Lithium Organic Batteries Research Articles

Designing anthraquinone-based conjugated microporous polymers with dual-ion storage behavior towards high-performance lithium-organic batteries

Conjugated microporous polymers (CMPs) represent an attractive type of electrode materials for Li-organic batteries (LOBs) systems owing to their high capacity and structure stability in electrolytes. However, CMPs generally suffer from limited electronic conductivity and low output potential. Introduction of functional linkages can endow CMPs with optimized properties besides the electroactive building moieties, which diversify CMPs with satisfying functions. Herein, we prepared two cross-linked anthraquinone-phenylamine CMPs (denoted as TNAQ and TPAQ) as cathodes to build a high-performance LOB. Significantly boosted activity is observed for TNAQ by inserting an arylamine linkage (–NH–) into the CMP skeleton. As expected, LOBs based on TNAQ electrode demonstrates a high discharge capacity of 231 mAh g−1 at 60 mA g−1, high output voltage of 3.7 V (vs Li/Li+), and a high-capacity retention of 81% over 300 cycles at 200 mA g−1, which exceed all anthraquinone-based CMPs electrodes of previously report in LOBs. Our study offers an interesting strategy for CMP-based cathode materials of high-performance advanced LOBs.

Recent Progress and Design Principles for Rechargeable Lithium Organic Batteries

Recent Progress and Design Principles for Rechargeable Lithium Organic Batteries

Integrating multiple redox-active sites and universal electrode-active features into covalent triazine frameworks for organic alkali metal-ion batteries

The advantages of redox-active polymers with multiple redox-active sites and multiple functions stem from the controllability of organic synthesis, which makes it possible to construct universal organic alkali metal-ion batteries. Herein, triazine-bridged hexaazatrinaphthylene polymer (HATN-CTF) was synthesized and then first served as both cathode and anode materials for lithium organic batteries. Interestingly, we realized the controllable construction of crystalline and amorphous HATN-CTF (cHATN-CTF and aHATN-CTF) and give a systematic study to show the superiority of aHATN-CTF resulted from the more abundant active sites and shortened ion diffusion paths. Most importantly, the integration of hexaazatrinaphthylene core and peripheral triazine moieties endows aHATN-CTF with abundant active centers (CN and CC groups), the ability to absorb cations and anions and universal electrode-active features at high/low potential (cathode/anode side), which have been confirmed by the electrochemical analysis, characterizations and theoretical calculations. Furthermore, aHATN-CTF also shows potential applications in all-organic symmetric batteries (AOBs), flexible AOBs (FAOBs) and other rechargeable alkali metal-ion batteries. Our findings highlight the importance of redox-active polymers with multiple redox-active sites and multiple electrode-active features and open a new avenue to construct organic alkali metal-ion batteries.

Ethynyl and Furyl Functionalized Porphyrin Complexes as New Organic Cathodes Enabling High Power Density and Long-Term Cycling Stability.

Organic cathode materials have recently attracted abundant attention due to their flexible structural tunability and recyclability. However, the low intrinsic electrical conductivity and high solubility in electrolytes of organic electrode materials have significantly limited their practical application. Herein, we present [5,15-bis(ethynyl)-10,20-difurylporphinato] copper(II) (CuDEOP) as a new cathode for rechargeable organic lithium batteries (ROLBs). The combination of both ethynyl and furyl groups of the CuDEOP cathode with a nanorod structure renders it with enhanced structural stability and an extended delocalized π-electron system to deliver excellent cycling stability (capacity retention of 76% after 6000 cycles) and a high power density (16 kW kg-1). The furyl electroactive groups participate in charge storage contribution to achieve a reversible six-electron-transfer redox reaction in a specific voltage range. The mechanism characterizations indicate that the nitrogen atoms on the porphyrin ring act as active sites to alternatively store both PF6- anions and Li+ cations, and the charge storage process is a pseudocapacitive-dominated reaction. This observation will offer a new avenue for designing functionalized molecules for electrochemical energy-storage (EES) systems.

