Sulfur-doped porous carbon as high-capacity anodes for lithium and sodium ions batteries

Sucrose–Thiourea-Derived Nitrogen and Sulfur Co-doped Hierarchically Porous Carbon Nanosheets as a High-Performance Negative Electrode for Sodium-Ion Batteries

“…30 Subsequently, during the positive voltage sweep, small peaks emerged at 1.6 and 2.2 V (Figure 6b) as a result of the transformation of Na x S into the polysulfides. 39,40 The peak intensity gradually decreases, and cycling reversibility is found to be improved, which indicates the stable SEI layer formation, which could be understood in the successive cycles. However, during reduction, a small shoulder peak emerged at ∼0.7 V, owing to the probable insertion of sodium ions into the host.…”

“…In the initial cathodic voltage sweep, the reduction peak noticed between 0.3 and 1.6 V is due to solid–electrolyte interphase (SEI) formation caused by the electrolyte decomposition and irreversible reaction of Na + with functional groups . Subsequently, during the positive voltage sweep, small peaks emerged at 1.6 and 2.2 V (Figure b) as a result of the transformation of Na x S into the polysulfides. , The peak intensity gradually decreases, and cycling reversibility is found to be improved, which indicates the stable SEI layer formation, which could be understood in the successive cycles. However, during reduction, a small shoulder peak emerged at ∼0.7 V, owing to the probable insertion of sodium ions into the host.…”

“…Similarly, the N 1s spectrum (Figure d) split into three peaks, attributed to highly active graphitic nitrogen (∼401.1 eV), pyrrolic nitrogen (∼400.6 eV), and pyridinic nitrogen (∼397.8 eV) . Additionally, the S 2p spectrum (Figure e) exhibits three peaks assigned to S 2p 3/2 (163.5 eV) and S 2p 1/2 (164.6 eV) of the −C–S–C– covalent bond and the peak observed at 168.2 eV ascribed to sulfoxide groups (C–SO x –C). ,, In addition, atomic weight percentages of STU are tabulated in Table . These observations confirm the existence of nitrogen and sulfur on the surface of STU.…”

“…15 Additionally, the S 2p spectrum (Figure 2e) exhibits three peaks assigned to S 2p 3/2 (163.5 eV) and S 2p 1/2 (164.6 eV) of the −C−S−C− covalent bond and the peak observed at 168.2 eV ascribed to sulfoxide groups (C−SO x −C). 15,39,40 In addition, atomic weight percentages of STU are tabulated in Table 1. These observations confirm the existence of nitrogen and sulfur on the surface of STU.…”

Structural Engineering in Graphite‐Based Metal‐Ion Batteries

“…The interlayer-insertion storage mechanism is quite preferred in comparison with the pore-filling storage mechanism which occurs only at low potentials and the conversion storage mechanism which usually render big volume expansion during charging/discharging process. [12] Besides, owning to the advantages of abundant resources, low voltage platform, high conductivity and ecofriendliness, graphite is undoubtedly the most promising electrode material for EES. [13] However, the interlayer distance of graphite is small, which directly impedes some lager ions such as Na + and K + from inserting into the interlayer space, leading…”