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Cheap glass fiber mats as a matrix of gel polymer electrolytes for lithium ion batteries.

Zhu Y, Wang F, Liu L, Xiao S, Yang Y, Wu Y - Sci Rep (2013)

Bottom Line: Gel polymer electrolytes (GPEs) have been tried to replace the organic electrolyte to improve their safety.However, the application of GPEs is handicapped by their poor mechanical strength and high cost.The results show this gel-type composite membrane has great attraction to the large-capacity LIBs requiring high safety with low cost.

View Article: PubMed Central - PubMed

Affiliation: New Energy and Materials Laboratory (NEML), Department of Chemistry & Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, China.

ABSTRACT
Lithium ion batteries (LIBs) are going to play more important roles in electric vehicles and smart grids. The safety of the current LIBs of large capacity has been remaining a challenge due to the existence of large amounts of organic liquid electrolytes. Gel polymer electrolytes (GPEs) have been tried to replace the organic electrolyte to improve their safety. However, the application of GPEs is handicapped by their poor mechanical strength and high cost. Here, we report an economic gel-type composite membrane with high safety and good mechanical strength based on glass fiber mats, which are separator for lead-acid batteries. The gelled membrane exhibits high ionic conductivity (1.13 mS cm(-1)), high Li(+) ion transference number (0.56) and wide electrochemical window. Its electrochemical performance is evaluated by LiFePO4 cathode with good cycling. The results show this gel-type composite membrane has great attraction to the large-capacity LIBs requiring high safety with low cost.

No MeSH data available.


Related in: MedlinePlus

Electrochemical performance of the LiFePO4 cathode.(a) Cycling behavior and the charge-discharge curves at 1st, 5th and 10th cycles; and (b) rate behaviour and discharge curves at a charge current density of 0.2 C and discharge current density of 0.1 C, 0.2 C, 0.5 C, 1 C and 0.1 C, respectively. These were measured by using the Celgard 2730 or the PVDF-GFM composite membrane as separtors saturating with 1 mol L−1 LiPF6 electrolyte and Li metal as the counter and reference electrode.
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f5: Electrochemical performance of the LiFePO4 cathode.(a) Cycling behavior and the charge-discharge curves at 1st, 5th and 10th cycles; and (b) rate behaviour and discharge curves at a charge current density of 0.2 C and discharge current density of 0.1 C, 0.2 C, 0.5 C, 1 C and 0.1 C, respectively. These were measured by using the Celgard 2730 or the PVDF-GFM composite membrane as separtors saturating with 1 mol L−1 LiPF6 electrolyte and Li metal as the counter and reference electrode.

Mentions: The electrochemical performance of the gel PVDF-GFM membranes was evaluated by using LiFePO4 as the cathode and Li metal as the counter and reference electrode (Figure 5). The reversible capacity of LiFePO4 is about 125 mAh g−1 at 0.2 C for the gel membrane, which is higher than that for the commercial separator, about 100 mAh g−1 (Figure 5a). The cycling performance of the gel membrane is similar to that of the commercial separator. After 25 cycles there is still no evident capacity fading. From the corresponding charge-discharge curves, typical flat-shaped voltage profiles are observed around 3.2–3.5 V in the case of the gel membrane (Inset of Figure 5a), which are consistent with the reported coexistence reaction of two phases for the LiFePO4 cathode293031, and the difference between charge and discharge curves is very small, less than 0.3 V. In the case of the Celgard 2730, the voltage profiles for the LiFePO4 are also flat (Inset of Figure 5a). However, the difference between charge and discharge voltages is larger, at least 0.8 V. Evidently, this higher voltage difference is due to the polarizations caused by the lower transference amount of Li+ ions. In addition, the gel membrane also presents satisfactory rate performance (Figure 5b) between 0.1 C and 1 C. When the composite was charged at 0.2 C and discharged at 0.1 C, 0.2 C, 0.5 C and 1 C, the capacity of the LiFePO4 tested with the gel PVDF-GFM is 118.7, 125.8, 115.3 and 103.1 mAh g−1, respectively, which is higher than that of the wetted Celgard 2730 (108.7, 100.5, 89.5, and 74.7 mAh g−1, respectively). When discharged with 0.1 C at last, the discharge capacity is recovered to the original value. Capacity retention and Coulombic efficience of the gel PVDF-GFM membrane in 40 cycles is very stable (Supplementary Fig. S3).


