Organic Lithium-ion Batteries Research Articles

High Capacity and Energy Density Organic Lithium‐Ion Battery Based on Buckypaper with Stable π‐Radical

Owing to an increasing demand on high performance and rare-metal free energy storage systems, organic rechargeable battery has attracted much attention. To increase the capacity of the whole battery, we have fabricated coin-type buckypaper cells composed of a trioxotriangulene neutral radical derivative (H3 TOT) and single-walled carbon nanotubes as a cathode and lithium metal plate as an anode without current collector. The cells exhibited a stable charge-discharge behavior even at a 90 wt % H3 TOT content with a high-rate performance of 10 C originating from high electrical conductivity of H3 TOT. Furthermore, based on the four-stage redox ability of H3 TOT, the H3 TOT 90 wt % cathode showed a high capacity of approximately 260 mAh g-1 and a high energy density of 546 Wh g-1 . In view of the simple fabrication of the cathode and excellent performance, TOT-based buckypaper will open a new strategy for the flexible cells for next-generation energy storages.

A perylene-based aromatic polyimide with multiple carbonyls enabling high-capacity and stable organic lithium and sodium ion batteries

We have synthesized a perylene-based aromatic polyimide (PI) through the polycondensation of perylene dianhydride with a 2,6-DAAQ. The battery cells with the PI cathode exhibited high discharge capacities of 209 mA h g−1 (Li+/Li) and 207 mA h g−1 (Na+/Na) at 200 mA g−1.

Thionated benzo[c]thiophen-1(3H)-one as an organic cathode with high capacity for sulfur-rich all organic lithium-ion batteries

Combining two thionation strategies, a novel cathode material benzo[c]thiophen-1(3H)-thione (DPTTO) was prepared, which showed good battery performances in half-cell and sulfur-rich all organic lithium-ion batteries.

The Progress and Prospect of Tunable Organic Molecules for Organic Lithium-Ion Batteries.

Compared to inorganic electrodes, organic materials are regarded as promising electrodes for lithium-ion batteries (LIBs) due to the attractive advantages of light elements, molecular-level structural design, fast electron/ion transferring, favorable environmental impacts, and flexible feature, etc. Not only specific capacities but also working potentials of organic electrodes are reasonably tuned by polymerization, electron-donating/withdrawing groups, and multifunctional groups as well as conductive additives, which have attracted intensive attention. However, organic LIBs (OLIBs) are also facing challenges on capacity loss, side reactions, electrode dissolution, low electronic conductivity, and short cycle life, etc. Many strategies have been applied to tackle those challenges, and many inspiring results have been achieved in the last few decades. In this review, we have introduced the basic concepts of LIBs and OLIBs, followed by the typical cathode and anode materials with various physicochemical properties, redox reaction mechanisms, and evolutions of functional groups. Typical charge-discharge behaviors and molecular structures of organic electrodes are displayed. Moreover, effective strategies on addressing problems of organic electrodes are summarized to give some guidance on the synthesis of optimized organic electrodes for practical applications of OLIBs.

Disodium‐Substituted Tetrahydroxybenzoquinone Salt as an Organic Electrode for High‐Performance Lithium‐Ion Batteries

Organic lithium‐ion batteries (OLIBs) are desirable alternatives for next‐generation energy storage systems in terms of their low‐cost, eco‐friendliness, and structural diversity. However, the intrinsic plagues such as electrical insulation, high dissolution in liquid electrolytes, and low energy densities significantly restrict their widespread applications. Herein, a para‐disodium‐2, 5‐dihydroxy‐1, 4‐tetrahydroxybenzoquinone (p‐DSDHBQ) microcone is prepared through a simple synthetic method using the raw glyoxal (30% C2H2O2, aq) solution. The as‐obtained p‐DSDHBQ microcone demonstrates a high reversible capacity of 253 mA h g−1 at 0.1 C and retains a capacity of 199.9 mA h g−1 after 100 cycles. Moreover, the organic sodium salt exhibits superior rate performance (111 mA h g−1 at 20 C) and long‐term cycling stability (135.5 mA h g−1 at 10 C after 1000 cycles). Morphological observation, electrochemical impedance analysis, and cyclic voltammogram (CV) curves at different rates also provide insight to the advantage of phenolate sodium (ONa) groups. More interestingly, the negligible structural change during discharging/charging can be in charge of an excellent cyclic stability. Therefore, this work might provide a great opportunity to explore organic materials for LIB applications.

Organic Liquid Crystals as Single-Ion Li+ Conductors.

