Sodium insertion in high pressure β-V2O5 : a new high capacity cathode material for sodium ion batteries
| Autor: | Alois Kuhn, Flaviano García-Alvarado, Emilio Morán, Rafael Córdoba, Juan Carlos Pérez-Flores, J.M. Gallardo-Amores |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Reaction mechanism
Materials science Sodium Analytical chemistry Energy Engineering and Power Technology chemistry.chemical_element Sodium insertion 02 engineering and technology 010402 general chemistry Electrochemistry 01 natural sciences Ion law.invention law Formula unit Specific energy Ex situ XRD Electrical and Electronic Engineering Physical and Theoretical Chemistry Renewable Energy Sustainability and the Environment 021001 nanoscience & nanotechnology Cathode 0104 chemical sciences Vanadium oxide chemistry Battery material 0210 nano-technology Current density |
| Popis: | β-V2O5, obtained by a high-temperature high-pressure method, exhibits a layered structure that favours the insertion of Na+. In this work, we report the electrochemical insertion of sodium in high pressure β-V2O5 and its performance as cathode material for sodium-ion batteries. The material shows a first discharge capacity of 132 mAh g−1 in the 3.6–2.0 V range at a C/20 current density and a maximum capacity of 147 mAh g−1 under equilibrium conditions, corresponding to the insertion of 1 Na+ ion per formula unit. The β-V2O5//Na cell delivers a specific energy as high as 370–410 Wh kg−1. The amount of inserted sodium points to the reduction of 50% of the available V5+ ions. After 20 cycles, the discharge capacity retains 86% of the initial capacity. Concerning the reaction mechanism of high pressure β-V2O5 upon sodium insertion/de-insertion, several phase transitions are inferred from the voltage-composition profile. Ex situ XRD reveals the appearance of several NaxV2O5 phases in the 0 ≤ x ≤ 1 compositional range, which are closely related with the non-sodiated high pressure β-V2O5 structure. An irreversible structural transformation occurs during the very first inserted sodium, at the beginning of the first discharge, and the original high pressure β-V2O5 structure is not recovered upon full Na+ extraction. Electrochemical performances are outstanding though. |
| Databáze: | OpenAIRE |
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