Surface Oxidation of Nano-Silicon as a Method for Cycle Life Enhancement of Li-ion Active Materials

Ratyński, Maciej; Hamankiewicz, Bartosz; Buchberger, Dominika A.; Czerwiński, Andrzej

doi:10.3390/molecules25184093

Cited by 8 publications

(9 citation statements)

References 48 publications

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“…8, correspond to Si and O, which suggests that silicon or silicon oxide particles were added to increase cell energy density. 17 O and Si are clearly co-located in the single element maps in the SI. The small white spots that cover the surface in the Figs.…”

Section: Resultsmentioning

confidence: 96%

Characterization of Cycle-Aged Commercial NMC and NCA Lithium-ion Cells: I. Temperature-Dependent Degradation

Wittman,

Dubarry,

Ivanov

et al. 2023

J. Electrochem. Soc.

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Lithium-ion batteries are widely used in applications from consumer electronic devices to stationary energy storage. Appropriate management of batteries is challenging due to limited data on their performance and materials degradation. Previous studies have focused on characterization of single cells under specific operating conditions. In the present work, commercial 18650 lithium-ion cells with LiNixMnyCo1-x-yO2 (NMC) and LiNixCoyAl1-x-yO2 (NCA) positive electrodes were characterized by a wide range of electrochemical and materials techniques after cycling at 15, 25, or 35 °C to ∼80% capacity. The NCA cells exhibit weak temperature dependence in their cycle aging and materials degradation. The NMC cells exhibited increased capacity fade and materials degradation as ambient temperature decreased. All cells exhibited loss of lithium inventory as their primary degradation mode. However, the NCA cells only showed evidence of solid electrolyte interphase (SEI) growth whereas the NMC cells showed signs of Li plating at 15 °C, transitioning to SEI growth at 35 °C. The NMC cells displayed signs of loss of active material at the positive electrode at lower temperatures, suggesting that Li plating is correlated to additional processes that increase the rate of degradation. These results highlight the importance of avoiding broad generalizations about Li-ion battery temperature dependence.

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Section: Resultsmentioning

confidence: 96%

Characterization of Cycle-Aged Commercial NMC and NCA Lithium-ion Cells: I. Temperature-Dependent Degradation

Wittman,

Dubarry,

Ivanov

et al. 2023

J. Electrochem. Soc.

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“…With increasing scan rate, the two cathodic peaks appear less distinctive and the anodic peak at 300 mV seems to be suppressed compared to the peak at 540 mV. Especially for the second anodic peak (at 540 mV in the case of 0.1 mV/s), it is observed that with increasing scan rate, the peak shifts toward positive potential values; for 0.8 mV/s rate, as compared to 0.1 mV/s, the peak has shifted more than 100 mV due to electrode kinetics [52]. Similar behavior can be seen for the Si_Gr electrode, in Figure 5b, with the difference to the Si sample, that all corresponding peaks appear at lower potentials of around 50 mV, which is mostly due to the higher electron conduction within the electrode provided by the addition of graphene.…”

Section: Tablementioning

confidence: 85%

Study of the Role of Void and Residual Silicon Dioxide on the Electrochemical Performance of Silicon Nanoparticles Encapsulated by Graphene

et al. 2021

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Silicon nanoparticles are used to enhance the anode specific capacity for the lithium-ion cell technology. Due to the mechanical deficiencies of silicon during lithiation and delithiation, one of the many strategies that have been proposed consists of enwrapping the silicon nanoparticles with graphene and creating a void area between them so as to accommodate the large volume changes that occur in the silicon nanoparticle. This work aims to investigate the electrochemical performance and the associated kinetics of the hollow outer shell nanoparticles. To this end, we prepared hollow outer shell silicon nanoparticles (nps) enwrapped with graphene by using thermally grown silicon dioxide as a sacrificial layer, ball milling to enwrap silicon particles with graphene and hydro fluorine (HF) to etch the sacrificial SiO2 layer. In addition, in order to offer a wider vision on the electrochemical behavior of the hollow outer shell Si nps, we also prepared all the possible in-between process stages of nps and corresponding electrodes (i.e., bare Si nps, bare Si nps enwrapped with graphene, Si/SiO2 nps and Si/SiO2 nps enwrapped with graphene). The morphology of all particles revealed the existence of graphene encapsulation, void, and a residual layer of silicon dioxide depending on the process of each nanoparticle. Corresponding electrodes were prepared and studied in half cell configurations by means of galvanostatic cycling, cyclic voltammetry and electrochemical impedance spectroscopy. It was observed that nanoparticles encapsulated with graphene demonstrated high specific capacity but limited cycle life. In contrast, nanoparticles with void and/or SiO2 were able to deliver improved cycle life. It is suggested that the existence of the void and/or residual SiO2 layer limits the formation of rich LiXSi alloys in the core silicon nanoparticle, providing higher mechanical stability during the lithiation and delithiation processes.

