Affiliation:
1. Electrochemical Energy Storage Laboratory Department of Chemistry SRM Institute of Science and Technology Tamil Nadu 603203 India
2. Department of Materials Science and Nano Engineering Rice University Houston Texas 77005 USA
3. Center for Human and Natural Sciences (CCNH) Federal University of ABC (UFABC) Avenida dos Estados 5000, Santo André São Paulo Brazil
4. Nanomaterials for Energy Storage and Conversion INL International Iberian Nanotechnology Laboratory Av. Mestre José Veiga Braga 4715‐330 Portugal
Abstract
AbstractTransition metal derivatives exhibit high theoretical capacity, making them promising anode materials for sodium‐ion batteries. Sulfides, known for their superior electrical conductivity compared to oxides, enhance charge transfer, leading to improved electrochemical performance. Here, a hierarchical WS2 micro‐flower is synthesized by thermal sulfurization of WO3. Comprising interconnected thin nanosheets, this structure offers increased surface area, facilitating extensive internal surfaces for electrochemical redox reactions. The WS2 micro‐flower demonstrates a specific capacity of ≈334 mAh g−1 at 15 mA g−1, nearly three times higher than its oxide counterpart. Further, it shows very stable performance as a high‐temperature (65 °C) anode with ≈180 mAh g−1 reversible capacity at 100 mA g−1 current rate. Post‐cycling analysis confirms unchanged morphology, highlighting the structural stability and robustness of WS2. DFT calculations show that the electronic bandgap in both WS2 and WO3 increases when going from the bulk to monolayers. Na adsorption calculations show that Na atoms bind strongly in WO3 with a higher energy diffusion barrier when compared to WS2, corroborating the experimental findings. This study presents a significant insight into electrode material selection for sodium‐ion storage applications.