In‐Depth Mechanism Understanding for Potassium‐Ion Batteries by Electroanalytical Methods and Advanced In Situ Characterization Techniques

Abstract

Figure 2. a) In situ EIS Nyquist plots of FeTe 2 -C. b) In situ EIS graph (R tot vs potential). c) Variation in K + diffusion coefficient of FeTe 2 -C. Reproduced with permission. [48] Copyright 2020, Wiley-VCH. d) Nyquist plots in KFSI. e) DRT analysis of the EIS results in KFSI. Reproduced with permission. [51]

Unique Spindle‐Like Bismuth‐Based Composite toward Ultrafast Potassium Storage

“…where descriptions of these parameters are provided in Figure S20, Supporting Information. [32] As illustrated in Figure 5h, the obtained nice D K + of SPB@NC ranges from 10 −12 to 10 −10 cm 2 s −1 , which is in great accordance with the EIS results and certifies the conducive influence exerting in potassium storage. It is worth mentioning that the D K + during charging process is slight higher than that of discharging process, which may be ascribed to the smoother channels and favorable structure stability performed after depotassiation.…”

Confine, Defect, and Interface Manipulation of Fe3Se4/3D Graphene Targeting Fast and Stable Potassium‐Ion Storage

“…To provide insight into the electrochemical reaction mechanism of DP-Fe 3 Se 4 /3DG, the in situ and ex situ XRD characterizations were performed at different discharge and charge states. [46] As the discharge process proceeds, the Fe 3 Se 4 shows the characteristic peak intensity diminishing and a certain discharge capacity in voltage interval of the initial value to 0.8 V (Figure 5a,b). This indicates that K-ions are inserted into Fe 3 Se 4 crystal structure at this stage and the cell structure of Fe 3 Se 4 allows the K-ion storage in the unfilled octahedral and tetrahedral voids.…”

Fast and Long‐Lasting Potassium‐Ion Storage Enabled by Rationally Engineering Strain‐Relaxation Bi/Bi2O3 Nanodots Embedded in Carbon Sheets

“…High performance electrochemical energy storage devices are essential for the application of storing intermittent, seasonable, and random renewable energy in contemporary society, such as solar and wind energy. [1] The advancement of resourceabundant and cost-effective potassium ion batteries (PIBs) provides a promising guarantee for large-scale energy storage which has been appealed in the post-lithium battery era. [2,3] Nevertheless, the large ion radius of K + remains challenging to the development of PIBs, and thereby massive volume changes and sluggish potassiation kinetics of electrode materials are induced during cycling, resulting in low capacity, poor rate capability, and rapid capacity decay.…”