Cheap glass fiber mats as a matrix of gel polymer electrolytes for lithium ion batteries.

Zhu Y, Wang F, Liu L, Xiao S, Yang Y, Wu Y - Sci Rep (2013)

Electrochemical performance of the LiFePO4 cathode.(a) Cycling behavior and the charge-discharge curves at 1st, 5th and 10th cycles; and (b) rate behaviour and discharge curves at a charge current density of 0.2 C and discharge current density of 0.1 C, 0.2 C, 0.5 C, 1 C and 0.1 C, respectively. These were measured by using the Celgard 2730 or the PVDF-GFM composite membrane as separtors saturating with 1 mol L−1 LiPF6 electrolyte and Li metal as the counter and reference electrode.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824160&req=5

f5: Electrochemical performance of the LiFePO4 cathode.(a) Cycling behavior and the charge-discharge curves at 1st, 5th and 10th cycles; and (b) rate behaviour and discharge curves at a charge current density of 0.2 C and discharge current density of 0.1 C, 0.2 C, 0.5 C, 1 C and 0.1 C, respectively. These were measured by using the Celgard 2730 or the PVDF-GFM composite membrane as separtors saturating with 1 mol L−1 LiPF6 electrolyte and Li metal as the counter and reference electrode.
Mentions: The electrochemical performance of the gel PVDF-GFM membranes was evaluated by using LiFePO4 as the cathode and Li metal as the counter and reference electrode (Figure 5). The reversible capacity of LiFePO4 is about 125 mAh g−1 at 0.2 C for the gel membrane, which is higher than that for the commercial separator, about 100 mAh g−1 (Figure 5a). The cycling performance of the gel membrane is similar to that of the commercial separator. After 25 cycles there is still no evident capacity fading. From the corresponding charge-discharge curves, typical flat-shaped voltage profiles are observed around 3.2–3.5 V in the case of the gel membrane (Inset of Figure 5a), which are consistent with the reported coexistence reaction of two phases for the LiFePO4 cathode293031, and the difference between charge and discharge curves is very small, less than 0.3 V. In the case of the Celgard 2730, the voltage profiles for the LiFePO4 are also flat (Inset of Figure 5a). However, the difference between charge and discharge voltages is larger, at least 0.8 V. Evidently, this higher voltage difference is due to the polarizations caused by the lower transference amount of Li+ ions. In addition, the gel membrane also presents satisfactory rate performance (Figure 5b) between 0.1 C and 1 C. When the composite was charged at 0.2 C and discharged at 0.1 C, 0.2 C, 0.5 C and 1 C, the capacity of the LiFePO4 tested with the gel PVDF-GFM is 118.7, 125.8, 115.3 and 103.1 mAh g−1, respectively, which is higher than that of the wetted Celgard 2730 (108.7, 100.5, 89.5, and 74.7 mAh g−1, respectively). When discharged with 0.1 C at last, the discharge capacity is recovered to the original value. Capacity retention and Coulombic efficience of the gel PVDF-GFM membrane in 40 cycles is very stable (Supplementary Fig. S3).

Bottom Line: Gel polymer electrolytes (GPEs) have been tried to replace the organic electrolyte to improve their safety.However, the application of GPEs is handicapped by their poor mechanical strength and high cost.The results show this gel-type composite membrane has great attraction to the large-capacity LIBs requiring high safety with low cost.

View Article: PubMed Central - PubMed

Affiliation: New Energy and Materials Laboratory (NEML), Department of Chemistry & Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, China.

ABSTRACT
Lithium ion batteries (LIBs) are going to play more important roles in electric vehicles and smart grids. The safety of the current LIBs of large capacity has been remaining a challenge due to the existence of large amounts of organic liquid electrolytes. Gel polymer electrolytes (GPEs) have been tried to replace the organic electrolyte to improve their safety. However, the application of GPEs is handicapped by their poor mechanical strength and high cost. Here, we report an economic gel-type composite membrane with high safety and good mechanical strength based on glass fiber mats, which are separator for lead-acid batteries. The gelled membrane exhibits high ionic conductivity (1.13 mS cm(-1)), high Li(+) ion transference number (0.56) and wide electrochemical window. Its electrochemical performance is evaluated by LiFePO4 cathode with good cycling. The results show this gel-type composite membrane has great attraction to the large-capacity LIBs requiring high safety with low cost.

No MeSH data available.


Related in: MedlinePlus