Stress-Tolerant Nanoporous Germanium Nanofibers for Long Cycle Life Lithium Storage with High Structural Stability

Abstract

Nanowires (NWs) synthesized via chemical vapor deposition (CVD) have demonstrated significant improvement in lithium storage performance along with their outstanding accommodation of large volume changes during the charge/discharge process. Nevertheless, NW electrodes have been confined to the research level due to the lack of scalability and severe side reactions by their high surface area. Here, we present nanoporous Ge nanofibers (NPGeNFs) having moderate nanoporosity via a combination of simple electrospinning and a low-energetic zincothermic reduction reaction. In contrast with the CVD-assisted NW growth, our method provides high tunability of macro/microscopic morphologies such as a porosity, length, and diameter of the nanoscale 1D structures. Significantly, the customized NPGeNFs showed a highly suppressed volume expansion of less than 15% (for electrodes) after full lithation and excellent durability with high lithium storage performance over 500 cycles. Our approach offers effective 1D nanostructuring with highly customized geometries and can be extended to other applications including optoelectronics, catalysis, and energy conversion.

In situ electrochemical conversion of CO 2 in molten salts to advanced energy materials with reduced carbon emissions

“…S10D), and the film remains closely attached onto the Cu foil substrate (inset in fig. S10D) after 350 cycles at 500 mA g −1 , revealing high stability of the Ge@CNT electrode (17,34). The capacity based on Ge content is high up to 2053 mAh g −1 at 200 mA g −1 , suggesting a very high utilization efficiency of Ge atoms in Ge@CNT (18).…”

“…The performance of the Ge@CNTs for lithium storage is comparable to that of similar Ge/C composites in literatures (6, 17-21, 34, 37-39). The enhanced lithium storage capability of Ge@CNTs is mainly attributed to the unique structural and compositional merits (18,20,34,38). To be specific, the encapsulated Ge core can provide high capacities for Li + storage, while the CNT shell with large free space can buffer volume variation during lithiation/delithiation process to ensure excellent structure stability and mechanical integrity (18,20,21).…”

Uniformly Confined Germanium Quantum Dots in 3D Ordered Porous Carbon Framework for High‐Performance Li‐ion Battery

“…To address these issues, diverse advanced Ge nanostructures such as nanoparticles, [ 2d ] nanotubes, [ 6 ] nanowires, [ 7 ] nanofibers, [ 8 ] and nano‐porous particles, [ 4,9 ] have been investigated during the past decades. These nanostructures can effectively increase the specific capacity and extend the cycle lifetime, which are mainly attributed to their short Li‐ion diffusion distance and high interfacial contact area with organic electrolytes.…”

Atmospheric pressure metal organic chemical vapor deposition of thin germanium films

“…With the development of new germanium-based functional materials for energy conversion [1], for lithium-ion batteries [2][3][4][5][6][7][8][9][10][11] or as photocatalysts [12], the synthesis of germanium nanorods, [13] nanowires [14][15][16][17][18][19], and nanoparticles [20][21][22][23][24][25][26] has significantly gained in importance. In addition, germanium thinfilms are of great interest with regard to potential applications, e.g., photovoltaics [27], plasmonics [28], optoelectronics [29], electronics [30][31][32], optics Therefore, diverse methods for the fabrication of germanium films such as thin-film transfer [38], AFM nanolithography [39], or laser photolysis techniques [40,41] were reported, and in most cases, the deposition of films is addressed via the gas phase, e.g., atomic layer deposition (ALD) [42], physical vapor deposition (PVD) [31,43,44], or metal organic chemical vapor deposition (MOCVD) [45][46][47]…”