Balanced Crystallinity and Nanostructure for SnS₂ Nanosheets through Optimized Calcination Temperature toward Enhanced Pseudocapacitive Na⁺ Storage

Abstract

Sodium ion batteries (SIBs) are expected to take the place of lithium ion batteries (LIBs) as next-generation electrochemical energy storage devices due to the cost advantages they offer. However, due to the larger ion radius, the reaction kinetics of Na+ in anode materials is sluggish. SnS2 is an attractive anode material for SIBs due to its large interlayer spacing and alloying reactions with high capacity. Calcination is usually employed to improve the crystallinity of SnS2, which could affect the Na+ reaction kinetics, especially the pseudo­capacitive storage. However, excessively high temperature could damage the well-designed nanostructure of SnS2. In this work, we uniformly grow SnS2 nanosheets on a Zn-, N-, and S-doped carbon skeleton (SnS2@​ZnNS). To explore the optimal calcination temperature, SnS2@​ZnNS is calcined at three typical temperatures (300, 350, and 400 °C), and the electrochemical performance and Na+ storage kinetics are investigated specifically. The results show that the sample calcined at 350 °C exhibited the best rate capacity and cycle performance, and the reaction kinetics analysis shows that the same sample exhibited a stronger pseudo­capacitive response than the other two samples. This improved Na+ storage capability can be attributed to the enhanced crystallinity and the intact nanostructure.

Facile Construction of Nano-Dimensional Bi Encapsulated in N-Doped Porous Carbon Frameworks for High-Performance Sodium-Ion Hybrid Capacitors

“…The Na + diffusion coefficient can be calculated from the Fick's second law by using eq S1. 49,50 gradually decrease during the alloying and dealloying reactions. 40,51 The Bi@NPC-850-U electrode owns the highest Na + diffusion coefficient in four anodes, indicating the fastest reaction kinetics, thus exhibiting outstanding electrochemical performance especially at a high current rate.…”

“…The corresponding curves were obtained in the third cycle at a current pulse of 0.1 A g –1 for 10 min with a rest for 30 min to reach a quasi-equilibrium potential (Figure a). The Na + diffusion coefficient can be calculated from the Fick’s second law by using eq S1. , Figure b,c shows the changing processes of the Na + diffusion coefficient during the discharging and charging processes, respectively. The calculated values of D Na+ range from 10 –12 to 10 –9.5 cm 2 s –1 and present the similar changing trend, that is the D Na+ values gradually decrease during the alloying and dealloying reactions. , The Bi@NPC-850-U electrode owns the highest Na + diffusion coefficient in four anodes, indicating the fastest reaction kinetics, thus exhibiting outstanding electrochemical performance especially at a high current rate.…”

Low-Dimensional and High-Crystallinity Carbonyl Cathodes Prepared by Physical Vapor Deposition for Green Aluminum Organic Batteries

“…In fact, the stronger the diffraction peaks for each crystal plane, the more uniform the orientation of the grains. 37 We calculated the relative crystallinity of PTCDA, PTCDA(Ss), and PTCDA(G) three samples, as shown in Figure 2. The calculated results of the relative crystallinity of the three samples (PTCDA, PTCDA-(Ss), and PTCDA(G)) were 0.86, 0.92, and 0.91, respectively.…”

Polycrystalline Fe- and Sn-based sulfides for high-capacity sodium-ion battery anodes

“…Unfortunately, SnS 2 -based anodes still suffer from several drawbacks that hinder their applications, including poor conductivity, rapid capacity decay, and low material utilization rate. 6,7 The introduction of highly electrically conductive phases and the creation of lattice boundary/interfaces to accelerate the Na + /e À diffusion have proven to be effective ways to address these problems. 8,9 In SnS 2 , Sn displays its highest valence state and S its lowest-and crystal boundary/interfaces may be formed here by redox reactions, with transition metals serving as suitable reductants.…”

“…Unfortunately, SnS 2 -based anodes still suffer from several drawbacks that hinder their applications, including poor conductivity, rapid capacity decay, and low material utilization rate. 6,7…”