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a) Areal capacity of Li||Si/CuSi for different Si loadings (0.98–1.37 mg cm⁻²). b) Effect of C‐rate on both areal capacity (0.1–5C) and GCD profile for Li||Si/CuSi 1.37 mg cm⁻².
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High loading (>1.6 mg cm⁻²) of Si nanowires (NWs) is achieved by seeding the growth from a dense array of Cu15Si4 NWs using tin seeds. A one‐pot synthetic approach involves the direct growth of CuSi NWs on Cu foil that acts as a textured surface for Sn adhesion and Si NW nucleation. The high achievable Si NW loading is enabled by the high surface a...
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Metallic copper is widely used as a current collector (CC) for the negative
electrode of lithium-ion batteries (LIBs) due to its high electrical conductivity and
electrochemical stability. However, the large volume density of commercial copper foil
(~8.9 g cm-3) limits the increase of energy density of the battery. Here, copper-coated
porous polyim...
Citations
... The nano-sized Si disperses the structural strain during the lithiation process, thereby maintaining the structural integrity of the electrode [18]. Based on this strategy, Si materials with various nanostructures, such as nanoparticles [19,20], nanowires [21,22], two dimensional nanomembranes [23,24], and three dimensional nanoporous Si [25,26] have been proposed. For instance, Mai et al. [20] coated a compact sub-nanometer interfacial SiOx/C composite layer ($20 nm thick) on Si nanoparticles. ...
... Beyond gold catalysts, Storan et al. thermally evaporated tin catalysts onto the carbon cloth and grew SiNWs using phenylsilane as a precursor ( Fig. 4(d)) [108]. Collins et al. also used tin as the catalyst to decorate pre-formed Cu 15 Si 4 nanowires with SiNWs at 460 °C, which could increase the capacity of LIBs [109]. ...
The integration of nanowires onto electrode surfaces marks a significant advancement over traditional electrode materials, conferring upon nanowire-modified electrodes a vast array of applications within electrochemical and electrophysical domains. The nanowires used for electrode modification can be catalogized into two distinct types: anchored nanowires and free-standing nanowires. A critical advantage of anchored nanowires lies in their enhanced electrical connectivity with the substrate, which reduces electrode resistance and facilitates charge transport. Furthermore, the anchorage of nanowires onto electrodes provides additional mechanical support, bolstering the structural stability of the nanowire assembly. Here, we review the development of anchored nanowires designed for applications in energy storage, electrocatalysis, and electric field treatment (EFT) over the past decade. We focus on the synthesis and modification strategies employed for anchored nanowires, culminating in the evaluation of these fabrication and enhancement techniques. Through this analysis, we aim to furnish comprehensive insights into the preparation of anchored nanowires, guiding the selection of appropriate fabrication processes and subsequent functional modifications.
... After 200 cycles, an active layer of about 6 µm thickness is formed on the substrate surface, and the skeleton is still completely covered Ionics (Fig. S10c, d). This reflects a strong adhesion between the Si NWs and the Ni x Si y [48], giving the Ni x Si y @Si NWs electrode high structural stability. ...
Silicon, with its many advantages, is gaining attention in the field of lithium-ion battery anode materials. However, severe volume swelling, poor conductivity, and slow Li⁺ diffusion kinetics are major obstacles to enhancing the electrochemical properties of silicon anodes. One-dimensional silicon nanowires with a high aspect ratio can effectively ameliorate these issues, while the complexity of the synthesis method limits its development. Here, a three-dimensional flexible electrode of binary-phase Ni-silicide foam loaded with silicon nanowires (NixSiy@Si NWs) was constructed in two simple steps: preparation of metal catalyst nanoparticles using a chemical plating approach and production of silicon nanowires by the supercritical fluid-liquid–solid mechanism. Benefiting from the excellent anchoring ability and superior electrical conductivity of NixSiy as well as the extra space and favorable Li⁺ and electrolyte diffusion paths provided by the Si NWs network, the as-obtained anode exhibits a high initial Coulombic efficiency of 77% at 0.5 A g⁻¹, excellent cycling performance (a reversible capacity of 1238 mAh g⁻¹ after 200 cycles) and outstanding rate capability (2675, 2497, 2164, 1740, and 1222 mAh g⁻¹ at 0.5, 1, 2, 4, and 8 A g⁻¹, respectively).
... Besides, the voids among Si nanomaterials can buffer their volumetric expansion during cycling. Therefore, the lithium storage properties of Si are enhanced [14][15][16][17]. ...
