Limits...
Silicon carbide-free graphene growth on silicon for lithium-ion battery with high volumetric energy density.

Son IH, Hwan Park J, Kwon S, Park S, Rümmeli MH, Bachmatiuk A, Song HJ, Ku J, Choi JW, Choi JM, Doo SG, Chang H - Nat Commun (2015)

Bottom Line: However, the large volume change of silicon over charge-discharge cycles weakens its competitiveness in the volumetric energy density and cycle life.Here we report direct graphene growth over silicon nanoparticles without silicon carbide formation.The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers.

View Article: PubMed Central - PubMed

Affiliation: Energy Material Lab, Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803, Republic of Korea.

ABSTRACT
Silicon is receiving discernable attention as an active material for next generation lithium-ion battery anodes because of its unparalleled gravimetric capacity. However, the large volume change of silicon over charge-discharge cycles weakens its competitiveness in the volumetric energy density and cycle life. Here we report direct graphene growth over silicon nanoparticles without silicon carbide formation. The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers. When paired with a commercial lithium cobalt oxide cathode, the silicon carbide-free graphene coating allows the full cell to reach volumetric energy densities of 972 and 700 Wh l(-1) at first and 200th cycle, respectively, 1.8 and 1.5 times higher than those of current commercial lithium-ion batteries. This observation suggests that two-dimensional layered structure of graphene and its silicon carbide-free integration with silicon can serve as a prototype in advancing silicon anodes to commercially viable technology.

No MeSH data available.


Related in: MedlinePlus

Conductivity and electrochemical analysis.(a) The pellet conductivities of Gr–Si, AC–Si and Super P–Si at different carbon contents. (b) The first lithiation–delithiation profiles. The electrode thicknesses of 5 wt%-Gr–Si, 1 wt%-Gr–Si, 2 wt%-AC–Si and pristine Si (Super P 1 wt%) are 4.5, 5.0, 8.3 and 12.3 μm, respectively. (c) The lithiation (filled circle) and delithiation (open circle) capacity retentions of the same four samples. The potential was swept within a voltage window between 0.01 and 1.5 V at 0.5C. (d) The top-viewed SEM images: the 5 wt%-Gr–Si electrode (left) before and (middle) after 200 cycles and (right) the 2 wt%-AC–Si electrode after 200 cycles. (e) A high-magnification TEM image of 5 wt%-Gr–Si after 200 cycles obtained from the white box in the low-magnification TEM image (top inset). Middle inset: selected area electron diffraction showing amorphous nature of Si after cycling. Bottom inset: a line profile from the graphene layers in the red box displaying an interlayer distance of 3.8 Å. (f) Rate capability of 5 wt%-Gr–Si with different initial areal capacities (3.0, 2.0 and 1.0 mAh cm−2).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4491181&req=5

f4: Conductivity and electrochemical analysis.(a) The pellet conductivities of Gr–Si, AC–Si and Super P–Si at different carbon contents. (b) The first lithiation–delithiation profiles. The electrode thicknesses of 5 wt%-Gr–Si, 1 wt%-Gr–Si, 2 wt%-AC–Si and pristine Si (Super P 1 wt%) are 4.5, 5.0, 8.3 and 12.3 μm, respectively. (c) The lithiation (filled circle) and delithiation (open circle) capacity retentions of the same four samples. The potential was swept within a voltage window between 0.01 and 1.5 V at 0.5C. (d) The top-viewed SEM images: the 5 wt%-Gr–Si electrode (left) before and (middle) after 200 cycles and (right) the 2 wt%-AC–Si electrode after 200 cycles. (e) A high-magnification TEM image of 5 wt%-Gr–Si after 200 cycles obtained from the white box in the low-magnification TEM image (top inset). Middle inset: selected area electron diffraction showing amorphous nature of Si after cycling. Bottom inset: a line profile from the graphene layers in the red box displaying an interlayer distance of 3.8 Å. (f) Rate capability of 5 wt%-Gr–Si with different initial areal capacities (3.0, 2.0 and 1.0 mAh cm−2).

Mentions: Upon graphene growth, the conductivity of the active material assembly becomes markedly enhanced. When pelletized in powder, pristine Si exhibited a low conductivity of <10−7 S cm−1, whereas even 1 wt% of graphene addition increased the conductivity remarkably to 12.8 S cm−1 (Fig. 4a). This enhancement is ascribed to an excellent percolation behaviour of the graphene coating layers in a way that the 2D graphene and its well-aligned layered stacking promote a well-connected conductive network (Supplementary Fig. 7), and is also in line with previous graphene–polymer composites39. The conductivity increased further to 38.3 S cm−1 for a graphene content of 5 wt%.


