Ultra-Stable Potassium Ion Storage of Nitrogen-Doped Carbon Nanofiber Derived from Bacterial Cellulose

Abstract

As a promising energy storage system, potassium (K) ion batteries (KIBs) have received extensive attention due to the abundance of potassium resource in the Earth’s crust and the similar properties of K to Li. However, the electrode always presents poor stability for K-ion storage due to the large radius of K-ions. In our work, we develop a nitrogen-doped carbon nanofiber (N-CNF) derived from bacterial cellulose by a simple pyrolysis process, which allows ultra-stable K-ion storage. Even at a large current density of 1 A g−1, our electrode exhibits a reversible specific capacity of 81 mAh g−1 after 3000 cycles for KIBs, with a capacity retention ratio of 71%. To investigate the electrochemical enhancement performance of our N-CNF, we provide the calculation results according to density functional theory, demonstrating that nitrogen doping in carbon is in favor of the K-ion adsorption during the potassiation process. This behavior will contribute to the enhancement of electrochemical performance for KIBs. In addition, our electrode exhibits a low voltage plateau during the potassiation–depotassiation process. To further evaluate this performance, we calculate the “relative energy density” for comparison. The results illustrate that our electrode presents a high “relative energy density”, indicating that our N-CNF is a promising anode material for KIBs.

Insight into a Nitrogen-Doping Mechanism in a Hard-Carbon-Microsphere Anode Material for the Long-Term Cycling of Potassium-Ion Batteries

“…Figure S1: (a S1 Comparison of the electrochemical performance of N-doping hard carbons. References [45][46][47][48] are cited in the supplementary materials.…”

Lignite-based hard carbon high-performance potassium-ion batteries anode

“…Among them, one popular technique for enhancing the reversible capacity, cycling durability, and rate capability of C materials is heteroatom doping. First off, the insertion of heteroatoms like N, S, O, and P can reduce the K + diffusion barrier, increase the number of K + active sites, and enhance the electrical conductance of C materials, all of which are favorable for K + adsorption and migration [14][15][16][17]. Secondly, heteroatom doping can help carbonaceous materials tolerate cubical dilatation during cycling, promote the reversible intercalation of K + , and widen their interlayer spacing [18,19].…”

O-Doping Configurations Reduce the Adsorption Energy Barrier of K-Ions to Improve the Electrochemical Performance of Biomass-Derived Carbon

“…Taking an N atom as an example, its electronegativity is high. When occupying the sites of a carbon lattice, it will change the charge distribution and electronic properties of the carbon structure, induce the generation of additional defects, and promote the ion diffusion rate and electron conduction rate [ 11 ]. Wang et al prepared hemp core-derived carbon with an N content of 8.56% using urea as an N source [ 12 ].…”

“…The following supporting information can be downloaded at: , Figure S1: SEM images of OPDC with different magnifications: (a) ×0.1 k and (b) ×2.0 k. (c) HRTEM and fast Fourier transform (FFT) images of OPDC; Figure S2: Illustration of the calculation for domain thickness; Figure S3: FTIR of OPDC; Figure S4: Contribution ratio of the surface adsorption behavior at the scan rate of 0.7 mV/s; Figure S5: (a) XRD patterns of the OPDC electrode during discharging and charging, (b) the corresponding galvanostatic charge/discharge profile, and (c) Raman spectra of the OPDC electrode during discharging and charging; Figure S6: Schematic diagram of the potassium-ion storage mechanism in the OPDC electrode; Table S1: R SEI and R ct simulated from equivalent circuit analysis at different cycles; Table S2: Comparison of the electrochemical performance between OPDC and partial biomass-derived carbon. References [ 7 , 8 , 9 , 11 , 13 , 16 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ] are cited in supplementary materials .…”