Adsorption and migration of alkali metals (Li, Na, and K) on pristine and defective graphene surfaces

Abstract

Identification of defects proved to be beneficial for metal storage and adsorption on graphene, but are detrimental to metal migration, hence affecting the battery performance.

Nickel‐Catalyzed Synthesis of 3D Edge‐Curled Graphene for High‐Performance Lithium‐Ion Batteries

“…This is because during the process of destroying the graphite close‐packed structure, a large number of defects and oxygen‐containing groups are formed on the surface of the graphene, which increases the degree of surface disorder of the 3D ECG. Interestingly, these defects have a significant positive impact on increasing the lithium storage capacity of carbon materials …”

“…The cathodic peak at around 1.4 V might originate from the reaction of Li ions with functional groups on the surfaces of 3D ECG . The cathodic peak (0.5 V) in the 1st cycle and disappeared in the following cycles could be assigned to the decomposition of the electrolyte and formation of solid electrolyte interphase (SEI) film . A pair of redox peaks below 0.2 V corresponds to the insertion and extraction of Li ions in the graphite layer .…”

“…Interestingly, these defects have a significant positive impact on increasing the lithium storage capacity of carbon materials. [35,36] In order to further investigate the pore structure of 3D ECG, the N 2 adsorption and desorption test was carried out, and the results are shown in Figure 4c,d. The N 2 adsorption and desorption isotherms of the 3D ECG (Figure 4c) clearly show a type IV curve with the hysteresis loop at p/p 0 ≈ 0.45-1.0, which indicates the presence of abundant mesopores.…”

“…[39,40] The cathodic peak (0.5 V) in the 1st cycle and disappeared in the following cycles could be assigned to the decomposition of the electrolyte and formation of solid electrolyte interphase (SEI) film. [35] A pair of redox peaks below 0.2 V corresponds to the insertion and extraction of Li ions in the graphite layer. [41] From the second cycle onward, it is important to note that the CV curves almost overlapped, suggesting the formation of the stable SEI films and superior reactive reversibility of the 3D ECG.…”

Mechanism of Sodium Storage in Hard Carbon: An X‐Ray Scattering Analysis

“…[11] In addition, previous computational studies have suggested that the edge and defect sites on the carbon surface allow sodium to be adsorbed in the high-potential region. [12][13][14][15][16] The present generally accepted view is that hard carbon involves three types of storage sites: 1) the defects and edges on the graphene, 2) graphene-graphene interlayers, and 3) nanopores. However, the assignment of the aforementioned three storage mechanisms to the charge-discharge voltage profile is still controversial.…”