| 1. |
- Wang, Zhuyi, et al.
(författare)
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Self-Assembly of PEI/SiO2 on Polyethylene Separators for Li-Ion Batteries with Enhanced Rate Capability
- 2015
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 7:5, s. 3314-3322
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Tidskriftsartikel (refereegranskat)abstract
- A simple and environmentally friendly self-assembly process of oppositely charged polymer PEI and inorganic oxide SiO2 was demonstrated for the construction of an ultrathin layer on the surface of PE separator. The XPS, FT-IR, SEM, and EDS characterizations give clear evidence of the successful self-assembly of PEI and SiO2 without significantly increasing the thickness and sacrificing the pristine porous structure of PE separator. This process improves a variety of crucial properties of PE separator such as the electrolyte wetting, the electrolyte uptake, the thermal stability, the ionic conductivity, Li+ transference number, the electrochemical stability and the compatibility with lithium electrode, endowing lithium-ion battery (Li as anode and LiCoO2 as cathode) with excellent capacity retention at high C-rates and superior cycling performance. At the current density of 5 C, the cell with PE separator almost loses all the capacity. In contrast, the cell with (PEI/SiO2)-modified PE separator still holds 45.2% of the discharge capacity at 0.2 C. The stabilized SEI formation and high Li+ transference number of (PEI/SiO2)-modified PE separator were interpreted to be the substantial reasons leading to the remarkably enhanced battery performance, rendering some new insights into the role of the separator in lithium-ion batteries.
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| 2. |
- Xu, Haiping, et al.
(författare)
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Fluorine-Doped Tin Oxide Nanocrystal/Reduced Graphene Oxide Composites as Lithium Ion Battery Anode Material with High Capacity and Cycling Stability
- 2015
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 7:49, s. 27486-27493
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Tidskriftsartikel (refereegranskat)abstract
- Tin oxide (SnO2) is a kind of anode material with high theoretical capacity. However, the volume expansion and fast capability fading during cycling have prevented its practical application in lithium ion batteries. Herein, we report that the nanocomposite of fluorine-doped tin oxide (FTO) and reduced graphene oxide (RGO) is an ideal anode material with high capacity, high rate capability, and high stability. The FTO conductive nanocrystals were successfully anchored on RGO nanosheets from an FTO nanocrystals colloid and RGO suspension by hydrothermal treatment. As the anode material, the FTO/RGO composite showed high structural stability during the lithiation and delithiation processes. The conductive FTO nanocrystals favor the formation of stable and thin solid electrolyte interface films. Significantly, the FTO/RGO composite retains a discharge capacity as high as 1439 mAhg(-1) after 200 cycles at a current density of 100 mAg(-1). Moreover, its rate capacity displays 1148 mAhg(-1) at a current density of 1000 mAg(-1).
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| 3. |
- Xu, Wuxia, et al.
(författare)
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Layer-by-Layer Deposition of Organic-Inorganic Hybrid Multilayer on Microporous Polyethylene Separator to Enhance the Electrochemical Performance of Lithium-Ion Battery
- 2015
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 7:37, s. 20678-20686
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Tidskriftsartikel (refereegranskat)abstract
- A simple layer-by-layer (LbL) self-assembly process of poly(acrylic acid) (PAA) and ZrO2 was applied to construct functional ultrathin multilayers on polyethylene (PE) separators without sacrificing the excellent porous structure of separators. Such PAA/ZrO2 LbL-modified PE separators possess good electrolyte wettability, excellent electrolyte uptake, high ionic conductivity and large Li+ transference number. More importantly, the top layer of LbL self-assembly would affect the dissociation of electrolyte and the formation of solid electrolyte interphase (SEI) layer in half-cells. Compared with the pristine and (PAA/ZrO2)(1)PAA-modified PE separators, (PAA/ZrO2)(3)-modified PE separator shows a larger Li+ transference number (0.6) and a faster tendency to form a stable SEI layer, endowing half-cells with excellent capacity retention at high C-rates and superior cycling performance. These fascinating characteristics will provide the LbL self-assembly with a promising method to improve the surface property of PE separators for high performance lithium-ion batteries.
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