Two‐Dimensional NiO@C‐N Nanosheets Composite as a Superior Low‐Temperature Anode Material for Advanced Lithium‐/Sodium‐Ion Batteries

Most of the anodes used in lithium‐/sodium‐ion batteries (LIBs/SIBs) have poor low‐temperature (LT) performances, which severely limit their applications under LT environment. Herein, two‐dimensional nickel oxide nanosheet encapsulated in N‐doped carbon coated layer (abbreviated as NiO@C−N NSs) is successfully prepared and investigated for the first time as a LT anode for LIBs/SIBs. As a result, the prepared NiO@C−N NSs electrode delivers a high room temperature (RT) Li‐storage capacity (1036 mA h g −1 at 0.05 A g −1 ) and excellent LT Li‐storage performance (428 mA h g −1 at 0.05 A g −1 at −40 °C). Furthermore, the prepared NiO@C−N NSs also exhibits a superior RT Na‐storage capacity of 529 mA h g −1 at 0.05 A g −1 and superior LT Na‐storage performance. Through electrochemical impedance spectroscopy analysis, we find that the LT Li‐/Na‐storage performances of NiO@C−N NSs electrodes are mainly dominated by the R SEI of SEI membrane formation at the electrode/electrolyte interface. Moreover, the LT Li‐/Na‐storage properties of NiO@C−N NSs can be effectively improved by using commercial LT electrolyte with low viscosity and low melting point.