Si has been considered as an appealing anode material for high-performance lithium-ion batteries due to its high theoretical capacity. However, the large volume variation limits its practical application. Herein, a binder-, conductive additive- and current collector-free Si/reduced graphene oxide film has been constructed via a simple thermal-reduction method. In the film, Si nanoparticles are encapsulated by reduced graphene oxide, which can accommodate the volume change of Si during cycling efficiently. When utilized as a negative electrode, the Si/reduced graphene oxide film has displayed a high reversible capacity of 1733.4 mAh g⁻¹ after 50 cycles at 200 mA g⁻¹. Importantly, the electrochemical impedance spectroscopy results suggest that the composite film possesses more efficient electrochemical reaction kinetics. The strategy reported in this work may supply a facile preparation route for other metal or metal oxides/reduced graphene oxide films.
... [3,[7][8][9][10][11][12][13][14][15][16] This has led to silicides finding applications in diverse technological areas, including nanoelectronics (as electrical contacts, gates, and local interconnects), spintronics, optoelectronics, thermoelectrics, catalysis, and batteries. [15,[17][18][19][20][21][22][23][24][25][26][27] Metal silicides play a significant role in improving battery performance, either as active (Mg-Si, Ca-Si, Li-Si) [28][29][30] or inactive components (Cu-Si, Ni-Si, Ti-Si, Fe-Si) [31,32] Apart from their utility as interconnects and field emitters, copper-rich silicides have been utilized as inactive supports to improve the electrochemical stability of alloying anodes (Si, Sb, Sn, Bi, Ge, and P) for renewable alkali metal-ion batteries due to their low cost and compatibility in battery chemistry. [21,[32][33][34][35][36] Alloying anodes capable of delivering high specific capacity at low working voltage anodes are promising active materials across alkali metal-ion batteries. ...
... [15,[17][18][19][20][21][22][23][24][25][26][27] Metal silicides play a significant role in improving battery performance, either as active (Mg-Si, Ca-Si, Li-Si) [28][29][30] or inactive components (Cu-Si, Ni-Si, Ti-Si, Fe-Si) [31,32] Apart from their utility as interconnects and field emitters, copper-rich silicides have been utilized as inactive supports to improve the electrochemical stability of alloying anodes (Si, Sb, Sn, Bi, Ge, and P) for renewable alkali metal-ion batteries due to their low cost and compatibility in battery chemistry. [21,[32][33][34][35][36] Alloying anodes capable of delivering high specific capacity at low working voltage anodes are promising active materials across alkali metal-ion batteries. [37][38][39] Despite this benefit, the volume expansion of alloying anodes during repeated cycling leads to pulverization and SEI layer instability. ...
... Conventionally, transition metal silicides are synthesized by four methods: i) silicidation of pre-formed Si NWs, ii) decomposition of Si on a metal substrate, iii) reaction of metal with a Si substrate, and iv) deposition of both metal and Si. [2][3][4]9,13,32,[49][50][51][52][53][54][55][56][57] A large range of transition metal silicide NWs with different crystal phases has been synthesized using these techniques. [23,[58][59][60][61][62][63][64][65][66][67][68][69] However, the controlled synthesis and reproducibility of metal silicide NWs is challenging due to the complex metal-Si phase diagrams, with the possibility of numerous metal silicide stoichiometries. ...
Metal silicide thin films and nanostructures typically employed in electronics have recently gained significant attention in battery technology, where they are used as active or inactive materials. However, unlike thin films, the science behind the evolution of silicide nanostructures, especially 1D nanowires (NWs), is a key missing aspect. CuxSiy nanostructures synthesized by solvent vapor growth technique are studied as a model system to gain insights into metal silicide formation. The temperature‐dependent phase evolution of CuxSiy structures proceeds from Cu>Cu0.83Si0.17>Cu5Si>Cu15Si4. The role of Cu diffusion kinetics on the morphological progression of Cu silicides is studied, revealing that the growth of 1D metal silicide NWs proceeds through an in situ formed, Cu seed‐mediated, self‐catalytic process. The different CuxSiy morphologies synthesized are utilized as structured current collectors for K‐ion battery anodes. Sb deposited by thermal evaporation upon Cu15Si4 tripod NWs and cube architectures exhibit reversible alloying capacities of 477.3 and 477.6 mAh g⁻¹ at a C/5 rate. Furthermore, Sb deposited Cu15Si4 tripod NWs anode tested in Li‐ion and Na‐ion batteries demonstrate reversible capacities of ≈518 and 495 mAh g⁻¹.
