In Situ Confined Co₅Ge₃ Alloy Nanoparticles in Nitrogen-Doped Carbon Nanotubes for Boosting Lithium Storage

Abstract

Ge-based materials have garnered much attention in lithium-ion batteries (LIBs) for their high theoretical capacity, but these materials suffer from huge volume changes and serious pulverization, which cause insufficient lithium storage performance. Herein, a composite composed of Co 5 Ge 3 -and nitrogen-doped carbon nanotube (Co 5 Ge 3 /N-CNT) was successfully synthesized using ZIF-67 and GeO 2 as precursors. There are interactions between the Co 5 Ge 3 alloy nanoparticles and carbon nanotubes in the growth process, in which the Co 5 Ge 3 alloy nanoparticles were confined in situ in N-CNTs and the in situ growth of N-CNTs was boosted in the existence of the Co 5 Ge 3 catalyst. Density functional theory calculations revealed that the electronic conductivity of the Co 5 Ge 3 alloy is much higher than that of Ge and the Li + interaction energy of the former is lower than that of the latter. In addition, the interconnected carbon nanotubes not only offer Li + diffusion pathways and electronic networks but also increase electronic conductivity. Importantly, carbon nanotubes and Co metal have a synergistic effect of buffering volume charge of Ge in the process of Li + intercalation/deintercalation. As expected, the Co 5 Ge 3 /N-CNT composite demonstrated a high reversible capacity of 853.7 mA h g −1 at 2 A g −1 after 1500 cycles and attractive rate performance of up to 10 A g −1 .

Laser-generated high entropy metallic glass nanoparticles as bifunctional electrocatalysts

“…7(c) and 7(d)) as it is highly relevant in energy conversion systems such as fuel cells [100]. In contrast to the OER activities, here the Cr 17 [101]. The highest ORR activity was obtained for the PtCo sample having Pt:Co ratio 1:2 with a potential of 870 mV.…”

“…Nonetheless, we will use the expression HEA throughout this manuscript as it is deeply rooted in the discourse. It is well established that a rational design of HEA composition allows controlling their physicochemical properties at the nanoscale and performance, e.g., in catalysis [12,15,16] and energy storage [17][18][19]. Due to these unique interactions of distinct neighboring metal atoms [2], HEA NPs are discussed and developed as very promising candidates to replace established but scarce and expensive noble metals in catalytic reactions such as oxygen evolution [20][21][22][23][24], oxygen reduction [2,25,26], methanol oxidation [27][28][29], CO 2 reduction [30,31] and hydrogen evolution [22,32,33].…”

MOF-Derived CoS2/N-Doped Carbon Composite to Induce Short-Chain Sulfur Molecule Generation for Enhanced Sodium–Sulfur Battery Performance

“…Room-temperature sodium–sulfur (Na−S) batteries have emerged as an appealing choice for large-scale energy storage applications due to the natural abundance and low toxicity of sulfur and, more importantly, a two-electron transfer per sulfur atom, which delivers 6 times the energy density of conventional Li-ion batteries. − Still, for practical applications, several key issues of Na–S batteries must be addressed. Poor conductivity of sulfur results in sluggish electrochemical reaction kinetics and its low utilization, while a large volume expansion (≈170%) of sulfur during cycling may seriously affect the cathode stability. − Perhaps, more severely, the “shuttle effect” of soluble sodium polysulfides (Na 2 S n , n = 4–8) in liquid electrolytes results in a loss of active sulfur, low Coulombic efficiency, and capacity fading of Na–S batteries. − …”

Ternary AlGexP alloy compounds for high capacity and rate capability of lithium-ion battery anodes

“…To facilitate charge storage kinetics, various nanostructures of Ge-based materials such as nanotubes, hollow nanoboxes, and quantum dots have been developed. 3,[5][6][7][8][9][10][11][12] However, nanostructured Ge-based anodes still suffer from relatively low initial Coulombic efficiency (ICE) brought by side reactions on the large surface area and low mass loading which makes it difficult to fabricate high capacity dense electrodes. 13 Apart from high preparation cost, their insufficient subsequent Coulombic efficiencies also remain a critical challenge to hinder their application in battery full cells, of which the lithium from the cathode is limited.…”