A Composite of Two Dimensional GeSe₂/Nitrogen‐Doped Reduced Graphene Oxide for Enhanced Capacitive Lithium‐Ion Storage

Abstract

A composite of two-dimensional (2D) GeSe 2 nanosheets dispersed on N-doped reduced graphene oxide (GeSe 2 /N-rGO) is fabricated via a simple hydrothermal method combined with post-selenization process. The high electronic conductivity and the substantial void spaces of the wrinkled N-rGO can improve the electrical conductivity of the active material and accommodate the volume evolution of GeSe 2 nanosheets during the (de)lithiation processes, while GeSe 2 nanosheets can reduce ion diffusion length effectively. Meanwhile, the unique layered structure is beneficial to the contact of the active material and electrolyte, and the reversibility of conversion reaction has also been improved. Furthermore, kinetics analysis reveals a pseudocapacitance-dominated Li + -storage mechanism at high rates. In-situ X-ray diffraction analysis discloses that the conversion reaction has played a certain part in Li + -storage. Thus, the GeSe 2 /N-rGO composite delivers excellent rate capability and good long-term stability with a high reversible capacity of 711.0 mA h g À 1 after 2000 cycles at 1 A g À 1 .

Graphite Nanosheets as a Platform for the Nanosize GeSe2 Anode with Improved Electrode Performance

“…This was attributed to the encapsulation effect of the graphite sheets and was consistent with the expected results at the beginning of the experiment. Moreover, the CVs of the samples were in general agreement with the typical GeSe 2 storage Li + reported in the previous period . GeSe 2 played a decisive role in the LIBs charging/discharging process as a conversion-alloyed anode.…”

“…Moreover, the CVs of the samples were in general agreement with the typical GeSe 2 storage Li + reported in the previous period. 25 GeSe 2 played a decisive role in the LIBs charging/discharging process as a conversion-alloyed anode. In this process, GeSe 2 all underwent conversion reactions with Li + first, followed by alloying reactions.…”

Ball-Milling-Assisted Grinding of GeSe2/C Hybrid Anodes for Lithium-Ion Batteries with Enhanced Electrochemical Performance

“…Panels a–c of Figure showed the CV curves of the three samples for the initial 5 cycles at a scan rate of 0.1 mV s –1 between 0.01 and 3.0 V. For comparison, the cycling performance, CV curves, and charge/discharge profiles of carbon pyrolysis from citric acid were also performed, as shown in Figure S2 of the Supporting Information. Among the GeSe 2 , GeSe 2 /C-1, and GeSe 2 /C-2 anodes, the GeSe 2 active materials play a decisive role in the cyclic electrochemical performance, and these anodes will undergo a first conversion and then alloying reaction. − According to the comparative analysis of the three curves, the common denominator was that they can be divided into two groups of redox peaks. The first group of redox peaks located from 3.0 to 0.6 V can be assigned to the multi-step conversion reactions of GeSe 2 to Ge, and the second group of redox peaks located from 0.6 to 0.01 V can be ascribed to Li-ion insertion/extraction into/from Ge crystal lattices, indicating the alloying reaction.…”