... 20 The nanostructures have demonstrated good adhesion and stability during cycling, and various synthesis methods have been explored. [21][22][23][24] Copper silicide nanostructures also have potential applications in microelectronic devices. [25][26][27][28][29] Finally, copper is a widely used catalyst, either pristine or as an alloy with other elements. ...
A copper-based catalyst CuxSi (3 < x < 5) was prepared using chemical vapor deposition (CVD) of butylsilane (BuSiH3) on copper substrates. By varying the precursor flow, we obtained two catalyst variants, one with and one without a SiCx shell. Both variants exhibited large specific areas, owing to the presence of grown nanostructures such as nanoplatelets, nanowires, nanoribbons, and microwires. Remarkably, the catalytic performance of both variants remained stable even after 720 hours of continuous operation. The porous and thick catalyst layer (over a hundred micrometers) on the substrate significantly increased the residence time of intermediates during the electrochemical CO2 reduction reactions (eCO2RR). We observed a high selectivity towards ethanol (∼79%) in neutral CO2-saturated electrolytes and a high selectivity towards acetic acid (∼72%) in alkaline electrolytes. Importantly, the ratio between generated ethanol and acetate could be shifted by adjusting the pH and applied potential. This work thus establishes copper silicides as robust and promising electrocatalysts for selective CO2 conversion to high-value multi-carbon products.
... Nowadays, Si-Cu nanowires, as a special kind of 1D silicon/metal nanocomposite materials that are utilized in enhancing silicon-based LIB-anode performance, have been receiving more and more awareness and being widely investigated in depth. Recently, Collins et al. have developed a one-pot synthesis strategy [30], as a unique manufacturing method to enhance the efficiency of a chemical reaction whereby a reactant is subjected to successive chemical reactions in just one reactor, to lead Si-Cu nanowires directly growing on copper foils. Tin was introduced to grow in compact alignment of Cu 15Si4 intermetallic compound nanowires during the synthesizing process, so as to promote superior galvanic capacity and load of 1D silicon-based nanocomposite materials. ...
... Hence, the strategy of combining silicon nanostructure design and silicon-based composite is quite effective and practical, implying a bright research perspective and extraordinary application potential. Figure 2. Cyclic charging/discharging areal capacity and coulombic efficiency of silicon/silicon copper intermetallic compounds for silicon nanowire loads of a) 0.65 mg/cm2, b) 1.02 mg/cm2, c) 1.31 mg/cm2, and d) 1.60 mg/cm2 [30]. ...
With the development and wide-use of lithium-ion batteries, silicon, due to its high theoretical specific capacity and superior fast charging performance, is being studied intensively and extensively as a new generation of anode materials for the batteries. However, challenges of large volume expansion and poor electrical conductivity has limited the performance and commercial applications of silicon-based anode materials, which is led by pulverization of silicon particles, low initial coulombic efficiency, and unstable solid-electrolyte interphase films. To solve the issues, five main strategies have been proposed correspondingly: nanostructured silicon, silicon-based composites, new binders, new electrolyte additives, and pre-lithiation. Among them, the approaches of nanostructured silicon (0D, 1D, 2D) and silicon-based composites (silicon/carbon, silicon/metal, silicon/transition metal oxide) are practical and effective, thus being explored in depth as the focus of many researches, respectively. After summarizing and analyzing the research progress in enhancing the performance of silicon-based anode materials, it is inferred that the advantages of nanostructured silicon are complementary with those of silicon-based composite materials. Silicon-based nanocomposite materials, as the combination of nanostructured silicon and silicon-based composites, are comparatively more significant and useful than either of those. Therefore, the trend of combining the two strategies to achieve a better improvement is unstoppable.
... 32,33 More recently explored is the use of Cu-silicide NW networks as growth substrates for high-density NWs. 34,35 Integrating this substrates grown NW into traditional battery configurations is still challenging, especially since the inactive nanostructured network adds dead mass to the final device. ...
Here, we report the solution phase synthesis of axial heterostructure Si and Ge (hSG) nanowires (NWs). The NWs were grown in a high boiling point solvent from a low-cost Sn powder to achieve a powder form product which represents an attractive route from lab-scale to commercial application. Slurry processed anodes of the NWs were investigated in half-cell (versus Li-foil) and full-cell (versus NMC811) configurations of a lithium ion battery (LIB). The hSG NW anodes yielded capacities of 1040 mA h g⁻¹ after 150 cycles which corresponds to a 2.8 times increase compared to a standard graphite (372 mA h g⁻¹) anode. Given the impressive specific and areal capacities of the hSG anodes, a full-cell test against a high areal capacity NMC811 cathode was examined. In full-cell configuration, use of the hSG anode resulted in a massive anode mass reduction of 50.7% compared to a standard graphite anode. The structural evolution of the hSG NW anodes into an alloyed SiGe porous mesh network was also investigated using STEM, EDX and Raman spectroscopy as a function of cycle number to fully elucidate the lithiation/delithiation mechanism of the promising anode material.
