Efficient K‐Storage of Fe‐Coupled Organic Molecule Anode in Ether‐Based Electrolytes

Abstract

Given these advantages of widely designable structures and environmentally friendly characteristics, organic electrode materials (OEMs) are considered to be promising electrode materials for alkaline metal-ion batteries. However, their large-scale application is hampered by insufficient specific capacity and rate performance. Here, Fe 2 + is coupled to the anhydride molecule NTCDA to form a novel K-storage anode Fe-NTCDA. In this way, the working potential of Fe-NTCDA anode is reduced, which makes it more suitable to be used as an anode material. Meanwhile, the electrochemical performance is significantly improved due to the increase in K-storage sites. Moreover, electrolytes regulation is implemented to optimize the K-storage behavior, resulting into a high specific capacity of 167 mAh/g after 100 cycles at 50 mA/g and 114 mAh/g even at 500 mA/g in the 3 M KFSI/ DME electrolytes.

Hard Carbon Anode Synthesized by an In Situ Porous Strategy for Advanced Potassium-Ion Batteries

“…It can be clearly seen that the content of O-I has no obvious change, while the content of O-II decreases and the content of O-III increases for P-HC. This may be due to the introduction of KOH promoting the breaking of the C–O–C bond and the formation of –COOK, which leads to the reduction of C–O–C bond content in the precursor itself . Meanwhile, the subsequent generation of K 2 CO 3 also has a catalytic cracking effect on the C–O–C bond generated by carbonization, causing the C–O–C bond to break and release CO 2 and CO .…”

Reliable Organic Carbonyl Electrode Materials Enabled by Electrolyte and Interfacial Chemistry Regulation

“…For example, the overpotential of Fe-NTCDA (NTCDA: 1,4,5,8-naphthalenetetracarboxylic dianhydride) in 1 M KFSI/DME for the second cycle is about 0.70 V, which increases over 0.95 V after 100 cycles (Figure 2c). 44 In contrast, the Fe-NTCDA electrode in 3 M KFSI/DME has a lower overpotential of 0.82 V after 100 cycles. The reduced polarization of Fe-NTCDA is attributed to the aggregate (AGG) solvation structure, which is dominant in 3 M KFSI/ DME (Figure 2d).…”

“…In addition, the salt concentration also influences the potential of carbonyl electrode materials through the aspect of kinetics. For example, the overpotential of Fe-NTCDA (NTCDA: 1,4,5,8-naphthalene­tetracarboxylic dianhydride) in 1 M KFSI/DME for the second cycle is about 0.70 V, which increases over 0.95 V after 100 cycles (Figure c) . In contrast, the Fe-NTCDA electrode in 3 M KFSI/DME has a lower overpotential of 0.82 V after 100 cycles.…”