Tailoring Rod‐Like FeSe₂ Coated with Nitrogen‐Doped Carbon for High‐Performance Sodium Storage

Abstract

Designing potential anodes for sodium-ion battery with both remarkable durability and high-rate capability has captured enormous attention so far. The engineering of size and morphology is deemed as an effective manner to boost the electrochemical properties. Owing to the anisotropic self-assembly of iron selenide, rod-like FeSe 2 coates with nitrogen-doped carbon is prepared through the thermal reaction of Prussian blue with selenium. Notably, the cyano groups are effectively transformed into N-doped carbon with FeNC bonds, which uniformly coats FeSe 2 , prompting Na + transportations. Interestingly, the particle size is tailored by heating rates, along with increased carbon content, leading to broadened energy levels for redox reaction. Bestowed by these advantages, the FeSe 2 /N-C as Na-storage anode delivers impressive electrochemical properties. Even at a rather high rate of 10.0 A g −1 , a considerable capacity of 308 mAh g −1 is yielded over 10 000 loops. Supported by the detailed analysis of kinetic features, reduced size of particles could bring about the enhanced contributions of pseudocapacitive and quickening rate of ions transferring. The phase evolutions are further investigated by in situ EIS and ex-situ technologies. The work is expected to provide a new strategy to prepare metal-selenide with controllable size and induce the faster kinetic of high-rate materials.

Synthesis Process of CoSeO3 Microspheres for Unordinary Li‐ion Storage Performances and Mechanism of Their Conversion Reaction with Li ions

“…In the first discharge process, the R tot value was maintained until −1.28 V, after which it increased rapidly. This increase in R tot was attributed to structural stress induced by reduction of the CoSeO 3 phase and volume expansion, which was in agreement with the reduction peaks in the CV curve of the first discharge process shown in Figure a . In addition, the formation of the SEI layer, which was thick and possessed resistive characteristics, contributed to the increase in the R tot value .…”

Nature of FeSe2/N‐C Anode for High Performance Potassium Ion Hybrid Capacitor

“…The state of the valence and chemical bonds of the elements in FeSe 2 /N-C is further analyzed by XPS. [48,49] The C peak (Figure 1f) is separated into two peaks at 284.5 and 285.7 eV, corresponding to CC and CN. The high resolution of Fe 2p spectrum ( Figure S8, Supporting Information)shows two major peaks at 706 and 720 eV, assigned to Fe 2p3/2 and Fe 2p1/2.…”

Accurate Control Multiple Active Sites of Carbonaceous Anode for High Performance Sodium Storage: Insights into Capacitive Contribution Mechanism

“…During the sodiation process, the charge transfer resistance ( R CT ) is on an upward trend derived from the formation of NaS 2 , accompanying with heteroatomic phase transformation process. Phase transformation behavior would leading to active sites volume expansion, and hence slightly expanding the lattice spacing of carbon layer accompany with the enlargement of resistance . During the desodiation process, the R CT of each voltage points are on opposite trend, which is attributed to lattice contraction.…”

“…Representative lithium ion batteries (LIBs) have captured tremendous attentions; however, the serious contradiction between enormous industrial requirements and exceeding insufficiency of lithium resource has rapidly elevated its price, which further restricts its wide‐scale application . Thus, room‐temperature sodium‐ion batteries (RT‐SIBs) are extensively explored as promising candidates owing to their wide availability and similar electrochemical behavior like rocking‐chair principle of LIBs . Nonetheless, the larger radius of sodium (1.02 Å) compared with lithium (0.76 Å) causing serious volume expansion during the storage/release processes .…”