... The maximum theoretical performance of silicon electrodes in aprotic LIBs is about 4212 mAhg −1 at high temperatures (lithiation to Li 4.4 Si) and 3579 mAhg −1 at roomtemperature (lithiation to Li 15 Si 4 ) to be compared to 372 mAhg −1 of graphite [10]. In real cells, due to kinetic hinderance and the consequent overpotentials, figures above 2500-3000 mAhg −1 can only be achieved by a careful selection and optimization of nanostructures as well as by tailoring the Si surface by electrode additives, particle coatings or grafting supramolecular aggregates on the electrode film [7,[11][12][13][14][15][16][17][18]. In fact, nano-structuring, electrode formulation and the electrolyte composition strongly impact on the reversibility of the lithiation/de-lithiation of silicon electrodes [3,10]. ...
... Carbon signals in the uncycled sample can be due to the synthesis residues of the carbon-containing precursor (squalene), possibly also inducing the local formation of SiC, as also suggested by the shoulder detected at about 790 cm −1 [56]. It is important to mention that the crystallinity of the pristine silicon sample has been already demonstrated by some of us by X-ray diffraction as reported in ref. [15]. ...
The morphological changes of Si nanowires (Si NWs) cycled in 1:1 ethylene–carbonate (EC)/diethyl–carbonate (DEC) with or without different additives, fluoroethylene carbonate (FEC) or vinylene carbonate (VC), as well as the composition of the deposited solid–electrolyte interphase layer, are investigated by a combination of experimental microscopic and spectroscopic techniques. Scanning electron microscopy and optical spectroscopy highlight that the NW morphology is better preserved in samples cycled in the presence of FEC and VC additives compared to the additive-free electrolyte. However, only the use of FEC is capable of slightly mitigating the amorphization of silicon upon cycling. The solid electrolyte interphase (SEI) formed over the Si NWs cycled in the additive-free electrolyte is richer in organic and inorganic carbonates compared to the SEI grown in the presence of the VC and FEC additives. Furthermore, both additives are able to remarkably limit the degradation of the LiPF6 salt. Overall, the use of the FEC-additive in the carbonate-based electrolyte promotes both morphological and structural resilience of the Si NWs upon cycling thanks to the optimal composition of the SEI layer.
... [39] This phenomenon is more visible when voltage is lower than 0.3 V, especially for this material. Moreover, major lithiation peaks at 1.1, 0.53, 0.25, 0.13, and near 0.01 V corresponds to the mixture phase transition of SnO y and SiO x , [40,41] formation of Li x Sn through the Sn with Li + and insertion of Li + into C layer, [42,43] the alloying process of Li-Si, [44,45] mixture alloying reactive of Li-Sn and Li-Si, [46][47][48] the mixture of Si-Li alloys and Lithium-insert C layer, [49,50] respectively. Noteworthy, the lithiation peak at 0.25 V, which appears in the second cathodic scan and presents in all subsequent cycles, can give evidence that Si exists in SnO y @C/ SiO x -50 and is activated by impregnation of electrolyte with the battery cycling gradually. ...
To break the stereotype that silica can only be reduced via a magnesiothermic and aluminothermic method at low‐temperature condition, the novel strategy for converting silica to SiOx using disproportionation effect of SnO generated via low‐temperature pyrolysis coreduction reaction between SnO2 and rice husk is proposed, without any raw materials waste and environmental hazards. After the low‐temperature pyrolysis reaction, SnOy@C/SiOx composites with unique structure (Sn/SnO2 dispersed on the surface and within pores of biochar as well as SiOx residing in the interior) are obtained due to the exclusive biological properties of rice husk. Such unique structural features render SnOy@C/SiOx composites with an excellent talent for repairing the damaged structure and the highly electrochemical storage ability (530.8 mAh g⁻¹ at 10 A g⁻¹ after 7500 cycles). Furthermore, assembled LiFePO4||SnOy‐50@C/SiOx full cell displays a high discharge capacity of 463.7 mAh g⁻¹ after 100 cycles at 0.2 A g⁻¹. The Li⁺ transport mechanism is revealed by density functional theory calculations. This work provides references and ideas for green, efficient, and high‐value to reduce SiO2, especially in biomass, which also avoids the waste of raw materials in the production process, and becomes an essential step in sustainable development.