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“…Since RP-SiMP/GO has a higher carbon weight ratio than RP-SiMP/LSG as shown in Figure e and both GO and LSG have one to two orders of magnitude higher specific surface area than silicon microparticles, more SEI layers likely form on the carbon in RP-SiMP/GO, resulting in a higher irreversible capacity. Also, it is known that the formation of silicon oxide layers on pure silicon alleviates the volume change of silicon particles by suppressing unnecessary SEI formation. − Since SiMPs in the RP-SiMP/LSG electrode form SiO x and SiC layers on the surface as shown in the XRD in Figure f, RP-SiMP/LSG exhibited a smaller irreversible capacity than RP-SiMP/GO. The lower reversible capacity of RP-SiMP/LSG compared to RP-SiMP/GO in the initial cycle can be attributed to the formation of silicon oxides and SiC.…”

Section: Resultsmentioning

confidence: 99%

“…Thereafter, a CO 2 laser is applied to a film of SiMP/GO to reduce GO to laser-scribed graphene (LSG). − Simultaneously, SiO x and SiC layers form on the SiMPs through a laser process. These coatings act as protection layers to alleviate the severe volume changes of the SiMPs and therefore suppress unnecessary SEI formation. − Owing to the formation of the wrapping structure and the SiO x and SiC protection layers, SiMP/LSG prepared by the modified reprecipitation method (RP-SiMP/LSG) exhibits an improved cycling life compared to SiMP/graphene/CMC composites prepared by a simple mixing method (SM-SiMP/graphene/CMC). The modified reprecipitation method combined with the laser reduction under air is a simple, rapid, room-temperature, and therefore scalable process, which is a new synthesis approach in this field and could potentially solve the current challenges that occur when trying to create SiMP wrapping structures.…”

Section: Introductionmentioning

confidence: 99%

Reprecipitation: A Rapid Synthesis of Micro-Sized Silicon-Graphene Composites for Long-lasting Lithium-Ion Batteries

Katsuyama,

Li,

Uemura

et al. 2024

ACS Appl. Mater. Interfaces

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Silicon microparticles (SiMPs) have gained significant attention as a lithium-ion battery anode material due to their 10 times higher theoretical capacity compared to conventional graphite anodes as well as their much lower production cost than silicon nanoparticles (SiNPs). However, SiMPs have suffered from poorer cycle life relative to SiNPs because their larger size makes them more susceptible to volume changes during charging and discharging. Creating a wrapping structure in which SiMPs are enveloped by carbon layers has proven to be an effective strategy to significantly improve the cycling performance of SiMPs. However, the synthesis processes are complex and time-/energy-consuming and therefore not scalable. In this study, a wrapping structure is created by using a simple, rapid, and scalable “modified reprecipitation method”. Graphene oxide (GO) and SiMP dispersion in tetrahydrofuran is injected into n-hexane, in which GO and SiMP by themselves cannot disperse. GO and SiMP therefore aggregate and precipitate immediately after injection to form a wrapping structure. The resulting SiMP/GO film is laser scribed to reduce GO to a laser-scribed graphene (LSG). Simultaneously, SiO x and SiC protection layers form on the SiMPs through the laser process, which alleviates severe volume change. Owing to these desirable characteristics, the modified reprecipitation method successfully doubles the cycle life of SiMP/graphene composites compared to the simple physically mixing method (50.2% vs. 24.0% retention at the 100th cycle). The modified reprecipitation method opens a new synthetic strategy for SiMP/carbon composites.

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Surface Oxidation of Nano-Silicon as a Method for Cycle Life Enhancement of Li-ion Active Materials

Cited by 8 publications

References 48 publications

Characterization of Cycle-Aged Commercial NMC and NCA Lithium-ion Cells: I. Temperature-Dependent Degradation

Characterization of Cycle-Aged Commercial NMC and NCA Lithium-ion Cells: I. Temperature-Dependent Degradation

Study of the Role of Void and Residual Silicon Dioxide on the Electrochemical Performance of Silicon Nanoparticles Encapsulated by Graphene

Reprecipitation: A Rapid Synthesis of Micro-Sized Silicon-Graphene Composites for Long-lasting Lithium-Ion Batteries

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