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New-concept batteries based on aqueous Li+/Na+ mixed-ion electrolytes.

Chen L, Gu Q, Zhou X, Lee S, Xia Y, Liu Z - Sci Rep (2013)

Bottom Line: Rechargeable batteries made from low-cost and abundant materials operating in safe aqueous electrolytes are attractive for large-scale energy storage.One involves Li(+) insertion/extraction reaction, and the other mainly relates to Na(+) extraction/insertion reaction.Hence, the Li(+)/Na(+) mixed-ion batteries offer promising applications in energy storage and Li(+)/Na(+) separation.

View Article: PubMed Central - PubMed

Affiliation: Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, P R China.

ABSTRACT
Rechargeable batteries made from low-cost and abundant materials operating in safe aqueous electrolytes are attractive for large-scale energy storage. Sodium-ion battery is considered as a potential alternative of current lithium-ion battery. As sodium-intercalation compounds suitable for aqueous batteries are limited, we adopt a novel concept of Li(+)/Na(+) mixed-ion electrolytes to create two batteries (LiMn2O4/Na0.22MnO2 and Na0.44MnO2/TiP2O7), which relies on two electrochemical processes. One involves Li(+) insertion/extraction reaction, and the other mainly relates to Na(+) extraction/insertion reaction. Two batteries exhibit specific energy of 17 Wh kg(-1) and 25 Wh kg(-1) based on the total weight of active electrode materials, respectively. As well, aqueous LiMn2O4/Na0.22MnO2 battery is capable of separating Li(+) and Na(+) due to its specific mechanism unlike the traditional "rocking-chair" lithium-ion batteries. Hence, the Li(+)/Na(+) mixed-ion batteries offer promising applications in energy storage and Li(+)/Na(+) separation.

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Cyclic voltammograms in different electrolytes.(a), for Na0.44MnO2 electrode at a scan rate of 0.5 mVs−1. (b), for LiMn2O4 electrode at a scan rate of 0.1 mVs−1. (c), for carbon-coated TiP2O7 electrode at a scan rate of 0.3 mVs−1. Black line: in 1 M Na2SO4; red line: in 1 M Na2SO4 + 0.125 M Li2SO4; green line: in 1 M Na2SO4 + 0.25 M Li2SO4; blue line: in 1 M Na2SO4 + 0.5 M Li2SO4; cyan line: in 1 M Li2SO4.
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f2: Cyclic voltammograms in different electrolytes.(a), for Na0.44MnO2 electrode at a scan rate of 0.5 mVs−1. (b), for LiMn2O4 electrode at a scan rate of 0.1 mVs−1. (c), for carbon-coated TiP2O7 electrode at a scan rate of 0.3 mVs−1. Black line: in 1 M Na2SO4; red line: in 1 M Na2SO4 + 0.125 M Li2SO4; green line: in 1 M Na2SO4 + 0.25 M Li2SO4; blue line: in 1 M Na2SO4 + 0.5 M Li2SO4; cyan line: in 1 M Li2SO4.

Mentions: The electrochemical properties of prepared Na0.44MnO2 in different electrolytes are investigated by cyclic voltammetry (CV) and galvanostatic techniques. Fig. 2a displays three reversible redox couples at ca. 0.05, 0.28 and 0.46 V vs. SCE in aqueous Na2SO4 electrolytes, corresponding to the insertion and extraction of Na+ (ref. 13 and 20). In Li2SO4/Na2SO4 mixed electrolytes, these redox couples still exist, but their potentials are different from the ones in Na2SO4 electrolytes. In Li2SO4 electrolytes, three irreversible oxidation peaks at 0.08 V, 0.31 V, and 0.49 V, attributed to the removal of Na+ from Na0.44MnO2, are observed in the first cycle. Very weak peaks related to Li+ insertion and extraction are seen in the subsequent cycles. It concludes that only a very small amount of Li+ can be reversibly inserted/de-inserted into/from Na0.44MnO2, regardless of its smaller ionic radius (76 pm) compared to Na+ (102 pm). Moreover, Na+ can be selectively extracted and inserted from/into Na0.44MnO2 in the presence of Li+ and Na0.44MnO2 exhibits high selectivity of Na+ towards Li+. Between −0.1 and 0.65 V vs. SCE, the discharge capacities of Na0.44MnO2 in 1 M Na2SO4, 1 M Na2SO4 + 0.125 M Li2SO4, 1 M Na2SO4 + 0.25 M Li2SO4 and 1 M Na2SO4 + 0.5 M Li2SO4 electrolytes are 62.1, 60.7, 60.2 and 57.9 mAh g−1 at 0.25 C rate (1 C = 60 mAh g−1), respectively (Supplementary Fig. S4). These values are much larger than 45 mAh g−1 obtained by Whitacre's group, and agree well with the theoretical capacity of 60 mAh g−1, which indicate that about half of sodium ions in Na0.44MnO2 can be reversibly intercalated into tunnels of Na0.44MnO2 in mixed electrolytes. The unique nanorod shape and good crystallinity of Na0.44MnO2 may account for its high capacity and good reversibility. It is also found that the capacity slightly decreases with an increase of the Li+/Na+ ratio.


