Plasma-promoted surface regulation of a novel integrative carbon network for boosting the long-cycle capability of sodium-ion storage

Non-negligible Influence of Oxygen in Hard Carbon as an Anode Material for Potassium-Ion Batteries

“…The surface-controlled K + storage mechanism of the HC-600 electrode at different charge states is further evidenced by ex situ XPS measurements (Figure a–f). The intensity of the CO peak (533.9 eV) decreases accompanied by the reversible reaction of CO + K + + e – ↔ C–O–K, similar to Na + , ,, resulting in the contribution of the surface pseudocapacity. The C–O–K generation is also observed in K 2s of 0.01 V states from the additional peak at 378.5 eV (Figure e,f).…”

“…On the one hand, the decrease in HC interlayer spacing hinders the transport of K + . On the other hand, the reduction of the active sites for potassium-ion storage is caused by decreased CO bonds in surface oxygen-containing functional groups with increased carbonization temperature. ,, These two reasons result in the variation in the rate performance of HCs.…”

“…Based on the above analysis, HC-600 possesses more active sites for K + storage by adsorption due to abundant CO groups and micropores, thus improving the electrochemical performance of PIBs. The higher CO content in HC-600 enhanced the reversible pseudocapacity K + storage because of the reversible reaction. , With the increase in annealing temperature, the structure of HC-1000 is more ordered and the defects and surface oxygen-containing functional groups decrease, leading to fewer active sites for K + adsorption. In addition, HC-1000 with smaller interlayer spacing causes a longer path for K + diffusion and difficulties for K + insertion between interlayers, resulting in unsatisfactory electrochemical performance.…”

Hard carbon for sodium-ion batteries: progress, strategies and future perspective

“…With an increase in the pyrolysis temperature, the ICE increases as a result of the decreased amount of defects, and thus lowers the irreversible capacity. 42–86 In summary, high-temperature pyrolysis treatment is a necessary step to ensure the graphitization structure of the final products. However, different pre-treatments are applied to achieve desirable performance according to different precursors.…”

“…Another feasible and rapid method of the plasma-assisted chemical vapor deposition process was proposed at a relatively low carbonization temperature (900 °C) by Li and coworkers. 66 As a consequence, a novel integrative carbon network material (ICN) was successfully prepared on a large scale, as presented in Fig. 10d .…”