Conversion Reaction Mechanism for Yolk‐Shell‐Structured Iron Telluride‐C Nanospheres and Exploration of Their Electrochemical Performance as an Anode Material for Potassium‐Ion Batteries

Abstract

materials for SIBs. [10-12] Zhang et al. reported on the Na-ion storage activity of CoTe 2 based on the redox mechanism. [10] They found that CoTe 2 nanocrystals transformed into metallic Co and Na 2 Te during the discharge process and the CoTe 2 phase was reversibly formed during repeated cycles. A composite of CoTe 2 and graphene also exhibited excellent gravimetric and volumetric Na ion storage performance. Sun et al. found that layered NiTe 2 nanoparticles anchored on carbon nanosheets exhibit ultrafast and prolonged Na-ion storage. [11] Cho et al. reported on the reversible Na-ion storage mechanism for FeTe 2 , described by FeTe 2 + 4Na + + 4e-↔ Fe + 2Na 2 Te. [12] Despite this level of research, to the best of our knowledge, there is very little literature on the K-ion storage characteristics of transition metal tellurides. The structural optimization of TMC materials is vital for improving their electrochemical properties. [13-15] Nanostructured composites of TMC and carbonaceous materials have been prevalently studied as efficient anode materials for the storage of alkali ions. TMC nanomaterials with highly conductive carbon shell housings may exhibit improved structural stability as well as increased long-term cycling performance and electrical conductivity, leading to a high rate performance. [16,17] Thus, a yolk-shell structure with a TMC@void@C configuration may be considered a highly efficient nanostructure for alkali-ion storage. However, research on nanostructured transition metal telluride materials for energy storage is lacking owing to their restricted synthesis procedure. This study explores a unique-structured nanocomposite of iron telluride (FeTe 2) and carbon as a novel anode material for K-ion storage. Hollow carbon nanospheres housing iron telluride nanocrystals (FeTe 2-C) provided a sufficient amount of space to accommodate the substantial volume change in the nanocrystals during the alloying and de-alloying reactions. The pulverization of the nanocrystals during the cycles was restricted within solid hollow carbon nanospheres and there was no loss of iron telluride nanocrystals from the electrode during the cycles. As such, the essential properties of iron Various metal chalcogenide materials have been investigated as novel candidate anode materials for K-ion batteries (KIBs). This pioneering study explores the electrochemical reaction between K-ions and iron telluride. A detailed analysis is performed using in situ and ex situ methods, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and cyclic voltammetry (CV), following the initial discharging and charging processes. The reversible reaction mechanism, from the second cycle of the reaction of FeTe 2 with K-ions, is 2Fe + K 5 Te 3 + K 2 Te ↔ 2FeTe 1.1 + 1.8Te + 7K + + 7e-. Hollow carbon nanospheres housing iron telluride nanocrystals (FeTe 2-C) are synthesized via facile infiltration and a one-step tellurization process to compensate for the substantial volume change of n...

Rational Design of Yolk–Shell ZnCoSe@N‐Doped Dual Carbon Architectures as Long‐Life and High‐Rate Anodes for Half/Full Na‐Ion Batteries

“…In principle, the value of b = 0.5 stands for a typical diffusion‐controlled behavior, whereas a value of b = 1 implies a surface‐induced capacitive process. [ 49 ] In Figure 6b, the b values of five peaks are 0.95, 0.82, 0.96, 0.98, and 0.81, respectively, telling us that the whole redox kinetics of ZnCoSe@NDC electrode are mainly controlled by the surface capacitance‐dominated behavior. Moreover, the ratio of capacitive contributions can be quantified comply with the formulas below [ 50 ] …”

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

“…While for the conversion electrodes, Kang and colleagues synthesized yolk‐shell FeTe 2 ‐C anode and subjected to in situ EIS to explore the conversion reaction mechanism for the electrode. [ 48 ] They suggested that the total resistance ( R tot ) of FeTe 2 ‐C consist of the interface resistance ( R suf ) and the charge transfer resistance ( R ct ). But it was difficult to distinguish resistance components.…”

“…c) Variation in K + diffusion coefficient of FeTe 2 -C. Reproduced with permission. [48] Copyright 2020, Wiley-VCH. d) Nyquist plots in KFSI.…”

Carbon‐based anode materials for potassium‐ion batteries: From material, mechanism to performance

“…Intercalation‐conversion materials mainly consist of transition metal compounds, which mainly include oxides, 104‐106 sulfates, 107‐109 selenides, 110,111 and tellurides 112,113 with the reaction of M a X b + (b.n)K ↔ K bn M a X b ↔ a M + b K n X for PIBs. M denotes the transition metal like Fe, Co, Ni, Mo, Re, and so on, X denotes the anion (O, S, Se, Te, etc .…”