An Investigation into the Charge‐Storage Mechanism of MnO@Graphite as Anode for Lithium‐Ion Batteries at Low Temperature

Abstract

Electrochemical features and the charge‐storage mechanism of monodispersed MnO nanoparticles anchored on graphite (MnO@Graphite) for Li‐ion batteries have been investigated at a low‐temperature of −25 °C. MnO@Graphite nanocomposite rendered a remarkable reversible capacity of 456 mA h g−1 after 320 cycles under a current density of 100 mA g−1 at such a low temperature. Remarkable reversible capacity could be ascribed to the integrated structure, emergence of in‐situ formed MnO2 and hybrid pseudocapacitance. Hybrid pseudocapacitive contributions have appeared at low operational temperature, i. e., assembled heterogeneous intercalation pseudocapacitance at low potentials and surface‐controlled pseudocapacitance at high potentials. The results showed that the prepared MnO@Graphite nanocomposite is a promising candidate for Li‐ion batteries operated in harsh environment.

Stable Lithium Storage at Subzero Temperatures for High‐capacity Co3O4@graphene Composite Anodes

“…Figure 7b shows the reversible capacities delivered at different operating temperatures with increasing current rates. At −20 °C, the capacities of the Co 3 O 4 @G electrode were 758.0, 680.8, 593.1, 502.5, 454.6, 362.0, 291.7 and 169.2 mAh g −1 at current densities of 0.05, 0.1, 0.2, 0.4, 0.5, 0.8, 1.0 and 2.0 A g −1 , respectively, much higher than those of previously reported anode materials which also operated at the same subzero temperature [47,49,51–53] . As shown in Figure 7c, the Co 3 O 4 @G anode exhibits superior capacity retention with high current rates at subzero temperatures than the intercalation‐type graphite [53] and, conversion‐type MnO@G and FeS 2 @G anodes ,[49][52] .…”

“…The main reason for the difference in the first discharge curve of Co 3 O 4 and Co 3 O 4 @G based batteries may be caused by the different electron conductivity on the surface and interior of Co 3 O 4 nanoparticles derived from the introduction of graphene. Figure 6b shows that the Co 3 O 4 @G composite can retain superior low temperature capacity retentions compared with the pure Co 3 O 4 and the other reported low temperature anode materials [27,44–51] . The reversible capacity of Co 3 O 4 @G in the first cycle is 920.4 mAh g −1 at an operating temperature of 30 °C with 0.2 A g −1 current density, while the capacity retention ratios at 0, −10, −20 and −30 °C are 86.8%, 79.4%, 64.5% and 58.4%, respectively.…”

Hybrid Charge‐Storage Route to Nb2CTxMXene as Anode for Sodium‐Ion Batteries

“…Such a feature was also observed to occur in MoS 2 , carbon nanofibers and V 2 O 3 . In our previous works, intercalation pseudocapacitance was also detected to emerge in sulfur‐decorated Ti 3 C 2 MXene and assembled heterogeneous MnO@Graphite at low potentials . Therefore, the intercalation pseudocapacitance has emerged in Nb 2 CT x MXene in the low potential region, particularly in desodiation process.…”

Fast Sodium Storage with Ultralong Cycle Life for Nitrogen Doped Hollow Carbon Nanofibers Anode at Elevated Temperature

“…Intuitively, the slightly elevated temperature seems to be beneficial to enhance reaction kinetics of rechargeable batteries, as our previous reports about Li‐ion batteries. [ 11–14 ] However, the attribute of SIBs may be of huge difference due to various cathode/anode/electrolyte/separator and potential different charge storage mechanism. Particularly, for sodium ion half‐cells, the high activity of sodium metal may lead to unexpected side reactions of electrolyte, affecting the electrochemical performance of the battery.…”