Influence of Process Parameters on the Electrochemical Properties of Hierarchically Structured Na₃V₂(PO₄)₃/C Composites

Sodium vanadium phosphate Na3V2(PO4)3 (NVP) is a promising next-generation cathode material for sodium-ion batteries (SIB) but the practical application as a cathode active material for SIBs is hindered by its poor electronic conductivity. To overcome this limitation and to improve the electrochemical performance in terms of rate capability and cycling stability, carbon coatings are a viable approach. In this work, we utilized a spray-drying synthesis process and systematically varied the processing parameters to optimize the electrochemical performance of NVP/carbon composite materials. The spray-drying process yields spherical, porous granules of NVP particles embedded in a carbon matrix, which is formed by the thermal decomposition of polyacrylic acid or β-lactose

Prospective Sustainability Screening of Sodium-Ion Battery Cathode Materials

Sodium-ion batteries (SIB) are considered as a promising alternative to overcome existing sustainability challenges related to Lithium-ion batteries (LIB), such as the use of critical and expensive materials with high environmental impacts. In contrast to established LIBs, SIBs are an emerging technology in an early stage of development where a challenge is to identify the most promising and sustainable cathode active materials (CAM) for further research and potential commercialization. Thus, a comprehensive and flexible CAM screening method is developed, providing a fast and comprehensive overview of potential sustainability hotspots for supporting cathode material selection. 42 different SIB cathodes are screened and benchmarked against eight state-of-the-art LIB-cathodes. Potential impacts are quantified for the following categories: i) Cost as ten-year average; ii) Criticality, based on existing raw material criticality indicators, and iii) the life cycle carbon footprint. The results reveal that energy density is one of the most important factors in all three categories, determining the overall material demand. Most SIB CAM shows a very promising performance, obtaining better results than the LIB benchmark. Especially the Prussian Blue derivatives and the manganese-based layered oxides seem to be interesting candidates under the given prospective screening framework

Prospective Sustainability Screening of Sodium-Ion Battery Cathode Materials

Sodium-ion batteries (SIB) are considered as a promising alternative to overcome existing sustainability challenges related to Lithium-ion batteries (LIB), such as the use of critical and expensive materials with high environmental impacts. In contrast to established LIBs, SIBs are an emerging technology in an early stage of development where a challenge is to identify the most promising and sustainable cathode active materials (CAM) for further research and potential commercialization. Thus, a comprehensive and flexible CAM screening method is developed, providing a fast and comprehensive overview of potential sustainability hotspots for supporting cathode material selection. 42 different SIB cathodes are screened and benchmarked against eight state-of-the-art LIB-cathodes. Potential impacts are quantified for the following categories: i) Cost as ten-year average; ii) Criticality, based on existing raw material criticality indicators, and iii) the life cycle carbon footprint. The results reveal that energy density is one of the most important factors in all three categories, determining the overall material demand. Most SIB CAM shows a very promising performance, obtaining better results than the LIB benchmark. Especially the Prussian Blue derivatives and the manganese-based layered oxides seem to be interesting candidates under the given prospective screening framework

Enabling Long‐term Cycling Stability of Na₃V₂(PO₄)₃ /C vs . Hard Carbon Full‐cells

Sodium-ion batteries are becoming an increasingly important complement to lithium-ion batteries. However, while extensive knowledge on the preparation of Li-ion batteries with excellent cycling behavior exists, studies on applicable long-lasting sodium-ion batteries are still limited. Therefore, this study focuses on the cycling stability of batteries composed of Na3V2(PO4)3/C based cathodes and hard carbon anodes. It is shown that full-cells with a decent stability are obtained for ethylene carbonate/propylene carbonate electrolyte and the conducting salt NaPF6. With cathode loadings of 1.2 mAh/cm2, after cell formation discharge capacities up to 92.6 mAh/g are obtained, and capacity retentions >90 % over 1000 charge/discharge cycles at 0.5 C/0.5 C are observed. It is shown that both, the additive fluoroethylene carbonate and impurities in the electrolyte, negatively affect the overall discharge capacity and cycling stability and should therefore be avoided. Remarkably, the internal resistances of well-balanced and well-built cells did not increase over 1500 cycles and 5 months of testing, which is a very promising result regarding the possible lifespan of the cells. The initial loss of active sodium ions in hard carbon remains a major problem, which can only be partially reduced by proper balancing

Enabling Long-term Cycling Stability of Na3V2(PO4)3/C vs. Hard Carbon Full-cells

Sodium-ion batteries are becoming an increasingly important complement to lithium-ion batteries. However, while extensive knowledge on the preparation of Li-ion batteries with excellent cycling behavior exists, studies on applicable long-lasting sodium-ion batteries are still limited. Therefore, this study focuses on the cycling stability of batteries composed of Na3V2(PO4)3/C based cathodes and hard carbon anodes. It is shown that full cells with a decent stability are obtained for ethylene carbonate / propylene carbonate electrolyte and the conducting salt NaPF6. With cathode loadings of 1.2 mAh/cm², after cell formation discharge capacities up to 92.6 mAh/g are obtained, and capacity retentions > 90 % over 1000 charge / discharge cycles at 0.5 C / 0.5 C are observed. It is shown that both, the additive fluoroethylene carbonate and traces of water in the cell, negatively affect the overall discharge capacity and cycling stability and should therefore be avoided. Remarkably, the internal resistances of well-balanced and wellbuilt cells did not increase over 1500 cycles and 5 months of testing, which is a very promising result regarding the possible lifespan of the cells. The initial loss of active sodium in hard carbon remains a major problem, which can only be partially reduced by proper balancing