Limits...
Expanded graphite embedded with aluminum nanoparticles as superior thermal conductivity anodes for high-performance lithium-ion batteries

View Article: PubMed Central - PubMed

ABSTRACT

The development of high capacity and long-life lithium-ion batteries is a long-term pursuing and under a close scrutiny. Most of the researches have been focused on exploring electrode materials and structures with high store capability of lithium ions and at the same time with a good electrical conductivity. Thermal conductivity of an electrode material will also have significant impacts on boosting battery capacity and prolonging battery lifetime, which is, however, underestimated. Here, we present the development of an expanded graphite embedded with Al metal nanoparticles (EG-MNPs-Al) synthesized by an oxidation-expansion process. The synthesized EG-MNPs-Al material exhibited a typical hierarchical structure with embedded Al metal nanoparticles into the interspaces of expanded graphite. The parallel thermal conductivity was up to 11.6 W·m−1·K−1 with a bulk density of 453 kg·m−3 at room temperature, a 150% improvement compared to expanded graphite (4.6 W·m−1·K−1) owing to the existence of Al metal nanoparticles. The first reversible capacity of EG-MNPs-Al as anode material for lithium ion battery was 480 mAh·g−1 at a current density of 100 mA·g−1, and retained 84% capacity after 300 cycles. The improved cycling stability and system security of lithium ion batteries is attributed to the excellent thermal conductivity of the EG-MNPs-Al anodes.

No MeSH data available.


Investigations on the compositions and crystalline structures of the NFG, EG, and EG-MNPs-Al.(A) XRD patterns of EG (a), EG-MNPs-Al electrode material after 300 cycles (b) and pristine EG-MNPs-Al (c), (B) Raman spectra of NFG, EG and EG-MNPs-Al.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5037376&req=5

f3: Investigations on the compositions and crystalline structures of the NFG, EG, and EG-MNPs-Al.(A) XRD patterns of EG (a), EG-MNPs-Al electrode material after 300 cycles (b) and pristine EG-MNPs-Al (c), (B) Raman spectra of NFG, EG and EG-MNPs-Al.

Mentions: XRD patterns of EG [curve (a)] and EG-MNPs-Al [curve (c)] samples are shown in Fig. 3A. The curve (c) exhibits a sharp (002) characteristic diffraction peak of graphite at 24.2°, and the (002) diffraction peak intensity is stronger than that of the curve (a), and it presents higher crystallinity of EG-MNPs-Al, which is consistent with HRTEM observation. Moreover, the interlayer spacing value d002 of EG-MNPs-Al is 0.375 nm, larger than that of standard graphite 0.34 nm, indicating that large amounts of graphite flakes have been efficiently expanded and EG-MNPs-Al possesses an enlarged interlayer lattice distance. It is in agreement with the results in Fig. 2b. The (111) reflection reveals the characteristic peak of Al, further indicating the presence of Al metal nanoparticles in EG-MNPs-Al. On the XRD pattern of the EG-MNPs-Al electrode at the end of 300th cycle discharge [curve (b)], the Al characteristic peaks of (111) and (311) planes almost disappear and no additional peaks are formed, indicating that the Al nanoparticles have been consumed during the cycling process and crystalline Li-Al alloys have not been formed. Therefore, it is supposed that the LixAl (x = 1~2.25) alloys might be an amorphous compound or it might decompose at the end of the discharge31.


Expanded graphite embedded with aluminum nanoparticles as superior thermal conductivity anodes for high-performance lithium-ion batteries
Investigations on the compositions and crystalline structures of the NFG, EG, and EG-MNPs-Al.(A) XRD patterns of EG (a), EG-MNPs-Al electrode material after 300 cycles (b) and pristine EG-MNPs-Al (c), (B) Raman spectra of NFG, EG and EG-MNPs-Al.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037376&req=5

f3: Investigations on the compositions and crystalline structures of the NFG, EG, and EG-MNPs-Al.(A) XRD patterns of EG (a), EG-MNPs-Al electrode material after 300 cycles (b) and pristine EG-MNPs-Al (c), (B) Raman spectra of NFG, EG and EG-MNPs-Al.
Mentions: XRD patterns of EG [curve (a)] and EG-MNPs-Al [curve (c)] samples are shown in Fig. 3A. The curve (c) exhibits a sharp (002) characteristic diffraction peak of graphite at 24.2°, and the (002) diffraction peak intensity is stronger than that of the curve (a), and it presents higher crystallinity of EG-MNPs-Al, which is consistent with HRTEM observation. Moreover, the interlayer spacing value d002 of EG-MNPs-Al is 0.375 nm, larger than that of standard graphite 0.34 nm, indicating that large amounts of graphite flakes have been efficiently expanded and EG-MNPs-Al possesses an enlarged interlayer lattice distance. It is in agreement with the results in Fig. 2b. The (111) reflection reveals the characteristic peak of Al, further indicating the presence of Al metal nanoparticles in EG-MNPs-Al. On the XRD pattern of the EG-MNPs-Al electrode at the end of 300th cycle discharge [curve (b)], the Al characteristic peaks of (111) and (311) planes almost disappear and no additional peaks are formed, indicating that the Al nanoparticles have been consumed during the cycling process and crystalline Li-Al alloys have not been formed. Therefore, it is supposed that the LixAl (x = 1~2.25) alloys might be an amorphous compound or it might decompose at the end of the discharge31.

View Article: PubMed Central - PubMed

ABSTRACT

The development of high capacity and long-life lithium-ion batteries is a long-term pursuing and under a close scrutiny. Most of the researches have been focused on exploring electrode materials and structures with high store capability of lithium ions and at the same time with a good electrical conductivity. Thermal conductivity of an electrode material will also have significant impacts on boosting battery capacity and prolonging battery lifetime, which is, however, underestimated. Here, we present the development of an expanded graphite embedded with Al metal nanoparticles (EG-MNPs-Al) synthesized by an oxidation-expansion process. The synthesized EG-MNPs-Al material exhibited a typical hierarchical structure with embedded Al metal nanoparticles into the interspaces of expanded graphite. The parallel thermal conductivity was up to 11.6 W·m−1·K−1 with a bulk density of 453 kg·m−3 at room temperature, a 150% improvement compared to expanded graphite (4.6 W·m−1·K−1) owing to the existence of Al metal nanoparticles. The first reversible capacity of EG-MNPs-Al as anode material for lithium ion battery was 480 mAh·g−1 at a current density of 100 mA·g−1, and retained 84% capacity after 300 cycles. The improved cycling stability and system security of lithium ion batteries is attributed to the excellent thermal conductivity of the EG-MNPs-Al anodes.

No MeSH data available.