Disodium Terephthalate (Na₂C₈H₄O₄) as High Performance Anode Material for Low‐Cost Room‐Temperature Sodium‐Ion Battery

Abstract

In the fi eld of energy storage, lithium (Li)-ion batteries dominate the portable consumer electronic market because of their high energy density. Recently, however, the sodium (Na)-ion battery has again aroused interest for large-scale energy storage due to Na abundance. [1][2][3][4][5][6] Conventionally, the chemistry behind Li-ion and Na-ion batteries involves transition metal elements, [ 4 , 6 ] thus giving rise to problems of cost and environmental concern. Therefore, intensive efforts have been aimed at the development of new Li storage materials shifting from inorganic to organic compounds. [ 7 ] Numerous advantages exist in using organic materials as electrodes for energy storage, such as their tremendous chemical compounds, the tuning of the redox potential in a wide range, possible multi-electron reactions, the abundant resources from biomass, and ease in recycling. [7][8][9][10][11][12] A number of Li-containing organic compounds have been demonstrated to have high lithium storage capacity, good cycleability, and moderate rate capability, making them promising applications in Li-ion batteries. [ 7 , 10-12 ] However, there is no report on the use of such organic compounds in Na-ion batteries.In this contribution, a carboxylate-based organic material, disodium terephthalate (Na 2 C 8 H 4 O 4 ), is introduced as a novel anode material for low-cost room-temperature Na-ion batteries. To the best of our knowledge, this is the fi rst time that an organic compound is reported for the use as an anode material for Na-ion batteries. This material exhibits a low Na insertion voltage at 0.29 V vs. Na + /Na and a high reversible capacity of 250 mAh/g with excellent cycleability. It is found that Na storage performance can be further improved by a thin layer of Al 2 O 3 coating on the Na 2 C 8 H 4 O 4 electrode surface.Scheme 1 shows the molecular structure of Na 2 C 8 H 4 O 4 . The existence of two carbonyl groups allows for the insertion and deinsertion of two Na ions, corresponding to a theoretical capacity of 255 mAh/g. In order to confi rm the purity of the as-received Na 2 C 8 H 4 O 4 , nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) measurements were performed. Both NMR and FTIR results as shown in Figures S1 and S2 reveal the high purity of the sample. The Na 2 C 8 H 4 O 4 has an orthorhombic structure and can be indexed in space group Pbc21, according to JCPDS card No. 00-052-2146 ( Figure S3). [ 13 ] The lattice constants of Na 2 C 8 H 4 O 4 are a = 3.5480 Å, b = 10.8160 Å, and c = 18.9943 Å, and its lattice volume is V = 728.92 Å 3 . The XRD pattern of as-received Na 2 C 8 H 4 O 4 showed preferentially oriented (006) and (008) planes. Thus, refi ning the structure is diffi cult. This can be evidenced by the scanning electron microscopy (SEM) image in Figure 1 b, where the as-received sample is shown to have a fl ake-like structure with very large size near 100 μ m. To reduce the particle size and increase electronic conductivity, the sample wa...

Aromatic porous-honeycomb electrodes for a sodium-organic energy storage device

“…6), which are performed as state-ofthe-art high-performance cathodes for Na-ion batteries, and are much higher than for other intercalation compounds such as fluorophosphates 12,13 , NASICONs 14 and olivines 15 . By combing state-of-the-arts anodes 27,56,57 , and electrolytes, such as ionic liquids 58 or NaPF 6 in EC:PC (ref. 59), the safety problem, which is one of the most important points for any practical technology, of a sodium-organic energy storage device could be improved.…”

“…5). Another even more effective approach to improving affordability is to replace the current metal-based electrodes with organic materials [19][20][21][22][23][24][25][26][27] that are more abundant in nature. Since the advent of conductive polymers 28 and reversible redox polymers 22 , a large number of p-, n-and bipolar organic electrodes have been investigated for energy storage devices due to their low-cost and possible applications in flexible plastic batteries 21 .…”

“…Since the advent of conductive polymers 28 and reversible redox polymers 22 , a large number of p-, n-and bipolar organic electrodes have been investigated for energy storage devices due to their low-cost and possible applications in flexible plastic batteries 21 . Although there is a long history of research in sodium-based energy storage devices, there have been only a few reports of organic materials applied to rechargeable sodium batteries, for example, polyparaphenylene and sodium terephthalate 23,24,27 , and often they are only suitable as the anode. Finding a new, suitable group of organic materials for use as cathodes in sodium batteries could stimulate the development of sodium-based energy storage devices and meet the requirement of next-generation batteries, namely high-specific energy and power, and most importantly, affordability.…”

Direct atomic-scale confirmation of three-phase storage mechanism in Li4Ti5O12 anodes for room-temperature sodium-ion batteries

“…In contrast, very few anode materials were reported to be viable 5,20 . Among the limited number of anode materials 13,[21][22][23][24][25][26][27][28][29] , hard carbon is the only candidate possessing both high storage capacity and good cycling 13,23 . However, as the sodium storage voltage in hard carbon is relatively low and near zero versus Na þ /Na, this would result in sodium metal deposition on its surface in an improper operation or during fast charging, giving rise to major safety concern.…”

Recent Advances in the Use of Carbonyl Compounds as Active Components in Organic-Based Batteries

“…The loss of resonance or aromaticity in the core of the molecules brings the redox reaction to very low potential. The first example of carboxylates in organic sodium-ion batteries (OSIBs) was disodium terephthalate (Na2TP) which was simultaneously reported by two research groups [53,54]. Na2TP contains two carbonyl groups that allow inserting or extracting Na-ions, corresponding to a theoretical capacity of255 mAhg -1 .…”