Poly(anthraquinonyl imide) as a high capacity organic cathode material for Na-ion batteries

Abstract

Redox-active organic imides are potential alternatives to the transition-metal based cathodes for material-sustainable and environment-friendly Na-ion batteries; however, their poor cyclability remains a challenge for battery applications. To address this issue, we use a redox-active anthraquinone to link the small carbonyl molecules to obtain a conjugated polymer with multiple redox-active centers. Herein, we synthesize four cathode-active poly(anthraquinonyl imide)s (PAQIs) from pyromellitic dianhydride (or 1,4,5,8-naphthalenetetracarboxylic dianhydride) and 1,4-diaminoanthraquinone (or 1,5-diaminoanthraquinone). The as-prepared PAQI materials exhibit a high reversible capacity of 190 mAh g −1 and a stable cyclability with 93% capacity retention over 150 cycles, suggesting a possible use of these organic cathode materials for high capacity Na-ion batteries. 11 denoted in different colors. As seen in Fig. 5a, the main CV feature of PAQI-B14 (red curve) emerges as two pairs of redox peaks with similar areas at 1.42/1.58 and 1.85/2.15 V, resembling very much the CV patterns of PAQS. 8 As a reversible two-electron transfer can occur for both of pyromellitic diimide (PMDI, Fig. S2, ESI) and AQ groups,8,14,15,21,22 it is speculated that the two pairs of redox peaks of PAQI-B14 are ascribed to the stepwise two-electron transfer for both of the PMDI and AQ units. A detailed examination of the curve indicates that a shoulder oxidation peak appears at 1.95 V, which is originated from the PMDI unit. On the other hand, PAQI-B15 shows similar CV pattern (green, Fig. 5a) as PAQI-B14, but its redox peaks are better separated in the higher potential region. Hence, in the case of PAQI-B15, the redox potentials of PMDI unit are 1.35/1.65 and 1.8/2.0 V, and those of AQ unit are 1.35/1.65 and 1.9/2.25 V. Similarly, the redox potentials of PAQI-N15 can be determined. As shown in Fig. 5b, four pairs of redox peaks are observed for PAQI-N15 (orange curve) at 1.42/1.78, 1.65/2.0, 2.0/2.25, and 2.12/2.40 V. Based on the data of NTCDI 12 and AQ groups, 8 the CV peaks at 1.65/2.0 and 2.12/2.40 V can be attributed to the redox reactions of NTCDI groups, and the peaks at 1.42/1.78 and 2.0/2.25 V are given rise by the AQ groups. In comparison, PAQI-B15 and PAQI-N15 show a larger separation in the oxidation and reduction peaks, i.e, a larger polarization, than PAQI-B14 and PAQI-N14, respectively, implying that PAQI-B14and PAQI-N14 undergo their redox reactions more reversibly and easily than PAQI-B15 and PAQI-N15, most likely due to their lower steric hindrance for Na + intercalation/deintercalation. 24

Advanced Organic Electrode Materials for Rechargeable Sodium‐Ion Batteries

“…Wu and co-workers took the advantages of imide (high stability) and quinone (high capacity), designing two copolymers with high theoretical capacities of 255 mA h g −1 (No. [68] Another approach is developing three dimensional polyimides with porous structures (No. 49), respectively.…”

Synthesis and Exploration of Ladder‐Structured Large Aromatic Dianhydrides as Organic Cathodes for Rechargeable Lithium‐Ion Batteries

“…As shown in Figure c, both NDA‐4N and PDA‐4N show good thermal stability under a nitrogen atmosphere. The results indicate a significantly improved inherent stability of the two large, aromatic ladder‐structured compounds as compared with single NDA and PDA units . More specifically, NDA‐4N starts to decompose at about 520 °C, while PDA‐4N with a larger backbone structure shows a better thermal stability with a decomposition temperature close to 600 °C.…”

Advanced Cathode Materials for Sodium‐Ion Batteries: What Determines Our Choices?

“…Metal-free cathodes Na 2 C 6 O 6 [196] 2.3 V 190 (0.1C, 1.6-2.8 V) 95%, 100 cycles Na 6 C 6 O 6 [197] 2.3 V 173.5 (50 mA g −1 , 1-3 V) 90%, 1500 cycles SSDC [198] 2 V 105 (2 A g −1 , 0.1-2.5 V) 70%, 400 cycles C 6 Cl 4 O 2 /CMK [201] 2.72 V 161 (10 mA g −1 , 2-3.5 V) 67%, 20 cycles PTCDA-PIs [205] 2.2 V 148 (10 mA g −1 , 1.6-3.6 V) 87.5%, 5000 cycles poly(anthraquinonyl imide)s [207] 2. poor cycling stability and rate performance due to the inevitable lattice expansion and multiphase transitions. Phosphates can display a good cycling stability, but they are restricted by their low specific capacity of 110 mA h g −1 , as well as their low energy density around 350 W h kg −1 , resulting from the high molecular weight and sluggish Na + -insertion/extraction kinetics.…”

“…[206] Recently, Xu et al synthesized cathode-active poly(anthraquinonyl imide)s (PAQIs) from redox-active carbonyl molecules, such as 1,4-diaminoanthraquinone (NTCDA) with 2,6-diaminoanthraquinone (26DAAQ). [207] The obtained π-conjugated PAQIs with multiple redox-active centers demonstrated a high reversible capacity of ≈190 mA h g −1 and a cycling stability (93% retention after 150 cycles), suggesting potential application of such polymer cathode materials in SIBs. [207] …”

“…[207] The obtained π-conjugated PAQIs with multiple redox-active centers demonstrated a high reversible capacity of ≈190 mA h g −1 and a cycling stability (93% retention after 150 cycles), suggesting potential application of such polymer cathode materials in SIBs. [207] …”