Pulverization‐Tolerant CuSe Nanoflakes with High (110) Planar Orientation for High‐Performance Magnesium Storage

Abstract

Copper chalcogenides are of great interest as conversion-type cathode materials due to their large specific capacity for rechargeable magnesium batteries, yet are subjected to severe capacity fading brought about by structure collapse in repetitive charge-discharge cycling. Herein, single-crystalline and (110) preferentially oriented CuSe nanoflakes are designed via a temperaturecontrolled crystal growth route under microwave irradiation. The as-prepared CuSe nanoflake cathode materials can present high reversible capacity (204 mAh g −1 at 200 mA g −1 current density), outstanding rate capability, and remarkable long-term cycling stability (≈0.095% capacity decay per cycle at 1 A g −1 within 700 cycles). The multistep reversible conversion mechanism of the CuSe nanoflake cathode materials is evidenced by ex situ X-ray photoelectron spectroscopy and X-ray diffraction. Structure evolution investigation suggests that the single-crystalline CuSe nanoflakes can exhibit relatively durable structural stability. The desirable cycling stability can be ascribed to the excellent pulverization-tolerance of the CuSe nanoflake cathode materials endowed by the multistep reversible conversion mechanism and the single-crystalline feature. Furthermore, the preferentially-oriented (110) active plane is favorable for electrochemical reactions to ensure high specific capacity. This work can afford a crystal engineering strategy to fabricate high-performance conversion-type electrode materials for rechargeable magnesium batteries.

A facile synthesis of CuSe nanosheets for high-performance sodium-ion hybrid capacitors

“…The distinct strong peak at about 257 cm À1 is attributed to the stretching vibration of the Se-Se bond (Se 2 unit) in the hexagonal CuSe, which agrees with the previous report. 27 As shown in the FTIR spectra, broadband was observed at 608 cm À1 , which is attributed to the bending vibration of Cu-Se (Fig. S4 †).…”

“…These evident and sharp diffraction lines at 26.4°, 28.1°, 31.0°, 41.6°, 45.3°, 46.0°, 49.9°, 53.9°, 54.8°, 56.5°, 70.3° and 74.3° could be well fitted with the (101), (102), (006), (106), (107), (110), (108), (201), (202), (116), (208) and (212) planes of the standard PDF card, respectively, and no signal of other components is detected, indicating that the hydrothermally synthesized CuSe has high crystallinity degree and purity. 27 Besides, the Raman spectrum of the CuSe sample is shown in Fig. 2b .…”

“…102), ( 006), ( 106), (107), ( 110), ( 108), ( 201), ( 202), ( 116), ( 208) and (212) planes of the standard PDF card, respectively, and no signal of other components is detected, indicating that the hydrothermally synthesized CuSe has high crystallinity degree and purity. 27 Besides, the Raman spectrum of the CuSe sample is shown in Fig. 2b.…”

Size‐Controllable Nickel Sulfide Nanoparticles Embedded in Carbon Nanofibers as High‐Rate Conversion Cathodes for Hybrid Mg‐Based Battery

“…Theoretically, the voltammetric response of a cathode material can be evaluated as following formulas: where the measured current ( i ) and the scan rate ( v ) obey a power law relationship, and a and b are adjustable parameters. [ 25 , 26 ] The peak current i varies as v 1/2 or v (that is, b = 0.5 or 1), elucidating that the electrochemical system predominates the diffusion process or capacitive‐controlled process, respectively. For one pair of cathodic and anodic response in Figure S9a , Supporting Information, the relationship between log( i ) and log( v ) is presented in Figure S9b , Supporting Information.…”

Revealing the Reaction and Fading Mechanism of FeSe2 Cathodes for Rechargeable Magnesium Batteries

“…[8] Compared with oxides and sulfides, selenides are more advantageous selections as the bigger Se 2À anion (soft base) exhibits a weaker interaction with Mg 2 + cation (hard acid). [9,10] Till now, many types of selenides, either intercalation or conversion, have been reported, such like Cu 2 Se, [11] Cu 2-x Se, [12][13] CuSe, [14][15][16] CoSe 2 , [17] Ni 0.85 Se, [18] Ag 2 Se, [19] VSe 2 [20] and WSe 2 . [21] Generally, these reported selenides show relatively better performance than oxides and sulfides.…”