Reduced Silicon Fragmentation in Lithium Ion Battery Anodes Using Electronic Doping Strategies

Lau, Derwin; Hall, Charles A. S.; Lim, Sean; Yuwono, Jodie A.; Burr, Patrick A.; Song, Ning; Lennon, Alison

doi:10.1021/acsaem.9b02200

Cited by 21 publications

(39 citation statements)

References 64 publications

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“…On the contrary, the capacity of the LIB with an n-SiNW electrode demonstrated capacity retention of 76.7% at 0.2 mA cm −2 , and restored 97.1% of its capacity when the discharge rate was reduced back to 0.02 mA cm −2 . In this case, the vertical arrangement of the nanowires provided a facile and fast Li ion diffusion pathway, resulting in the measured improved capacity retention at high current rates [15,43]. The good rate performance of LIBs with n-SiNW electrodes is also ascribed to the fast infiltration and circulation of the electrolyte in the nanowire array electrode, facilitating rapid ion transport during the electrochemical reactions [8].…”

Section: Resultsmentioning

confidence: 96%

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Vertically Aligned n-Type Silicon Nanowire Array as a Free-Standing Anode for Lithium-Ion Batteries

et al. 2021

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Due to its high theoretical specific capacity, a silicon anode is one of the candidates for realizing high energy density lithium-ion batteries (LIBs). However, problems related to bulk silicon (e.g., low intrinsic conductivity and massive volume expansion) limit the performance of silicon anodes. In this work, to improve the performance of silicon anodes, a vertically aligned n-type silicon nanowire array (n-SiNW) was fabricated using a well-controlled, top-down nano-machining technique by combining photolithography and inductively coupled plasma reactive ion etching (ICP-RIE) at a cryogenic temperature. The array of nanowires ~1 µm in diameter and with the aspect ratio of ~10 was successfully prepared from commercial n-type silicon wafer. The half-cell LIB with free-standing n-SiNW electrode exhibited an initial Coulombic efficiency of 91.1%, which was higher than the battery with a blank n-silicon wafer electrode (i.e., 67.5%). Upon 100 cycles of stability testing at 0.06 mA cm−2, the battery with the n-SiNW electrode retained 85.9% of its 0.50 mAh cm−2 capacity after the pre-lithiation step, whereas its counterpart, the blank n-silicon wafer electrode, only maintained 61.4% of 0.21 mAh cm−2 capacity. Furthermore, 76.7% capacity retention can be obtained at a current density of 0.2 mA cm−2, showing the potential of n-SiNW anodes for high current density applications. This work presents an alternative method for facile, high precision, and high throughput patterning on a wafer-scale to obtain a high aspect ratio n-SiNW, and its application in LIBs.

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Section: Resultsmentioning

confidence: 96%

“…The diffraction peak at 2θ = 69.13 • for the plain/blank Si wafer and the n-SiNW corresponds to the <400> crystal orientation as the first reflection from <100>-Si [42]. An n-type Si with <100> orientation enables faster diffusion of Li ions, which is beneficial for reducing the volume expansion of Si anodes [43].…”

Section: Resultsmentioning

confidence: 99%

Vertically Aligned n-Type Silicon Nanowire Array as a Free-Standing Anode for Lithium-Ion Batteries

et al. 2021

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“…Numerous studies have been conducted to solve the abovementioned issues. These include reducing the size of the Si particles to prevent generation of stress, , doping Si with impurities, such as boron and phosphorous, to suppress the Si-to-Li 15 Si 4 phase transition, and/or increasing its electrical conductivity, ,− and preparing lithium silicides to decrease the relative volume change in Si during charge–discharge cycles . Other approaches involve coating Si with conductive materials to lower the electrical resistivity , or synthesizing Si-based alloys to enhance the stability of the electrode structure during cycling. − Moreover, film-forming additives or ionic liquid electrolytes have been utilized for the construction of an optimal solid–electrolyte interphase. − Lastly, composites have been prepared to improve the mechanical properties …”

Section: Introductionmentioning

confidence: 99%

Effect of Element Substitution on Electrochemical Performance of Silicide/Si Composite Electrodes for Lithium-Ion Batteries

Domi

Usui

Nakabayashi

et al. 2020

ACS Appl. Energy Mater.

