Dataset Information

Microwave-Assisted Synthesis of Ge/GeO₂-Reduced Graphene Oxide Nanocomposite with Enhanced Discharge Capacity for Lithium-Ion Batteries.

ABSTRACT: Germanium/germanium oxide nanoparticles with theoretically high discharge capacities of 1624 and 2152 mAh/g have attracted significant research interest for their potential application as anode materials in Li-ion batteries. However, these materials exhibit poor long-term performance due to the large volume change of 370% during charge/discharge cycles. In the present study, to overcome this shortcoming, a Ge/GeO₂/graphene composite material was synthesized. Ge/GeO₂ nanoparticles were trapped between matrices of graphene nanosheets to offset the volume expansion effect. Transmission electron microscopy images revealed that the Ge/GeO₂ nanoparticles were distributed on the graphene nanosheets. Discharge/charge experiments were performed to evaluate the Li storage properties of the samples. The discharge capacity of the bare Ge/GeO₂ nanoparticles in the first discharge cycle was considerably large; however, the value decreased rapidly with successive cycles. Conversely, the present Ge/GeO₂/graphene composite exhibited superior cycling stability.

SUBMITTER: Koo JH

PROVIDER: S-EPMC7911565 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Publications

Microwave-Assisted Synthesis of Ge/GeO2-Reduced Graphene Oxide Nanocomposite with Enhanced Discharge Capacity for Lithium-Ion Batteries.

Koo Ji-Hye JH Paek Seung-Min SM

Nanomaterials (Basel, Switzerland) 20210127 2

Germanium/germanium oxide nanoparticles with theoretically high discharge capacities of 1624 and 2152 mAh/g have attracted significant research interest for their potential application as anode materials in Li-ion batteries. However, these materials exhibit poor long-term performance due to the large volume change of 370% during charge/discharge cycles. In the present study, to overcome this shortcoming, a Ge/GeO2/graphene composite material was synthesized. Ge/GeO2 nanopar ...[more]

PMID: 33513759

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Project description:Li-S batteries (LSBs) require a minimum 6 mAh cm-2 areal capacity to compete with the state-of-the-art lithium ion batteries (LIBs). However, this areal capacity is difficult to achieve due to a major technical issue-the shuttle effect. Nonpolar carbon materials limit the shuttle effect through physical confinement. However, the polar polysulfides (PSs) only provide weak intermolecular interactions (0.1-0.7 eV) with these nonpolar carbon materials. The physically encapsulated PSs inside the nonpolar carbon scaffold eventually diffuses out and starts shuttling. Chemically interactive hosts are more effective at interacting with the PSs due to high binding energies. Herein, a multifunctional separator coating of nitrogen-doped multilayer graphene (NGN) and -SO3 - containing Nafion (N-NGN) is used to mitigate PS shuttling and to produce a high areal capacity LSB. The Nafion is used as a binder instead of PVDF to provide an additional advantage of -SO3 - to chemically bind the PS. The motive of this research is to investigate the effect of highly electronegative N and -SO3 - (N-NGN) in comparison with the -OH, -COOH, and -SO3 - groups from a hydroxyl graphene and Nafion composite (N-OHGN) to mitigate PS shuttling in LSBs. The highly conductive doped graphene architecture (N-NGN) provides efficient pathways for both electrons and ions, which accelerates the electrochemical conversion at high sulfur loading. Moreover, the electron-rich pyridine N and -SO3 - show strong chemical affinity with the PS through polar-polar interactions, which is proven by the superior electrochemical performance and density functional theory calculations. Further, the N-NGN (5 h) produces a maximum areal capacity of 12.0 and 11.0 mAh cm-2, respectively, at 15 and 12 mg cm-2 sulfur loading. This areal capacity limit is significantly higher than the required areal capacity of LSBs for commercial application, which shows the significant strength of N-NGN as an excellent separator coating for LSBs.

Dataset Information

Microwave-Assisted Synthesis of Ge/GeO₂-Reduced Graphene Oxide Nanocomposite with Enhanced Discharge Capacity for Lithium-Ion Batteries.

Publications

Microwave-Assisted Synthesis of Ge/GeO<sub>2</sub>-Reduced Graphene Oxide Nanocomposite with Enhanced Discharge Capacity for Lithium-Ion Batteries.

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