Sodium/Potassium‐Ion Batteries: Boosting the Rate Capability and Cycle Life by Combining Morphology, Defect and Structure Engineering

Abstract

Carbon‐based materials have been considered as the most promising anode materials for both sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs), owing to their good chemical stability, high electrical conductivity, and environmental benignity. However, due to the large sizes of sodium and potassium ions, it is a great challenge to realize a carbon anode with high reversible capacity, long cycle life, and high rate capability. Herein, by rational design, N‐doped 3D mesoporous carbon nanosheets (N‐CNS) are successfully synthesized, which can realize unprecedented electrochemical performance for both SIBs and PIBs. The N‐CNS possess an ultrathin nanosheet structure with hierarchical pores, ultrahigh level of pyridinic N/pyrrolic N, and an expanded interlayer distance. The beneficial features that can enhance the Na‐/K‐ion intercalation/deintercalation kinetic process, shorten the diffusion length for both ions and electrons, and accommodate the volume change are demonstrated. Hence, the N‐CNS‐based electrode delivers a high capacity of 239 mAh g−1 at 5 A g−1 after 10 000 cycles for SIBs and 321 mAh g−1 at 5 A g−1 after 5000 cycles for PIBs. First‐principles calculation shows that the ultrahigh doping level of pyridinic N/pyrrolic N contributes to the enhanced sodium and potassium storage performance by modulating the charge density distribution on the carbon surface.

Energetic Metal–Organic Frameworks Derived Highly Nitrogen‐Doped Porous Carbon for Superior Potassium Storage

“…This can be understood as the broadening of interlayer after potassium insertion at a low current density. [36] Furthermore, the pyrrolic and pyridinic N-induced defects are active sites for adsorbing potassium ions. With the adsorption of potassium ions at the active sites, the defects decrease, leading to the decrease of I D /I G value.…”

“…[26][27][28][29][30][31][32][33][34] As demonstrated by calculation and experimental study, the pyrrolic N and pyridinic N were suggested to be effective in enhancing the reversible capacity of the electrode. [18,[35][36][37][38] However, developing N-doped carbon materials with high concentration of easily accessible active N species (pyrrolic and pyridinic N) for enhanced PIBs performance still remains challenging.…”

Structural Engineering of SnS2Encapsulated in Carbon Nanoboxes for High‐Performance Sodium/Potassium‐Ion Batteries Anodes

“…As is shown, the spectrum of N 1s is deconvoluted into three peaks at ≈400.1 eV (N-5, Pyrrolic-N), ≈398.3 eV (N-6, Pyrindinic-6), and ≈401.5 eV (N-Q, Graphitic-N), respectively. [51][52][53] In S 2p spectrum, three deconvoluted peaks located at 161.5, 163.1, and 164.5 eV, corresponding to S 2p 3/2 , S 2p 1/2 , and C-S bonds, respectively. [54,55] This is positive because strong coupling effect will occur at the heterointerface due to the heteroatoms doping induced electron cloud bias, thereby effectively accelerating the electron transport and offering more active sites for Na + /K + storage.…”

A Nanocomposite of Si@C Nanosphere and Hollow Porous Co9S8/C Polyhedron as High‐Performance Anode for Lithium‐Ion Battery

“…are consisted of a semicircle at the high-to medium-frequency region and an inclined straight line at the low-frequency region. According to previous literature, the semicircle belongs to the resistance of SEI film (R SEI ) and the charge-transfer resistance (R ct ), [43,44,45] and the straight line can be assigned to the lithium ion diffusion in electrodes, known as the Warburg impedance (Z w ). [46,47,48] As shown in Figure 6a, in comparison to Si@C anodes, the Si@CÀ Co 9 S 8 /C anodes show the relative lower R ct , suggesting high electrical conductivity of the Si@CÀ Co 9 S 8 /C anodes.…”