N‐Doped graphene embellished with Co ₉ S ₈ enable advanced sulfur cathode for high‐performance lithium‐sulfur batteries

Abstract

Summary Lithium‐sulfur batteries have drawn widespread attention as favorable energy storage systems. However, the low conductivity of S gives rise to a poor specific capacity. Moreover, the shuttle effect of soluble lithium polysulfides (LiPS) causes a rapid performance deterioration in Li‐S systems. Herein, Co9S8 implanted on N‐doped graphene (Co9S8‐NG) is proposed to support S in cathodes. The N‐doped graphene substantially enhanced the electronic conductivity of the S‐based cathode. Meanwhile, Co9S8 with a high polarity not only effectively immobilized the LiPS species through chemical binding but also considerably catalyzed the LiPS electrochemical conversion, ultimately suppressing its shuttle effect. As expect, the cathode with the Co9S8‐NG composite demonstrated high specific capacities of 1051.5 and 564.6 mA h g−1 at 0.2 and 2 C, respectively. Moreover, a satisfactory cycling stability was displayed at 1 C for 400 cycles, with an average capacity fading of 0.085% per cycle. Therefore, Co9S8‐NG was exhibited to improve the cathode performance in numerous aspects and can be regarded as a potential host material to improve the overall performance of Li‐S batteries.

Synergistic effect of titanium‐oxide integrated with graphitic nitride hybrid for enhanced electrochemical performance in lithium‐sulfur batteries

“…Additionally, the oxidation reaction peak around 2.50 V can be ascribed to the conversion of insoluble Li 2 S 2 /Li 2 S to soluble polysulfide (Li 2 S n , 4 ≤ n ≤ 8). The shapes of CV curves of the two cells are similar 43 . However, the TOCN can lower the polarization (Δ = 0.46 V) and enhance the electrochemical reaction kinetics 44 .…”

“…The shapes of CV curves of the two cells are similar. 43 However, the TOCN can lower the polarization (Δ = 0.46 V) and enhance the electrochemical reaction kinetics. 44 In Figure 4B, the discharging voltage platforms corresponding to the two kinds of electrodes are consistent with the CV curves.…”

Graphene oxide coated nanosheet‐like γ‐MnS @ KB‐S fabricated by spray drying for high energy density Li‐S batteries

“…As more lithium polysulfides are confined in the cathode area, more end product of the discharging process will be formed and increase the interface contact resistance (R 2 ), which can be reflected in Figure 12C and Figure 12D. As Table 2 shows, when compared to other similar works, 21,22,25,[28][29][30][50][51][52][53][54] our GO@MKB-S composite cathodes reveal relatively good electrochemical performance. GO@MKB-S sample shows superiority in both sulfur loading (5 mg cm −2 ) and cycle retention rate (200 cycles, 78.69%), which is important in the index of Li-S battery.…”

Fabrication of a Sandwich‐like VS4‐Graphene Composite via Self‐assembly for Highly Stable Lithium‐ion Batteries

“…The appearance of the CÀ S bonds indicates a decent level of interaction between VS 4 and graphene. [41] The results in Figure 1(d) show that V2p 3/2 and V2p 1/2 yield two peaks (around 516.5 and 523.8 eV, respectively), implying the presence of V 4 + . [42] Three peaks are also obtained in the S 2p XPS spectrum (Figure 1(e)).…”