The development of new materials for tomorrow's electrochemical energy storage technologies, based on thoroughly designed molecular architectures is at the forefront of materials research. In this line, we report herein the development of a new class of organic lithium-ion battery electrolytes, thermotropic liquid crystalline single-ion conductors, for which the single-ion charge transport is decoupled from the molecular dynamics (i. e., obeys Arrhenius-type conductivity) just like in inorganic (single-)ion conductors. Focusing on an in-depth understanding of the structure-to-transport interplay and the demonstration of the proof-of-concept, we provide also strategies for their further development, as illustrated by the introduction of additional ionic groups to increase the charge carrier density, which results in a substantially enhanced ionic conductivity especially at lower temperatures.

Improved gravimetric energy density and cycle life in organic lithium-ion batteries with naphthazarin-based electrode materials

Replacing the scarce metal-based positive electrode materials currently used in rechargeable lithium ion batteries with organic compounds helps address environmental issues and might enhance gravimetric electrochemical capacity. The challenge has been to find organic materials with both high capacity and long-cycle life. Here, we study the naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) skeleton as a high capacity candidate electrode for lithium-ion batteries, showing a multielectron-transfer type redox reaction. We also use electron energy-loss spectroscopy to reveal the reaction stoichiometry during charge/discharge processes. While the lithium salt of naphthazarin itself helped deliver a high initial capacity, its cycle-life was not satisfactory. Instead, a newly synthesized naphthazarin-dimer shows a lengthened cycle-life without sacrificing the initial high capacity of 416 mAh g−1 and energy density of 1.1 Wh g−1.

Nanostructured strategies towards boosting organic lithium-ion batteries

Pursuing material development for next-generation batteries, organic electrode materials have shown great potential for lithium-ion batteries. However, their widespread adopting is plagued by intrinsic problems such as poor electronic conductivity, high dissolution inside electrolytes and unstable chemical peculiarity. Recently, nanostructured-strategies promoted organic electrodes with exotic properties for enhancing electron and ion transport together with the stability during electrochemical process, have received increasing attention and have been extensive applied in boosting the organic lithium-ion based energy storage. In this review, we summarize the applications of nanostructures to improve the performance of both organic anodes and cathodes, including (i) nanoscale design of zero-dimensional organic electrode materials, (ii) strategies of one-dimensional nanostructured organic electrode materials, (iii) construction of two-dimensional nanosized organic composite electrodes, and (iv) three-dimensional exploration of nanosized organic electrodes. We hope to stimulate high-quality applied research on understanding and handling the relationship between the nanostructure and performance of organic lithium-ion batteries that might speed up the commercialization of organic lithium ion batteries.

High performance lithium-ion batteries with pillar[5]quinone/ion-liquid system

Abstract The capacity of cathode is a short slab issue of lithium-ion batteries (LIBs). Organic quinone cathode materials with high theoretical capacities could effectively solve the problem. Here, pillar[5]quinone (P5Q) with high theoretical capacity of 446 mAh g−1 is chosen as the cathode, while it is puzzled over fast dissolution rate in traditional organic electrolytes. Recently, ionic liquids have been reported the weak dissolution towards organic compounds. At the same time, their peculiarities of non-volatilization and non-combustibility could reduce the safety risk of using traditional organic electrolytes in LIBs. In this work, LIBs combined with LiPF6/[PY13][TFSI] (Lithium Hexafluorophosphate/N-methyl-N-propylpyrrolidiniumbis(trifluoromethanesulfonyl)amide) electrolyte and P5Q cathode show excellent electrochemical performance, principally reflected in stable cycling performance (maintain at 284 mAh g−1 at 0.2 C current density after 200 cycles with capacity retention of 70%) and high rate property (reach 220 mAh g−1 at 2 C). This strategy would further realize the practical application of organic LIBs.

Superior anodic lithium storage behavior of organic pigment 2,9-dimethylquinacridone

Organic anode materials are of great importance for the development of lithium ion batteries (LIBs) with less reliance on inorganic minerals. In this work, it is found that 2,9-dimethylquinacridone (2,9-DMQA), an organic pigment, can have excellent electrochemical performances when serving as the anode material in LIBs. 2,9-DMQA based LIB anode manifests a high specific capacity of 1150 mAh g−1 at 0.1 A g−1. Even at a high current density of 5.0 A g−1, the capacity of 2,9-DMQA can still be retained at ~385 mAh g−1, outperforming many recently reported LIB anodes. The results from experiments and calculation suggest that 2,9-DMQA can reversibly associate with ~22Li+, corresponding to a theoretical capacity of 1732 mAh g−1. Additionally, the full-cell with 2,9-DMQA as anode and LiCoO2 as cathode can deliver the energy and power density of 325.8 Wh kg−1 and 1137.1 W kg−1, respectively, which are better than most of recently reported full-cells, implying the intriguing potential of the 2,9-DMQA anode in organic LIBs.

Carbonyl Bridge-Based p-π Conjugated Polymers as High-Performance Electrodes of Organic Lithium-Ion Batteries.

