Interfacial Stabilization of a Graphene-Wrapped Cu2S Anode for High-Performance Sodium-Ion Batteries via Atomic Layer Deposition

Jiyu Cai,Zonghai Chen,Xiangbo Meng

doi:10.3390/jcs4040184

Abstract

Sodium-ion batteries (SIBs) have attracted increasing attention for storing renewable clean energy, owing to their cost-effectiveness. Nonetheless, SIBs still remain significant challenges in terms of the availability of suitable anode materials with high capacities and good rate capabilities. Our previous work has developed and verified that Cu2S wrapped by nitrogen-doped graphene (i.e., Cu2S@NG composite), as an anode in SIBs, could exhibit a superior performance with ultralong cyclability and excellent rate capability, mainly due to the multifunctional roles of NG. However, the Cu2S@NG anode still suffers from continuous parasitic reactions at low potentials, causing a rapid performance deterioration. In this study, we investigated the effects of a conformal Al2O3 coating via atomic layer deposition (ALD) on the interfacial stability of the Cu2S@NG anode. As a consequence, the ALD-coated Cu2S@NG electrode can deliver a high capacity of 374 mAh g−1 at a current density of 100 mA g−1 and achieve a capacity retention of ~100% at different rates. This work verified that surface modification via ALD is a viable route for improving SIBs’ performances.

Highlights

Sodium-ion batteries (SIBs) have been highly regarded as a promising technology to constitute large stationary electrical energy storage (EES) systems for renewable clean energies, featuring their low cost and the natural abundance of sodium [1,2]
Because the parasitic reactions occurred at the low potential of ~0.13 V deteriorate the electrochemical performance of Cu2S@nitrogen-doped graphene (NG) electrode, in this work, we applied a surface coating of Al2O3 on the electrodes to achieve a stable interface and thereby suppress the parasitic reactions
The atomic layer deposition (ALD) Al2O3 coating on the electrode surface was used as a model system to demonstrate our design philosophy

Summary

Introduction

Sodium-ion batteries (SIBs) have been highly regarded as a promising technology to constitute large stationary electrical energy storage (EES) systems for renewable clean energies (e.g., solar and wind power), featuring their low cost and the natural abundance of sodium [1,2]. Due to low electron conductivity in N,S dual-doped carbon, the addition of some extra conductive agent led to a 51.5 wt% content of the active material and a low electrode capacity of 93.9 mAh g−1 (which was based on all the electrode materials, including the active material, the conductive agent, and the binder) [14] In this regard, we developed a superior Cu2S@NG composite anode for SIBs in our previous work [19]. We applied an ultrathin Al2O3 coating via ALD on Cu2S@NG electrode as a model system for investigating its effect on the interfacial stability of SIBs. Compared with the bare electrode, the ALD-coated electrode (i.e., ALD-Cu2S@NG) could enable a more stable electrochemical performance, accounting for a capacity of 374 mAh g−1 at 100 mA g−1 for 100 cycles versus a capacity of 304 mAh g−1 for the bare electrode at the same testing conditions and an exceptional capacity retention of ~100% at different current rates (up to 10 C). Our study revealed that surface modification via ALD is an important strategy to enhance interfacial stability of sodium-ion batteries for better performances

Results and Discussion

Conclusions

Experimental Section