Tellurium: A High-Performance Cathode for Magnesium Ion Batteries Based on a Conversion Mechanism

Abstract

Magnesium ion batteries (MIBs), due to the low redox potential of Mg, high theoretical capacity, dendrite-free magnesiation, and safe nature, have been recognized as a post-lithium energy storage system. However, an ongoing challenge, sluggish Mg2+ kinetics in the small number of available cathode materials of MIBs, restricts its further development. The existing cathodes mostly deliver unsatisfactory capacity with poor cycling life based on the traditional ion-intercalation mechanism. Herein, we fabricated a conversion-type Mg∥Te battery based on a reversible two-step conversion reaction (Te to MgTe2 to MgTe). High discharge capacities (387 mAh g–1) and rate capability (165 mAh g–1 at 5 A g–1) can be achieved. The diffusivity of Mg2+ can reach 3.54 × 10–8 cm2 s–1, enabled by the high electrical conductivity of Te and increased surface conversion sites. Subsequently, ab initio molecular dynamics simulation was also carried out to further confirm the conversion mechanism and fast Mg2+ transportation kinetics.

Implanting CuS Quantum Dots into Carbon Nanorods for Efficient Magnesium‐Ion Batteries

“…[ 41 ] As depicted in Figure 4d, the b values are 0.73, 0.83, and 0.87 at peaks 1, 2, and 3, respectively, indicating that the electrochemical reactions are dominated by mixed processes. The capacitive controlled contribution can be further expressed by the following equation: [ 42 ] $$\[ \begin{array}{*{20}{c}}{i({\rm{V}}) = {k_1}v + {k_2}{v^{1/2}}}\end{array} \]$$where k 1 and k 2 are constant parameters. In Figure 4e,f, the redox capacitance contribution increases from 50.5% to 90.4% as the scan rate elevates from 0.1 to 1.0 mV s −1 .…”

“…[41] As depicted in Figure 4d, the b values are 0.73, 0.83, and 0.87 at peaks 1, 2, and 3, respectively, indicating that the electrochemical reactions are dominated by mixed processes. The capacitive controlled contribution can be further expressed by the following equation: [42] (V) 1…”

Energy Storage Mechanism of C12-3-3 with High-Capacity and High-Rate Performance for Li/Mg Batteries

“…3−5 In the previous reports, the stateof-the-art anode materials for Mg batteries focus on Mg metal, Mg alloys, intercalation-type anodes, and so on. 6,7 Nevertheless, the passivation film, corrosion, and fewer Mg-dendrites on the Mg surface in most electrolytes hamper the practical development of MIBs. 8,9 Further, intermetallic anodes are notoriously resulting from their volumetric expansion.…”

“…One of the strategies is to develop novel metal batteries. Very recently, Mg-ion batteries (MIBs) have received tremendous attention because of prominent volumetric capacity, high safety performance, and abundant resources of Mg anodes. − In the previous reports, the state-of-the-art anode materials for Mg batteries focus on Mg metal, Mg alloys, intercalation-type anodes, and so on. , Nevertheless, the passivation film, corrosion, and fewer Mg-dendrites on the Mg surface in most electrolytes hamper the practical development of MIBs. , Further, intermetallic anodes are notoriously resulting from their volumetric expansion . Additionally, the traditional intercalation-type materials, such as graphene, are not suitable for anode materials for MIBs without the property of Mg-affinity.…”

De-Ammonium Ba0.18V2O4.95/NH4V4O10 Film Electrodes as High-Performance Cathode Materials for Magnesium-Ion Batteries

“…In particular, the development of suitable cathode materials for MIBs remains challenging. This is due to the inevitable strong electrostatic interaction between Mg 2+ and the cathode material (high charge/radius ratio) that hinders this process, resulting in a slow solid-state diffusion of multivalent ions. − Therefore, the cathode materials must provide reasonable rate performance and fast ion diffusion channels to take full advantage of the theoretically higher capacity due to the divalent nature of Mg. , Several advances have been made in cathodes capable of reversibly inserting Mg 2+ into MIBs such as CuHCF, Cu 2‑x Se, VS 4 , V 2 O 5 , WO 3 , h -MoO 3 , FePO 4 , Mg 2 MnO 4 , etc. However, these materials do not provide desirable electrochemical performance.…”