Organic redox compounds have shown promising potential as electrode materials for lithium-ion batteries. Polymerization is an effective and feasible method to prevent rapid capacity decay. However, present conjugated polymers and nonconjugated polymers have their own limitations to constructing stable and high-performance electrodes. Herein, we report a novel polyimide NDI-O, which is connected by carbonyl bridges. The NDI-O is a p-π conjugated polymer that exhibits a high gravimetric energy density of 542 W h kg-1 and an ultrahigh power density of 14,000 W kg-1 due to its intriguing electronic properties. The combination of molecular electrostatic potential calculations and ex situ technologies reveals the lithium-ion storage mechanism during the charge and discharge processes. The orbital distribution calculations and electrochemical impedance spectroscopy tests have been shown to verify the excellent kinetic properties of NDI-O. This work expands the scope of polymers applied for LIBs and provides new methods to construct high-performance electrode materials for sustainable batteries.

Carbonized cotton fiber supported flexible organic lithium ion battery cathodes

Carbonized cotton fibers (CCFs) were prepared by the carbonization of commercial cottons at 700, 800 and 900 °C. The following characterizations indicated that the properties of the obtained CCFs could be effectively tuned by the carbonization temperatures. Containing both high conductivity and high aspect ratio, the CCFs could be used as the conductive agents for the construction of the integrated organic cathodes in lithium ion batteries (LIBs). With the optimized ratio of CCF from 900 °C, the organic LIB cathodes showed a high specific capacity of 135 mA h g−1 at a current density of 0.05 A g−1 and an impressive cyclizing stability by keeping 90.5% of the highest capacity value after 500 cycles at 0.5 A g−1. The good mechanical stability of the CCF supported organic cathode enabled the further fabrication of flexible LIBs, which manifested stable performances at various bent states, confirming the potentials of CCFs in flexible energy storage devices.

An acid-assisted vacuum filtration approach towards flexible PDI/SWCNT cathodes for highly stable organic lithium ion batteries

An acid-assisted vacuum filtration approach is developed in this work to fabricate perylene diimide (PDI) and single wall carbon nanotube (SWCNT) based organic lithium ion battery (LIB) cathodes by using concentrated sulfuric acid (H2SO4) as the solvent. PDI and SWCNT can be readily dispersed in H2SO4 by the protonation of their aromatic frameworks, thus rendering the effective combination of them in the acidic solution. The resulting PDI/SWCNT films are highly appealing flexible cathodes for LIBs by associating the intriguing electrochemical activity of PDI with the excellent electric conductivity and mechanical stability of SWCNT. Either with lithium foils or pre-lithiated carbon clothes as the anodes, the LIBs with PDI/SWCNT cathodes can deliver highly stable electrochemical performances in terms of rate capability and cycling stability. The PDI/SWCNT cathodes also have very good mechanical stability, enabling the LIBs based on them to reserve the battery performances at different bending states. The excellent electrochemical stability of the PDI/SWCNT cathodes is attributable to the acidic solution based processing method, which is expected to be expanded in the electrode fabrication of various organic secondary batteries with π-conjugated components.

Surface controlled pseudo-capacitive reactions enabling ultra-fast charging and long-life organic lithium ion batteries

To develop ultra-fast charging and long-life lithium ion batteries, a surface-controlled pseudo-capacitive reaction mechanism for organic lithium ion batteries is developed based on a coaxial nanocomposite of an active anthraquinone-based covalent organic framework and CNTs.

Intermolecular channel expansion induced by cation-π interactions to enhance lithium storage in a crosslinked π-conjugated organic anode

The design and synthesis of novel π-conjugated polymers receive tremendous attention in electrochemical energy storage. We report a lithium-doped crosslinked π-conjugated polymer, PTAT@LiCl, with excellent electrochemical performance as an anode material for lithium ion batteries (LIBs). Benefiting from a wider range of intermolecular channel caused by cation-π interaction inducing lithium ion insert into polymer network, the prepared PTAT@LiCl shows high capacity (892 mAh g−1, 100 mA g−1), excellent rate performance (200 mAh g−1, 4C), and outstanding cycle life (500 cycles). This work provides a new insight into the performance enhancement of organic LIBs through noncovalent cation-π (Li+-π) interaction between lithium ions and large π-conjugated aromatic ring, which are meaningful for the potential application of LIBs.

Cost-Effective Biomass Carbon/Calix[4]Quinone Composites for Lithium Ion Batteries.

Searching for new cheap encapsulating materials to decrease the solubility of organic small molecules as the cathode materials in electrolytes and improve the performance of organic lithium-ion batteries (LIBs) is very important and highly desirable. In this research, we found that a novel cheap biomass carbon (named as PPL), prepared by pyrolyzing calyxes of Physalis Peruviana L, can efficiently encapsulate calix[4]quinone to form composites, which can be used as cathodes in LIBs. The initial discharge capacity of the as-fabricated battery was 437 mAh g-1 and could maintain 228 mAh g-1 after 100 cycles. Even at 1 C, the discharge capacity was still 217 mAh g-1 .

