Electrochemically prelithiated carbon anodes with regulated Na-ion intercalation behaviours for advanced sodium-ioni energy storage devices

Abstract

Sodium-ion capacitors (SICs) have long been pursued as the economically favorable alternatives to their well-developed lithium-ion counterparts. However, their commercialization suffers from the immature pre-sodiation technology in existence, primarily due...

Revealing the Effect of the Microstructure on Potassium Storage Behavior in a Two-Dimensional Mesoporous Carbon Anode

“…According to the working mechanisms of metal-ion capacitors (including Li + , Na + , K + , and so on), the prevailing capacity mismatch issue between the anode and the cathode results in the capacity performance of metal-ion capacitors depending on the capacitive cathode. − As expected, the capacitive performance of PICs based on the 2D-MCM-1500 anode is better than that of PICs based on the 2D-MCM-1100 anode. The above results emphasize the importance of developing anode materials with high capacity-contribution ratio from the low potential region, which is consistent with the mainstream view on fabricating Li/Na-ion capacitors and batteries with high voltages and high capacity by exploring the anode materials with low redox potentials and large theoretical capacity. ,,,− …”

“…23,24,36,39 Coulombic efficiency of carbon and carbon-related anodes could be solved by the chemical or electrochemical prepotassiation processes. [8][9][10]44 These GCD curves feature a triangular shape without the voltage plateau in a wide work potential region, which is a common characteristic for all hard carbons with highly porous structures and/or heteroatom doping properties. 25,27,31,45−49 A closer examination on the discharge curves of these 2D-MCM-x electrodes showed that with increasing annealing temperature, the capacity contributed from the sloping curve lower than 0.25 V (vs K + /K) gradually increased, while the capacity contributed from the sloping curve higher than 0.25 V exhibited a reverse trend (Figure 4b).…”

“…2D-MCM- x samples show large irreversible capacity during the first cycle, primarily due to the formation of the SEI layer and irreversible side reactions on the surface of the 2D-MCM- x electrode, which is consistent with CVs’ observation. Recent studies showed that the low Coulombic efficiency of carbon and carbon-related anodes could be solved by the chemical or electrochemical prepotassiation processes. − , These GCD curves feature a triangular shape without the voltage plateau in a wide work potential region, which is a common characteristic for all hard carbons with highly porous structures and/or heteroatom doping properties. ,,,− A closer examination on the discharge curves of these 2D-MCM- x electrodes showed that with increasing annealing temperature, the capacity contributed from the sloping curve lower than 0.25 V (vs K + /K) gradually increased, while the capacity contributed from the sloping curve higher than 0.25 V exhibited a reverse trend (Figure b). These variation trends on capacity contributions seem to coincide with increasing graphitic ordering and reducing heteroatom content of the 2D-MCM- x samples.…”

A fundamental understanding of structure evolution in the synthesis of hard carbon from coal tar pitch for high-performance sodium storage

“…In the first scan, two irreversible reduction bands were observed at 0.7–1.5 V and 0.2–0.6 V, which could be attributed to the irreversible electrochemical process and solid electrolyte interface (SEI) formation. 73 The broad cathodic peak at 0.2–2.0 V and the sharp peak below 0.1 V were attributed to the slope capacity and plateau capacity, respectively. 74 It could also be observed that the peak intensity for the POP3-1200 electrode below 0.1 V was the highest among all the CTP-derived carbon electrodes, signifying its best electrochemical reaction activity at low potential.…”