Illustrating the influence of anodic/cathodic second-phases on dissolution mode via Mg–Ca–Sn alloy anodes for primary Mg-air cells

Two second-phases with an opposite potential difference to the α-Mg matrix may affect the discharge mechanism of magnesium (Mg) anodes for primary Mg-air cells through different micro-galvanic behaviors. Herein, using Mg–Ca-xSn alloys anode with Mg2Ca and CaMgSn phases, we investigated their influen...

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Main Authors: Bowen Yu, Haitao Jiang
Format: Article
Language:English
Published: Elsevier 2024-11-01
Series:Journal of Materials Research and Technology
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Online Access:http://www.sciencedirect.com/science/article/pii/S2238785424024876
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author Bowen Yu
Haitao Jiang
author_facet Bowen Yu
Haitao Jiang
author_sort Bowen Yu
collection DOAJ
description Two second-phases with an opposite potential difference to the α-Mg matrix may affect the discharge mechanism of magnesium (Mg) anodes for primary Mg-air cells through different micro-galvanic behaviors. Herein, using Mg–Ca-xSn alloys anode with Mg2Ca and CaMgSn phases, we investigated their influence on the dissolution mode of Mg-anode during discharge state via in-situ scanning vibrating electrode technique (SVET) technology. Firstly, the peak surface positive potential of Mg–1Ca alloy only containing Mg2Ca phase and Mg–1Ca–1Sn alloy with CaMgSn/Mg2Ca phase increases multiplied by 10 during the discharge process compared to that of OCP, exhibiting accelerated anodic substrate dissolution. Moreover, Mg2Ca-phases can be attacked firstly while promoting the discharge of the α-Mg matrix surrounding them, leading to the preferential dissolution of grain boundaries and “chunk effects (CE)” occurrence. More CaMgSn/α-Mg couples are activated to form dispersed micro-galvanic cell islands, which also boosts the dissolution of the α-Mg matrix but reduces the area of high-intensity dissolution reaction due to CaMgSn acting as a cathode. However, excessive CaMgSn-phase generally fails to discharge effectively to reduce anode efficiency, although it can improve the self-peeling capacity of the film layer through physical detachment; in addition, with Sn content increasing to 3 wt%, the open circuit voltage of Mg–1Ca–3Sn significantly declines. Mg–1Ca-0.2Sn exhibits the highest cell voltage and anodic efficiency by introducing a tiny amount of dispersed short rod-like CaMgSn, due to the adjusted dissolution mode, enhanced electrochemical activity and inhibited CE. Finally, our study provides a universal mechanism for fabricating Mg-anode with high performance via phase composition modulation.
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spelling doaj-art-a1df801e0672469d9c1f3a903a0226df2024-12-26T08:55:01ZengElsevierJournal of Materials Research and Technology2238-78542024-11-013361026113Illustrating the influence of anodic/cathodic second-phases on dissolution mode via Mg–Ca–Sn alloy anodes for primary Mg-air cellsBowen Yu0Haitao Jiang1Institute of Engineering Technology, University of Science and Technology Beijing, Beijing, 100083, ChinaCorresponding author.; Institute of Engineering Technology, University of Science and Technology Beijing, Beijing, 100083, ChinaTwo second-phases with an opposite potential difference to the α-Mg matrix may affect the discharge mechanism of magnesium (Mg) anodes for primary Mg-air cells through different micro-galvanic behaviors. Herein, using Mg–Ca-xSn alloys anode with Mg2Ca and CaMgSn phases, we investigated their influence on the dissolution mode of Mg-anode during discharge state via in-situ scanning vibrating electrode technique (SVET) technology. Firstly, the peak surface positive potential of Mg–1Ca alloy only containing Mg2Ca phase and Mg–1Ca–1Sn alloy with CaMgSn/Mg2Ca phase increases multiplied by 10 during the discharge process compared to that of OCP, exhibiting accelerated anodic substrate dissolution. Moreover, Mg2Ca-phases can be attacked firstly while promoting the discharge of the α-Mg matrix surrounding them, leading to the preferential dissolution of grain boundaries and “chunk effects (CE)” occurrence. More CaMgSn/α-Mg couples are activated to form dispersed micro-galvanic cell islands, which also boosts the dissolution of the α-Mg matrix but reduces the area of high-intensity dissolution reaction due to CaMgSn acting as a cathode. However, excessive CaMgSn-phase generally fails to discharge effectively to reduce anode efficiency, although it can improve the self-peeling capacity of the film layer through physical detachment; in addition, with Sn content increasing to 3 wt%, the open circuit voltage of Mg–1Ca–3Sn significantly declines. Mg–1Ca-0.2Sn exhibits the highest cell voltage and anodic efficiency by introducing a tiny amount of dispersed short rod-like CaMgSn, due to the adjusted dissolution mode, enhanced electrochemical activity and inhibited CE. Finally, our study provides a universal mechanism for fabricating Mg-anode with high performance via phase composition modulation.http://www.sciencedirect.com/science/article/pii/S2238785424024876Mg-air cell anodesSecond-phasesMicro-galvanic couplesIn-situ SVETDissolution modes
spellingShingle Bowen Yu
Haitao Jiang
Illustrating the influence of anodic/cathodic second-phases on dissolution mode via Mg–Ca–Sn alloy anodes for primary Mg-air cells
Journal of Materials Research and Technology
Mg-air cell anodes
Second-phases
Micro-galvanic couples
In-situ SVET
Dissolution modes
title Illustrating the influence of anodic/cathodic second-phases on dissolution mode via Mg–Ca–Sn alloy anodes for primary Mg-air cells
title_full Illustrating the influence of anodic/cathodic second-phases on dissolution mode via Mg–Ca–Sn alloy anodes for primary Mg-air cells
title_fullStr Illustrating the influence of anodic/cathodic second-phases on dissolution mode via Mg–Ca–Sn alloy anodes for primary Mg-air cells
title_full_unstemmed Illustrating the influence of anodic/cathodic second-phases on dissolution mode via Mg–Ca–Sn alloy anodes for primary Mg-air cells
title_short Illustrating the influence of anodic/cathodic second-phases on dissolution mode via Mg–Ca–Sn alloy anodes for primary Mg-air cells
title_sort illustrating the influence of anodic cathodic second phases on dissolution mode via mg ca sn alloy anodes for primary mg air cells
topic Mg-air cell anodes
Second-phases
Micro-galvanic couples
In-situ SVET
Dissolution modes
url http://www.sciencedirect.com/science/article/pii/S2238785424024876
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