Two π-Conjugated Covalent Organic Frameworks with Long-Term Cyclability at High Current Density for Lithium Ion Battery.

Organic lithium ion batteries (LIBs) are considered as one of the next-generation green electrochemical energy storage (EES) devices. However, obtaining both high capacity and long-term cyclability is still the bottleneck of organic electrode materials for LIBs because of weak structural and chemical stability and low conductivity. Covalent organic frameworks (COFs) show potential to overcome these problems owing to its good stability and high capacity. Herein, the synthesis and characterization of two π-conjugated COFs, derived from the Schiff-base reaction of 2,4,6-triaminopyrimidne (TM) respectively with 1,4-phthalaldehyde (PA) and 1,3,5-triformylbenzene (TB) by a mechanochemical process are presented. As anode materials for LIBs, the COFs exhibit favorable electrochemical performance with the highest reversible discharge capacities of up to 401.3 and 379.1 mAh g-1 at a high current density (1 A g-1 ), respectively, and excellent long-term cyclability with 74.8 and 72.7 % capacity retention after 2000 cycles compared to the initial discharge capacities.

Aqueous sodium alginate as binder: Dramatically improving the performance of dilithium terephthalate-based organic lithium ion batteries

The electrochemical performance of a typical carbonyl-based organic electrode material dilithium terephthalate is improved remarkably by using sodium alginate as an aqueous binder. Compared to the conventional poly (vinylidene fluoride) binder, the electrode with sodium alginate as a binder shows significant improvement in electrochemical performance. It delivers a high capacity of 200 mAh g−1 after 100 cycles at 0.1C. Even at 1C, it still remains a capacity of 130 mAh g−1 after 1000 cycles with approximately 100% Coulombic efficiency. Due to its high water solubility, dilithium terephthalate distributes uniformly and is surrounded well by electron conductive carbon in the organic electrode with sodium alginate as aqueous binder. The excellent electrochemical performances result from the faster electron transfer, less interfacial impedance and lower polarization of the organic electrode, because the carboxyl and hydroxyl rich groups of sodium alginate facilitate the ion-transporting in the electrode. This work can provide an approach to enhance the performance of not only organic dilithium terephthalate anode, but also other organic electrode materials in various battery systems.

The impact of vertical π-extension on redox mechanisms of aromatic diimide dyes

Aromatic diimide dyes are an attractive class of redox-active organic molecules for lithium-ion batteries, whose battery performances (stabilities, conductivities and cyclicities) are strongly dependent on the sizes of their π-systems. However, due to the different Clar’s structures possessed, three vertically π-extended aromatic diimides, namely, naphthalene diimide (two one-electron reductions), perylene diimide and terrylene diimide (two one-electron reductions), exhibit different electronic redox mechanisms when served as cathode materials in organic lithium-ion batteries. Herein, we have studied carefully the different electrochemical characteristics of the three aromatic diimides through experimental and theoretical calculations. Their battery present different shape of charge/discharge curves resulting from stability of their reduction state during charge/discharge process. Terrylene diimide shows better cycle and rate capacities than those of naphthalene diimide and perylene diimide, which could be attributed to the more energies released during terrylene diimide combining with lithium ions than those of other two diimides.

Microscopic Behavior of Active Materials Inside a TCNQ-Based Lithium-Ion Rechargeable Battery by in Situ 2D ESR Measurements

Real-time spectroscopic measurements in rechargeable batteries are important to understand the electrochemistry of the batteries at the molecular level and improve relevant functionalities. We have applied in situ two-dimensional (2D) electron spin resonance (ESR) spectroscopy to a well-known organic lithium-ion battery, which is composed of 7,7,8,8-tetracyanoquinodimethane (TCNQ) as the cathode-active material and a lithium metal anode electrode. The TCNQ rechargeable battery is suitable for investigating electrochemistry in the battery in terms of behavior of electron spin at microscopic levels on both the cathode and anode electrodes. We have discussed two-stage oxidation/reduction reactions of TCNQ, Li deposited/stripped process and their resulting dendritic and/or mossy microstructures, clearly elucidating the cause of the cell capacity degradation upon the charge-discharge cycles. The observed in situ ESR spectra showed that the degradation of the cell capacity was due to the elution of the active molecules, which caused the increase of ion conductivity by the substitution of the electrolyte solution for the adsorbed active materials on the conductive carbon surface. To discriminate paramagnetic species during the charge-discharge process, the generalized 2D correlation spectroscopy has been applied to characterize time-dependent in situ ESR spectra. The correlation analysis with in situ ESR helps us identify the paramagnetic species occurring in the battery cell in a straightforward manner.