Naturally Rolled‐Up C/Si/C Trilayer Nanomembranes as Stable Anodes for Lithium‐Ion Batteries with Remarkable Cycling Performance

Abstract

Lithium-ion batteries (LIBs) have attracted considerable interest because of their wide range of environmentally friendly applications, such as portable electronics, electric vehicles (EVs), and hybrid electric vehicles (HEVs). [1][2][3][4][5] For the next generation of LIBs with high energy and high power density, improvements on currently used electrode materials are urgently needed. [6][7][8][9][10] Among various anode materials, Si has been extensively studied owing to its highest theoretical capacity (4200 mA h g À1 ), abundance in nature, low cost, and nontoxicity. However, Si-based anodes are notoriously plagued by poor capacity retention resulting from large volume changes during alloy/de-alloy processes (400 %). The intrinsic strain generated during such expansion and contraction easily leads to electrode pulverization and capacity fading. Thus, it is a big challenge to achieve both excellent cyclability and enhanced capacity of Si-based anode materials.Significant efforts have been devoted to circumvent this issue caused by the volume change of silicon. [11][12][13][14][15] Recently, a number of Si nanostructures, including nanoparticles, [15,16] nanowires/nanorods, [17][18][19] nanotubes, [20] and porous nanostructures [21,22] as well as their composites, [23] have been fabricated to achieve improved cycling performance.Among them, tubular structures, with extra interior space for electron and ion transport, as well as for accommodating volume changes, are one of the most attractive and promising configurations for LIBs. However, such anode materials are still far from commercialization, and new strategies for the synthesis of novel structures with superior cycling performance and stability are still much sought-after.Herein, we report a new tubular configuration made from naturally rolled-up C/Si/C trilayer nanomembranes, which exhibits a highly reversible capacity of approximately 2000 mA h g À1 at 50 mA g À1 , and approximately 100 % capacity retention at 500 mA g À1 after 300 cycles. The sandwich-structured C/Si/C composites, with moderate kinetic properties toward Li + ion and electron transport, are of the highest quality. The excellent cycling performance is related to the thin-film effect combined with carbon coating, which play a structural buffering role in minimizing the mechanical stress induced by the volume change of Si. The energy reduction in C/Si/C trilayer nanomembranes after rolling up into multi-winding microtubes results in a significantly reduced intrinsic strain, which can improve capacity and cycling performance. This synthetic process could be compatible with existing industrial sputtering deposition processes as well as roll-to-roll thin-film fabrication technology.The strategy for the self-release of C/Si/C trilayer nanomembranes using rolled-up nanotechnology [24] to form multilayer C/Si/C microtubes is shown in Scheme 1. First, a sacrificial layer (red color, photoresist ARP 3510) was deposited on top of the Si substrates by spin-coating, then trilayer C/Si/C (10/40/10 nm, ...

Si nanoparticles adhering to a nitrogen-rich porous carbon framework and its application as a lithium-ion battery anode material

“…Then after dispersing the Si nanoparticles into the nitrogen-rich carbon matrix, the cycling performance of the obtained Si/C composite has been improved a lot by contrast with the pure Si nanoparticles. 41,42 Moreover, the charge/discharge curves at different rates have also been presented to exhibit the rate behaviors of the Si/porous C composite (Fig. The rapid capacity fading of the Si/C composite is due to the nitrogen-rich carbon matrix with nonporous structure which cannot effectively buffer the large volume change of Si nanoparticles during the Li-ion insertion/extraction process.…”

Control over large-volume changes of lithium battery anodes via active–inactive metal alloy embedded in porous carbon

“…As the organic electrolytes decompose at the working potential of o0.5 V vs. Li + /Li and forms a thin SEI layer [13,14]. But the expansion and contraction of Sn during alloying and de-alloying causes deformation and breakage of the SEI layer, respectively [11,15,16]. As a result, formation of new SEI on freshly exposed Sn surface eventually block Li + transport via accumulation within SEI and causes poor Coulombic efficiency (CE) of cell [10,17].…”

Heading towards novel superior silicon-based lithium-ion batteries: ultrasmall nanoclusters top-down dispersed over synthetic graphite flakes as binary hybrid anodes

“…In the first cycle, both specimens exhibited a typical charging (lithiation) platform of silicon at ~0.1 V. Co-dominated by both SiUPs and graphite flakes, the lithiation process in the first cycle curve showed a slight protrusion from 0.8V to 0.4V, which might be caused by the gradual formation of stable SEI. [4][5][6][7][8][9][10][11][12][13][14][15] The rate performances of TD-SiUPs-31 and m-SiUPs at a series of increased current densities of 0.8, 1.6, 2.4, and 3.2 A g -1 are compared in Figure 5E. In the first cathodic scan, the branch between 0.5 to 1.2V was attributed to the intensive interface reaction between the active materials and the electrolyte, leading to the formation of SEI layer.…”