New-concept batteries based on aqueous Li+/Na+ mixed-ion electrolytes.

Chen L, Gu Q, Zhou X, Lee S, Xia Y, Liu Z - Sci Rep (2013)

Cyclic voltammograms in different electrolytes.(a), for Na0.44MnO2 electrode at a scan rate of 0.5 mVs−1. (b), for LiMn2O4 electrode at a scan rate of 0.1 mVs−1. (c), for carbon-coated TiP2O7 electrode at a scan rate of 0.3 mVs−1. Black line: in 1 M Na2SO4; red line: in 1 M Na2SO4 + 0.125 M Li2SO4; green line: in 1 M Na2SO4 + 0.25 M Li2SO4; blue line: in 1 M Na2SO4 + 0.5 M Li2SO4; cyan line: in 1 M Li2SO4.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672879&req=5

f2: Cyclic voltammograms in different electrolytes.(a), for Na0.44MnO2 electrode at a scan rate of 0.5 mVs−1. (b), for LiMn2O4 electrode at a scan rate of 0.1 mVs−1. (c), for carbon-coated TiP2O7 electrode at a scan rate of 0.3 mVs−1. Black line: in 1 M Na2SO4; red line: in 1 M Na2SO4 + 0.125 M Li2SO4; green line: in 1 M Na2SO4 + 0.25 M Li2SO4; blue line: in 1 M Na2SO4 + 0.5 M Li2SO4; cyan line: in 1 M Li2SO4.
Mentions: The electrochemical properties of prepared Na0.44MnO2 in different electrolytes are investigated by cyclic voltammetry (CV) and galvanostatic techniques. Fig. 2a displays three reversible redox couples at ca. 0.05, 0.28 and 0.46 V vs. SCE in aqueous Na2SO4 electrolytes, corresponding to the insertion and extraction of Na+ (ref. 13 and 20). In Li2SO4/Na2SO4 mixed electrolytes, these redox couples still exist, but their potentials are different from the ones in Na2SO4 electrolytes. In Li2SO4 electrolytes, three irreversible oxidation peaks at 0.08 V, 0.31 V, and 0.49 V, attributed to the removal of Na+ from Na0.44MnO2, are observed in the first cycle. Very weak peaks related to Li+ insertion and extraction are seen in the subsequent cycles. It concludes that only a very small amount of Li+ can be reversibly inserted/de-inserted into/from Na0.44MnO2, regardless of its smaller ionic radius (76 pm) compared to Na+ (102 pm). Moreover, Na+ can be selectively extracted and inserted from/into Na0.44MnO2 in the presence of Li+ and Na0.44MnO2 exhibits high selectivity of Na+ towards Li+. Between −0.1 and 0.65 V vs. SCE, the discharge capacities of Na0.44MnO2 in 1 M Na2SO4, 1 M Na2SO4 + 0.125 M Li2SO4, 1 M Na2SO4 + 0.25 M Li2SO4 and 1 M Na2SO4 + 0.5 M Li2SO4 electrolytes are 62.1, 60.7, 60.2 and 57.9 mAh g−1 at 0.25 C rate (1 C = 60 mAh g−1), respectively (Supplementary Fig. S4). These values are much larger than 45 mAh g−1 obtained by Whitacre's group, and agree well with the theoretical capacity of 60 mAh g−1, which indicate that about half of sodium ions in Na0.44MnO2 can be reversibly intercalated into tunnels of Na0.44MnO2 in mixed electrolytes. The unique nanorod shape and good crystallinity of Na0.44MnO2 may account for its high capacity and good reversibility. It is also found that the capacity slightly decreases with an increase of the Li+/Na+ ratio.

Bottom Line: Rechargeable batteries made from low-cost and abundant materials operating in safe aqueous electrolytes are attractive for large-scale energy storage.One involves Li(+) insertion/extraction reaction, and the other mainly relates to Na(+) extraction/insertion reaction.Hence, the Li(+)/Na(+) mixed-ion batteries offer promising applications in energy storage and Li(+)/Na(+) separation.

View Article: PubMed Central - PubMed

Affiliation: Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, P R China.

ABSTRACT
Rechargeable batteries made from low-cost and abundant materials operating in safe aqueous electrolytes are attractive for large-scale energy storage. Sodium-ion battery is considered as a potential alternative of current lithium-ion battery. As sodium-intercalation compounds suitable for aqueous batteries are limited, we adopt a novel concept of Li(+)/Na(+) mixed-ion electrolytes to create two batteries (LiMn2O4/Na0.22MnO2 and Na0.44MnO2/TiP2O7), which relies on two electrochemical processes. One involves Li(+) insertion/extraction reaction, and the other mainly relates to Na(+) extraction/insertion reaction. Two batteries exhibit specific energy of 17 Wh kg(-1) and 25 Wh kg(-1) based on the total weight of active electrode materials, respectively. As well, aqueous LiMn2O4/Na0.22MnO2 battery is capable of separating Li(+) and Na(+) due to its specific mechanism unlike the traditional "rocking-chair" lithium-ion batteries. Hence, the Li(+)/Na(+) mixed-ion batteries offer promising applications in energy storage and Li(+)/Na(+) separation.

Show MeSH
Related in: MedlinePlus