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Si is a promising candidate for application as an active material for negative electrodes in lithium-ion batteries. However, its practical use is limited due to the large change in Si volume during cycling. It was previously reported that binary silicide/Si composite electrodes exhibit better electrochemical performance than a Si-alone electrode. Silicide has been found to have several properties, including mechanical characteristics, low electrical resistivity, moderate reactivity with Li + , and high thermodynamic stability, which alleviate the stress from Si. To improve the performance of the composite electrodes, it is essential to carefully modify these properties by element substitution. In this study, a Cr 1−x V x Si 2 /Si composite was synthesized and its electrochemical performance was investigated. The changes in the properties of CrSi 2 after V substitution were also evaluated. The Cr 0.5 V 0.5 Si 2 /Si electrode exhibited a longer cycle life than the CrSi 2 and VSi 2 electrodes, indicating that the element substitution contributed to an improvement in cycle life. Due to a larger crystal lattice arising from VSi 2 and a smaller charge repulsion resulting from CrSi 2 , Li was found to easily diffuse into Cr 0.5 V 0.5 Si 2 . Hence, Li could readily move between the Si phases via the Cr 0.5 V 0.5 Si 2 phase. It was speculated that the homogeneous storage of Li in the Si phase resulted in no local stress and suppression of severe electrode disintegration. Overall, it was concluded that the Cr 0.5 V 0.5 Si 2 /Si electrode exhibited a longer cycle life.

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“…Although the optimization of the conductive additive, , binder, , powder size, , and electrode structure , is effective in improving the electrical conductivity of the entire electrode and accommodating volume expansion and contraction for achieving a long-cycle life, it is difficult to enhance the Li + diffusion coefficient and the electrical conductivity of Si as a bare material. As a typical method of improving its properties, doping of impurity into Si has been considered: − O’Dwyer et al reported that a higher current response was observed during cyclic voltammetry using n-type Si with the B dopant compared with that of p-type Si with the As dopant (doping density: 1.2–7.4 × 10 19 atoms cm –3 and 240–1480 ppm) . Greeley and Gewirth et al studied the energetics and kinetics of Li insertion into p-type and n-type crystalline Si using the B-doped and P-doped Si wafers with two crystallographic faces of (100) and (111) .…”

Section: Introductionmentioning

confidence: 99%

Dopant Effect on Lithiation/Delithiation of Highly Crystalline Silicon Synthesized Using the Czochralski Process

Shimizu

Kimoto

Kawai

et al. 2021

ACS Appl. Energy Mater.

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The huge theoretical capacity of 3580 mA h g–1 based on alloying reactions with Li strongly motivates the use of Si as a negative electrode material in the construction of Li-ion batteries with high energy density. However, its poor electrical conductivity and low Li+ diffusion coefficients as well as the significant volume change in Si during lithiation/delithiation are the bottlenecks for practical application. As one typical method for improving their properties, impurity doping into Si has been considered; however, many of them were amorphous or the impurity concentration against depth direction was not homogeneous, which has complicated the understanding of the effect of impurities on the lithiation/delithiation of Si. In this work, we synthesized Si ingots heavily doped with P (2000 ppm) or B (1600 ppm) as a dopant using the Czochralski method, which overcomes the above issues. In galvanostatic charge/discharge conditions using slurry-type electrodes, the electrical conductivity increased by 108 times compared to that of the undoped Si. The P- (0.119 V) and B-doping (0.126 V) allowed the Li-insertion reaction to occur at higher potentials compared to undoped Si (0.113 V). Even when using 5 vol % fluoroethylene carbonate as a film-forming additive and suppressing an excess volume change in Si during lithiation by the limitation of a charge capacity of 1000 mA h g–1, the undoped Si showed poor cyclability. In contrast, the optimized condition maximized the effect of the improved electrical conductivity and the mechanical properties and thereby enabled the P-doped Si to achieve an excellent performance for more than 300 cycles. Considering the softer properties and the greater fracture toughness of the P-doped Si (1514 HV and P–Si: 363.6 kJ mol–1) than those of B-doped Si (1787 HV and B–Si: 317 ± 12 kJ mol–1), the mechanical properties and fracture toughness, rather than electrical conductivity, make a significant contribution.

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Reduced Silicon Fragmentation in Lithium Ion Battery Anodes Using Electronic Doping Strategies

Cited by 21 publications

References 64 publications

Vertically Aligned n-Type Silicon Nanowire Array as a Free-Standing Anode for Lithium-Ion Batteries

Vertically Aligned n-Type Silicon Nanowire Array as a Free-Standing Anode for Lithium-Ion Batteries

Effect of Element Substitution on Electrochemical Performance of Silicide/Si Composite Electrodes for Lithium-Ion Batteries

Dopant Effect on Lithiation/Delithiation of Highly Crystalline Silicon Synthesized Using the Czochralski Process

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