract

With a theoretical capacity of 847 mAh g À 1 , Sn has emerged as promising anode material for sodium-ion batteries (SIBs). However, enormous volume expansion and agglomeration of nano Sn lead to low Coulombic efficiency and poor cycling stability. Herein, an intermetallic FeSn 2 layer is designed via thermal reduction of polymer-Fe 2 O 3 coated hollow SnO 2 spheres to construct a yolk-shell structured Sn/FeSn 2 @C. The FeSn 2 layer can relieve internal stress, avoid the agglomeration of Sn to accelerate the Na + transport, and enable fast electronic conduction, which endows quick electrochemical dynamics and long-term stability. As a result, the Sn/FeSn 2 @C anode exhibits high initial Coulombic efficiency (ICE = 93.8 %) and a high reversible capacity of 409 mAh g À 1 at 1 A g À 1 after 1500 cycles, corresponding to an 80 % capacity retention. In addition, NVP//Sn/FeSn 2 @C sodium-ion full cell shows outstanding cycle stability (capacity retaining rate of 89.7 % after 200 cycles at 1 C).

Reductive Competition Effect-Derived Solid Electrolyte Interphase with Evenly Scattered Inorganics Enabling Ultrahigh Rate and Long-Life Span Sodium Metal Batteries

“…The data implies that the electrolyte is effective at a low N/P ratio and obtains a relatively high rate and power density. At last, the electrochemical performance of SMBs in this study is compared with the reported work (Figure f); remarkably, this work demonstrates exceptional rate and cycle performance. – …”

Advances in bismuth-based anodes for potassium-ion batteries

“…selecting appropriate binder), etc. 89,90,[202][203][204][205] Further efforts are needed to focus on this issue.…”

Coral-like CoSe2@N-doped carbon with a high initial coulombic efficiency as advanced anode materials for Na-ion batteries

“…This leads to a higher consumption of Na-ion in the cathode materials and electrolytes, ultimately resulting in a lower initial capacity efficiency (ICE). 20…”

“…This leads to a higher consumption of Na-ion in the cathode materials and electrolytes, ultimately resulting in a lower initial capacity efficiency (ICE). 20 As is known, the interface contact between the electrode and electrolyte can be adjusted by such surface engineering strategies as a surface coating or combining nanostructure materials with conductive materials (especially the most studied carbonaceous materials). 21,22 Carbon-coated active nanomaterials have many advantages: (a) nanostructures can significantly shorten the ion diffusion path; (b) the presence of an electron conductive carbon layer in the electrode can promote the contact between electrons and ions with the active materials; (c) the carbon layer can act as a protective barrier between the electrode and the electrolyte, reducing their direct contact and preventing side reactions.…”