Enhanced Potassium-Ion Storage of the 3D Carbon Superstructure by Manipulating the Nitrogen-Doped Species and Morphology

Abstract

Potassium-ion batteries (PIBs) are attractive for grid-scale energy storage due to the abundant potassium resource and high energy density. The key to achieving high-performance and large-scale energy storage technology lies in seeking eco-efficient synthetic processes to the design of suitable anode materials. Herein, a spherical sponge-like carbon superstructure (NCS) assembled by 2D nanosheets is rationally and efficiently designed for K+ storage. The optimized NCS electrode exhibits an outstanding rate capability, high reversible specific capacity (250 mAh g−1 at 200 mA g−1 after 300 cycles), and promising cycling performance (205 mAh g−1 at 1000 mA g−1 after 2000 cycles). The superior performance can be attributed to the unique robust spherical structure and 3D electrical transfer network together with nitrogen-rich nanosheets. Moreover, the regulation of the nitrogen doping types and morphology of NCS-5 is also discussed in detail based on the experiments results and density functional theory calculations. This strategy for manipulating the structure and properties of 3D materials is expected to meet the grand challenges for advanced carbon materials as high-performance PIB anodes in practical applications.

A review of hard carbon anode: Rational design and advanced characterization in potassium ion batteries

“…The optimized procedure led to progressively exposing the N‐rich active facets (Figure 6H). 71 After optimization, the obtained N‐rich carbon delivered high reversible specific capacity of 250 mAh g −1 at 200 mA g −1 after 300 cycles and excellent rate capability. To deeply understand the relationship between the N‐species contents and molecular structure, the formation energies of three N‐doped structures were calculated by DFT computation.…”

“…(H) Schematic illustration of the hierarchical structure evolution of spherical sponge‐like carbon. Reproduced with permission from Reference 71. Copyright 2021, Springer…”

Oxygen-Containing Functional Groups Regulating the Carbon/Electrolyte Interfacial Properties Toward Enhanced K+ Storage

“…However, since K + has a larger ionic radius, 1.38 vs 0.76 Å (Li + ), the development of K-based host materials with large interlayer distance is needed. Enormous investigations have been dedicated to, for example, carbonaceous materials because they are cheap, electrically conductive and highly controllable in terms of structure/ composition [1,2]. Early in 2015, highly reversible K + de-/ intercalation in graphite was reported [3][4][5].…”

Eliminating Stubborn Insulated Deposition by Coordination Effect to Boost Zn Electrode Reversibility in Aqueous Electrolyte

“…The huge advantages in energy density, cycle stability, and output voltage make lithium-ion batteries (LIBs) available and popular ( Clément et al, 2020 ; Liu et al, 2021 ; Zhang et al, 2021 ), while frequent reports on fire and explosion of LIBs, due to the flammability of organic electrolytes, raised people’s concerns on their safety ( Zhu et al, 2021 ; Xu and Jiang, 2021). Aqueous rechargeable zinc-ion batteries (ZIBs) with high theoretical capacities (volumetric capacity of 5,855 mA h cm −3 and gravimetric capacity of 820 mA h g −1 ), low cost, and absolute security characteristics are practical alternatives ( Liu et al, 2019 ; Qiu et al, 2019 ; Wu H Y et al, 2021 ).…”