An Innovative Freeze‐Dried Reduced Graphene Oxide Supported SnS₂ Cathode Active Material for Aluminum‐Ion Batteries

Abstract

Rechargeable aluminum-ion batteries (AIBs) are attractive new generation energy storage devices due to its low cost, high specific capacity, and good safety. However, the lack of suitable electrode materials with high capacity and enhanced rate performance makes it difficult for real applications. Herein, the preparation of 3D reduced graphene oxide-supported SnS nanosheets hybrid is reported as a new type of cathode material for AIBs. The resultant material demonstrates one of the highest capacities of 392 mAh g at 100 mA g and good cycling stability. It is revealed that the layered SnS nanosheets anchored on 3D reduced graphene oxide network endows the composite not only high electronic conductivity but also fast kinetic diffusion pathway. As a result, the hybrid material exhibits high rate performance (112 mAh g at 1000 mA g ). The detailed characterization also verifies the intercalation and deintercalation of relatively large chloroaluminate anions into the layered SnS during the charge-discharge process, which is important for better understanding of the electrochemical process of AIBs.

Self‐Supported Tin Sulfide Porous Films for Flexible Aluminum‐Ion Batteries

“…This result indicates that the aluminum compounds insert into the layered SnS materials, corresponding to higher aluminum concentration after discharging in Figure S5 (Supporting Information). [20,24] An unknown peak around 161.5 eV was found after charging, which is similar to the result using SnS 2 as the active material in AIBs. This variation of binding energy is assigned to the decomposition of aluminum compounds after charging.…”

“…[23] After discharging, the spectra of Sn shifted to low binding energy and more molar ratio of metallic Sn can be observed in the electrode. [20] Similarly, after charging, the spectra of sulfur recovered to the pristine state with a higher binding energy increasing, revealing that a reversible reaction increases the valence state of sulfur. However, after charging, the major peaks shifted to higher binding energy (487.2 and 495.7 eV), demonstrating the increase of the oxidation state of Sn.…”

“…However, after charging, the major peaks shifted to higher binding energy (487.2 and 495.7 eV), demonstrating the increase of the oxidation state of Sn. [20] Further characterization is required to understand this new peak in the future. On the other side, the XPS spectra of sulfur present a similar shift in the pristine, discharged, and charged states.…”

“…After discharging, the 2p spectra of sulfur shifted toward lower binding energy by 0.4 eV, reflecting the decrease of the valence state of sulfur. Based on the above discussion, the proposed electrochemical process during charging/discharging processes can be proposed as follows: [20] In the charging process ( ) It is clearly observed that a small satellite peak of S 6+ located around 168 eV after charging and discharging, owing to the oxidation of S 2− during the reaction.…”

Insertion of Mono- vs. Bi- vs. Trivalent Atoms in Prospective Active Electrode Materials for Electrochemical Batteries: An ab Initio Perspective

“…The available experimental voltage for the full lithiation of VO 2 to LiVO 2 (~2.0 V [124]) was reasonably well matched by our computational model. The predicted convex hulls and voltage-composition curves for Mg and Al insertions (Figure 11) demonstrate that positive voltages can be maintained up to the concentrations of MgVO 2 and Al 0.5 VO 2 (beyond the expected Mg 0.5 VO 2 and Al 0.33 VO 2 , respectively, based on vanadium redox), resulting in specific capacities among the highest for existing Mg [144][145][146] and Al [126,147,148] one-electron vanadium reduction chemistry. This was confirmed in [34], where we explored effects of Li, Mg and Al concentration on insertion energetics in VO2(R).…”