Silicon carbide-free graphene growth on silicon for lithium-ion battery with high volumetric energy density.

Son IH, Hwan Park J, Kwon S, Park S, Rümmeli MH, Bachmatiuk A, Song HJ, Ku J, Choi JW, Choi JM, Doo SG, Chang H - Nat Commun (2015)

Conductivity and electrochemical analysis.(a) The pellet conductivities of Gr–Si, AC–Si and Super P–Si at different carbon contents. (b) The first lithiation–delithiation profiles. The electrode thicknesses of 5 wt%-Gr–Si, 1 wt%-Gr–Si, 2 wt%-AC–Si and pristine Si (Super P 1 wt%) are 4.5, 5.0, 8.3 and 12.3 μm, respectively. (c) The lithiation (filled circle) and delithiation (open circle) capacity retentions of the same four samples. The potential was swept within a voltage window between 0.01 and 1.5 V at 0.5C. (d) The top-viewed SEM images: the 5 wt%-Gr–Si electrode (left) before and (middle) after 200 cycles and (right) the 2 wt%-AC–Si electrode after 200 cycles. (e) A high-magnification TEM image of 5 wt%-Gr–Si after 200 cycles obtained from the white box in the low-magnification TEM image (top inset). Middle inset: selected area electron diffraction showing amorphous nature of Si after cycling. Bottom inset: a line profile from the graphene layers in the red box displaying an interlayer distance of 3.8 Å. (f) Rate capability of 5 wt%-Gr–Si with different initial areal capacities (3.0, 2.0 and 1.0 mAh cm−2).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4491181&req=5

f4: Conductivity and electrochemical analysis.(a) The pellet conductivities of Gr–Si, AC–Si and Super P–Si at different carbon contents. (b) The first lithiation–delithiation profiles. The electrode thicknesses of 5 wt%-Gr–Si, 1 wt%-Gr–Si, 2 wt%-AC–Si and pristine Si (Super P 1 wt%) are 4.5, 5.0, 8.3 and 12.3 μm, respectively. (c) The lithiation (filled circle) and delithiation (open circle) capacity retentions of the same four samples. The potential was swept within a voltage window between 0.01 and 1.5 V at 0.5C. (d) The top-viewed SEM images: the 5 wt%-Gr–Si electrode (left) before and (middle) after 200 cycles and (right) the 2 wt%-AC–Si electrode after 200 cycles. (e) A high-magnification TEM image of 5 wt%-Gr–Si after 200 cycles obtained from the white box in the low-magnification TEM image (top inset). Middle inset: selected area electron diffraction showing amorphous nature of Si after cycling. Bottom inset: a line profile from the graphene layers in the red box displaying an interlayer distance of 3.8 Å. (f) Rate capability of 5 wt%-Gr–Si with different initial areal capacities (3.0, 2.0 and 1.0 mAh cm−2).
Mentions: Upon graphene growth, the conductivity of the active material assembly becomes markedly enhanced. When pelletized in powder, pristine Si exhibited a low conductivity of <10−7 S cm−1, whereas even 1 wt% of graphene addition increased the conductivity remarkably to 12.8 S cm−1 (Fig. 4a). This enhancement is ascribed to an excellent percolation behaviour of the graphene coating layers in a way that the 2D graphene and its well-aligned layered stacking promote a well-connected conductive network (Supplementary Fig. 7), and is also in line with previous graphene–polymer composites39. The conductivity increased further to 38.3 S cm−1 for a graphene content of 5 wt%.

Bottom Line: However, the large volume change of silicon over charge-discharge cycles weakens its competitiveness in the volumetric energy density and cycle life.Here we report direct graphene growth over silicon nanoparticles without silicon carbide formation.The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers.

View Article: PubMed Central - PubMed

Affiliation: Energy Material Lab, Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803, Republic of Korea.

ABSTRACT
Silicon is receiving discernable attention as an active material for next generation lithium-ion battery anodes because of its unparalleled gravimetric capacity. However, the large volume change of silicon over charge-discharge cycles weakens its competitiveness in the volumetric energy density and cycle life. Here we report direct graphene growth over silicon nanoparticles without silicon carbide formation. The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers. When paired with a commercial lithium cobalt oxide cathode, the silicon carbide-free graphene coating allows the full cell to reach volumetric energy densities of 972 and 700 Wh l(-1) at first and 200th cycle, respectively, 1.8 and 1.5 times higher than those of current commercial lithium-ion batteries. This observation suggests that two-dimensional layered structure of graphene and its silicon carbide-free integration with silicon can serve as a prototype in advancing silicon anodes to commercially viable technology.

No MeSH data available.


Related in: MedlinePlus