Graphene reinforced carbon nanofiber engineering enhances Li storage performances of germanium oxide

Abstract

In the GeO2/nanocable, amorphous carbon and graphene spontaneously construct a nanocable structure, graphene “core” promises the good electrical conductivity while the amorphous carbon “shell” guarantees the fast Li ions diffusion.

Fluorine-Doped GeO2@C Composite with Abundant Oxygen Vacancies for High-Capacity Lithium-Ion Batteries

“…The capacity of the F-GeO 2 @C electrode remains 1300 mAh g –1 after 100 cycles with a Coulombic efficiency (CE) of 99.3%, which is much higher than that of the GeO 2 @C electrode (626 mAh g –1 ). F-GeO 2 @C also shows higher energy density than most previously reported carbonaceous GeO 2 composites, − which may be attributed to the effect of F-doping on the GeO 2 -based anodes. Figure d shows the reversible specific capacities of the F-GeO 2 @C electrode at a higher current density of 5 A g –1 .…”

“…When it was gradually restored to 0.5 A g –1 , the reversible capacity of the electrode is restored to 1230 mAh g –1 , exhibiting the stability of the electrode (Figure S5). As shown in Figure f, it is worth mentioning that F-GeO 2 @C shows great improvement of the rate performance, compared to most GeO 2 -based anodes reported in recent studies. ,− Furthermore, to evaluate the volumetric capacities, the tap density of F-GeO 2 @C was determined according to the testing method in other references . The tap density of the F-GeO 2 @C powder is 1.25 g cm –3 , which is higher than that of commercially used graphite (1.0 g cm –3 ).…”

“…Considerable efforts, such as the construction of the GeO 2 nanostructure and the integration of the carbon matrix to form hybrid composites, have been proposed to improve the electrochemical performance. − The various types of the carbon matrix not only enhance the electrical conductivity of the electrode but also accommodate the volume expansion and improve structural stability during cycling. − The capacities and cycling performance have been increased for these nanosized carbonaceous GeO 2 composites. However, because of irreversible generation of Li 2 O, low initial Coulombic efficiencies (ICEs) were often achieved in these GeO 2 -based anodes. − The addition of catalysts (Fe, Ge, etc.) to GeO 2 -based composites can activate effective reduction of partial Li 2 O.…”

State-of-the-Art of Solid-State Electrolytes on the Road Map of Solid-State Lithium Metal Batteries for E-Mobility

“…The application fields of LIBs also have been expanded from electronics devices to electric vehicles and grid energy storage systems . This is because LIBs offer a higher operating voltage and energy density, longer cycle life, and lower self-discharge rate compared to many other types of batteries. ,, Although LIBs have undergone many evolutions from the conventional LIBs to the solid-state LIBs as shown in Figure and almost approached their limits of theoretical specific capacity, there are still bottlenecks that severely restrict the practicality and feasibility of LIBs to satisfy the growing demand for more advanced energy storage technologies, especially in the high performance and large scale applications in our modern society. ,,,, The current existing LIBs have limited energy storage capacity as the graphite anode materials have a relatively low specific capacity of 372 mAh g –1 . ,, Moreover, the LIBs have a low lithium intercalation potential between the graphite anode and lithium transition metal oxide (LTMO) cathode, hence raising the safety issues . This therefore signifies the need to develop and research on novel anode and cathode materials to further improve the energy density and safety of the lithium-based batteries to meet the needs of sustainable development for energy storage technology and safe production.…”

Centrifugally Spun Binder-Free N, S-Doped Ge@PCNF Anodes for Li-Ion and Na-Ion Batteries

“…Considering increasing demand and high requirements of new applications including EVs, anode materials with high capacity and low-cost preparation methods need to be developed. − Germanium (Ge) is a promising anode material because of its fast Li + diffusivity, good electronic conductivity (small band gap of 0.6 eV), and high theoretical capacity (1600 mAh g –1 in LIBs and 369 mAh/g in SIBs). However, the large volume expansion, pulverization, and electrical disconnects between the active materials and the electrode framework lead to poor cycling performance. , Designing carbon composite anode materials could confine the volume expansion of Ge and maintains the good integrity of the anode which could lead to long cycle life.…”