Synchrotron X‐ray Spectroscopic Investigations of In‐Situ‐Formed Alloy Anodes for Magnesium Batteries

Abstract

Magnesium batteries present high volumetric energy density and dendrite‐free deposition of Mg, drawing wide attention in energy‐storage devices. However, their further development remains stagnated due to relevant interfacial issues between the Mg anode and the electrolyte and sluggish solid‐state diffusion kinetics of Mg2+ ions. Herein, an in situ conversion chemistry to construct a nanostructured Bi anode from bismuth selenide driven by Li+ is proposed. Through the combination of operando synchrotron X‐ray diffraction, ex situ synchrotron X‐ray absorption spectroscopy, and comprehensive electrochemical tests, it is demonstrated that the nanosize of the in‐situ‐formed Bi crystals contributes to the fast Mg2+ diffusion kinetics and highly efficient Mg–Bi alloingy/de‐alloying. The resultant Bi anodes exhibit superior long‐term cycling stability with over 600 cycles under a high current density of 1.0 A g‐1. This work provides a new approach to construct alloy anode and paves the way for exploring novel electrode materials for magnesium batteries.

Synchrotron Radiation Spectroscopic Studies of Mg2+ Storage Mechanisms in High‐Performance Rechargeable Magnesium Batteries with Co‐Doped FeS2 Cathodes

“…However, insufficient researches have been devoted to their study and to date they tend to demonstrate unsatisfactory electrochemical performance. [ 24 ]…”

“…However, insufficient researches have been devoted to their study and to date they tend to demonstrate unsatisfactory electrochemical performance. [24] The type II metal sulfides have been widely studied. When CuS cathodes with different modified morphologies are used for RMBs, [25] they show a maximum capacity of 477 mAh g -1 at 0.05 A g -1 though cycling life is only 60 cycles.…”

Phase Separation Induced Binary Core–Shell Alloy Nanoparticles Embedded in Carbon Sheets for Magnesium Storage

“…In recent years, a small number of alloy-type anode materials with a special nanostructure such as nanotube, 24 nanocrystal, 25 and mesoporous nanosheet 23 have been proved to have improved electrochemical performance brought about by the nanostructural advantages. 36 Nanosized materials can reduce absolute volume expansion while reducing the diffusion distance of Mg 2+ and improving diffusion kinetics. Furthermore, low-dimensional structural materials such as tubes and sheets can further shorten the Mg 2+ transmission path and accelerate the diffusion kinetics.…”

“…The nanostructure design and morphology engineering surrounding the alloy-type anode material of MIBs should follow the following guidelines: (i) improve the overall structural stability of the material to buffer the volume change during charging and discharging; (ii) increase the low diffusion kinetics of Mg 2+ originating from the high diffusion barrier of Mg 2+ . In recent years, a small number of alloy-type anode materials with a special nanostructure such as nanotube, nanocrystal, and mesoporous nanosheet have been proved to have improved electrochemical performance brought about by the nanostructural advantages . Nanosized materials can reduce absolute volume expansion while reducing the diffusion distance of Mg 2+ and improving diffusion kinetics.…”

Initiating Jahn–Teller Effect in Vanadium Diselenide for High Performance Magnesium‐Based Batteries Operated at −40 °C

“…The calculated diffusion coefficient at RT is 1.67 × 10 −9 cm 2 s −1 which is ≈two orders of magnitude greater than reported. [38][39][40][41] At a low temperature of −20 °C (Figure 5e), 1T-VSe 2 continues to exhibit a high diffusion coefficient of 1.7 × 10 −10 cm 2 s −1 . The fast ion diffusion kinetics and high electronic conductivity of 1T-VSe 2 are directly associated with the J-T effect because of the change in electronic states and local atomic structures to give the excellent low-temp performance of the battery.…”