Polyanthraquinone as a Reliable Organic Electrode for Stable and Fast Lithium Storage

Abstract

In spite of recent progress, there is still a lack of reliable organic electrodes for Li storage with high comprehensive performance, especially in terms of long-term cycling stability. Herein, we report an ideal polymer electrode based on anthraquinone, namely, polyanthraquinone (PAQ), or specifically, poly(1,4-anthraquinone) (P14AQ) and poly(1,5-anthraquinone) (P15AQ). As a lithium-storage cathode, P14AQ showed exceptional performance, including reversible capacity almost equal to the theoretical value (260 mA h g(-1); >257 mA h g(-1) for AQ), a very small voltage gap between the charge and discharge curves (2.18-2.14=0.04 V), stable cycling performance (99.4% capacity retention after 1000 cycles), and fast-discharge/charge ability (release of 69% of the low-rate capacity or 64% of the energy in just 2 min). Exploration of the structure-performance relationship between P14AQ and related materials also provided us with deeper understanding for the design of organic electrodes.

Polyanthraquinone‐Based Organic Cathode for High‐Performance Rechargeable Magnesium‐Ion Batteries

“…Coincidentally, a recent account reporting the polyanthraquinone system for lithiumion batteries was recently published while we are summarizing our quinonyl polymer structure variation studies for the magnesium batteries, and the strategies were developed in order to solve the same problem. [15] Two anthraquinone-based polymers, 26PAQ and 14PAQ, aiming at improving the capacity retention for advanced magnesium-ion batteries, were synthesized according to the modified literature procedures (see the Supporting Information for details). [16] As shown in Figure 2, both the two polymers have shown excellent chemical reversibility in the cyclic voltammogram (CV) measurements using the 0.3 m Mg(HMDS) 2 -4MgCl 2 /THF electrolyte.…”

“…A similar small polarization was also observed for 14PAQ in Li-ion batteries, which was attributed to the much smaller HOMO-LUMO (highest occupied molecular orbital-lowest unoccupied molecular orbital*) gap in the molecular level compared to other polyanthraquinonyl derivatives. [15] In addition to the excellent cycling performance at a 0.5 C rate, the rate performance of wileyonlinelibrary.com each current rate). As shown in Figure 4b, the demonstrated cycling stability further highlights the great potential 14PAQ as high-rate and long-term cycling cathode material for rechargeable magnesium-ion batteries.…”

A novel quinone-based polymer electrode for high performance lithium-ion batteries

“…Recently, polymers containing redox-active carbonyl groups (C=O) have been thoroughly investigated [12,[17][18][19][20][21][22][23][24][25][26][27]. Especially, quinones are regarded as the most promising types ABSTRACT Designing of high electrochemical performance organic electrode materials has attracted tremendous attention.…”

“…Although many small molecules have been synthesized and investigated as the electrode materials for LIBs, the reported electrochemical performances in terms of both specific capacity and cycling stability were still far away from the practical applications due to the serious dissolution issue [10][11][12]. Therefore, it is urgent to design novel organic compounds that can overcome the LETTERS of organic electrode materials [12,18,20,21,23,24]. The redox mechanism of the electrochemically reactive carbonyl groups is well explained by the enolation process between the lithium ions and the carbonyl groups.…”

“…Apart from the carbonyl bonds that provided the reactive centers for the redox reactions, the thioether bonds was found to greatly enhance the conductivity of the electrode and thus leaded to a high stability of the electrode. More recently, polyanthraquinone (PAQ) and lithium salt of poly(2,5-dihydroxy-p-benzoquinonyl sulfide) (Li 2 PDHBQS) were also discovered to have the ability to deliver excellent cycling stability after ultra-long charge-discharge cycles [18,20]. The extraordinary electrochemical results of these polymers indicated that quinone-based polymers with the thioether bond could effectively improve the redox reactivity as well as prevent the unwanted dissolution of the organic compounds.…”