Correlating Structural Properties with Electrochemical Behavior of Non-graphitizable Carbons in Na-Ion Batteries

Abstract

We report on a detailed structural versus electrochemical property investigation of the corncob-derived non-graphitizable carbons prepared at different carbonization temperatures using a combination of structural characterization methodology unique to this field. Non-graphitizable carbons are currently the most viable option for the negative electrode in sodium-ion batteries. However, many challenges arise from the strong dependence of the precursor’s choice and carbonization parameters on the evolution of the carbon matrix and its resulting electrochemistry. We followed structure development upon the increase in carbonization temperature with thorough structural characterization and electrochemical testing. With the increase of carbonization temperature from 900 to 1600 °C, our prepared materials exhibited a trend toward increasing structural order, an increase in the specific surface area of micropores, the development of ultramicroporosity, and an increase in conductivity. This was clearly demonstrated by a synergy of small- and wide-angle X-ray scattering, scanning transmission electron microscopy, and electron-energy loss spectroscopy techniques. Three-electrode full cell measurements confirmed incomplete desodiation of Na + ions from the non-graphitizable carbons in the first cycle due to the formation of a solid–electrolyte interface and Na trapping in the pores, followed by a stable second cycle. The study of cycling stability over 100 cycles in a half-cell configuration confirmed the observed high irreversible capacity in the first cycle, which stabilized to a slow decrease afterward, with the Coulombic efficiency reaching 99% after 30 cycles and then stabilizing between 99.3 and 99.5%. Subsequently, a strong correlation between the determined structural properties and the electrochemical behavior was established.

Exploring hybrid hard carbon/Bi2S3-based negative electrodes for Na-ion batteries

“…In the low voltage region below 100 mV, another longer plateau is observed, resembling the sodium intercalation and pore-filling process in HC. 41 The capacity contributions obtained from the sloping and plateau regions are strongly dependent on the addition of Bi 2 S 3 nanocrystals (Fig. S2 †).…”

Surfactant stabilization of vanadium iron oxide derived from Prussian blue analog for lithium-ion battery electrodes

“…After the initial 10 cycles, capacity begins to fall, and the Coulombic efficiency shows a high scattering in parallel, which indicates side reactions. 39 The initial capacity increase appears likely because of material activation and access to more electrochemically active particles. 40 However, with the lack of a protective layer, when the electrolyte accesses the FVO particles, they are continuously etched and disintegrated, resulting in capacity fading.…”

Review: Insights on Hard Carbon Materials for Sodium‐Ion Batteries (SIBs): Synthesis – Properties – Performance Relationships

“…This may be linked to the variety and accessibility of different wastes, such as trees, plants, and agriculture. Different publications have reported HC anodes obtained from a wide variety of biomass precursors (Figure 3b), including corn cobs, [62,63] lotus, [26] various nut shells, [24,64,65] pine, [66] and different tree woods. [67,68] However, drawbacks, such as the high amount of inorganic impurities, the intrinsic complex structure, low carbon yield, and seasonal/geographical factors, make their use challenging in some cases.…”

“…SAXS (small-angle X-ray scattering) is an interesting tool for investigating the HC texture. [63,177] In particular, it provides valuable information on the closed porosity, as well as other information. Figure 12c presents a typical SAXS profile of HC, where the intensity is a function of a scattering vector (q).…”