Pyrazine and crown ethers: functional covalent organic polymers for (solar-assisted) high capacity and rate performance lithium-organic battery

Multifunctional two-dimensional (2D) covalent organic polymers (COPs) benefiting from unique features display great potential in lithium-organic batteries yet are rarely reported. In this work, we fabricate a novel conjugated polymer (TQ-COP) functioned with flexible crown ethers and pyrazine redox-active sites, used as an organic rechargeable battery cathode. The Fourier transform infrared spectroscopy (FT-IR) and 13C cross-polarization and magic-angle spinning nuclear magnetic resonance (MAS NMR) verify the chemical identity of redox-active units formed during polymerization. In this structure, pyrazine-redox components exhibit a maximum six-electron transfer per active site, resulting in an initial specific capacity of 162 mA h/g(20 mA/g). Because of macrocyclic cavities and preferential coordination with the alkali metal ions of crown ethers, the rate determining step is changed into a charge transfer process, urging TQ-COP to emerge with a superior rate performance (132 mA h/g at 2 C, 81% vs. 0.1 C). Furthermore, the introduction of crown ethers facilitates photo-excited charge-carriers transfer by narrowing the HOMO-LUMO gap, rendering a photo-assisted lithium-organic battery with significant photovoltage responses and ∼10% improvement of battery round-trip efficiency under illumination, demonstrating its promising capability of solar energy utilization. This work proposes new insights into multifunctional COPs for advanced lithium-organic batteries.

Micro-nano morphology regulation via electrospinning strategy enables high-performance high-voltage polymer cathodes for lithium-organic batteries

Organic/polymer cathodes have attracted increased attention due to their versatile structures, low cost, facile synthesis, and environmental friendliness. However, the high viscosity of polymers makes achieving manipulable morphology in organic/polymer:conductive agent composites a significant challenge. In response, we report herein a new electrospinning strategy for controlling the micro-nano morphologies of a p-type high-voltage polymer, poly(N-vinyl carbazole) (PVK), with carbon black Super P (SP). The PVK-based fiber cathode (PSP50) made through this strategy possesses a fine 3D nanoporous structure, fast ion/electron transport properties, and ultrafast reaction kinetics. In comparison with PSP electrodes made by traditional methods, like dry-mixing (PSP-dm) and coating (PSP-co), PSP50 exhibits a high discharge capacity of 122 mAh g−1 at 50 mA g−1 with an average discharge voltage of 3.75 V, remarkable rate capability of 1 A g−1, and superior cycling stability with 73% capacity retention after 1000 cycles at 500 mA g−1. This study provides a new direction for regulating micro-nano morphologies of organic cathodes for high-performance lithium-organic batteries.

Bio-derived 4-electron-accepting carbonyl-N-methylpyridinium species for high-performance lithium-organic batteries

Structural diversity and low cost make organic materials ideal candidates for next-generation energy storage applications. To obtain high-performance electrode materials for lithium (Li)-organic batteries, the identification of suitable organic molecules that exhibit multiple and stable redox states, limited solubility, and improved conductivity is critical. The leverage of bio-derived redox-active motifs holds great promise due to their built-in functionality and availability from natural resources. Here, we report the structural evolution from naturally occurring, two-electron accepting carbonylpyridinium units into four-electron accepting small organic molecules and their incorporation into high-performance polymers. Impressively, CP2 -based electrode can read up to 807 mAh g −1 after 300 cycles at a current density of 0.2 A g −1 . The superior battery performance rivals that of state-of-the-art Li-ion batteries and opens the door toward significantly broadening the impact of this critical energy-storage technology. • Bio-derived four-electron-accepting carbonyl-pyridinium building blocks are designed • Donor-acceptor structure enhances electronic conductivity and battery performance • Polymerization exhibits improved cycling stability and rate performance Bio-derived redox-active motifs hold great promise in next-generation energy storage applications due to their built-in functionality and availability from natural resources. Here, Wang et al. report the structural evolution from naturally occurring, electron-accepting carbonylpyridinium units into four-electron-accepting small organic molecules and conjugated polymers for high-performance lithium (Li)-organic batteries.

A high‐voltage solid‐state organic lithium battery based on 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane cathode

Organic electrode material has advantages of renewable, low cost, and environmentally friendly, which are promising for application in lithium-ion batteries (LIBs). However, most organic cathode materials demonstrate low redox potentials and are easy to dissolve in conventional liquid electrolytes that retard the development of organic lithium batteries (OLBs). In this paper, 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), a novel organic electrode with a high-voltage of 3.4 V is reported as cathode material for OLBs. To suppress the flow out of active materials and improve cycling performance, solid-state PEO-LLZTO is used as an electrolyte. Through adjusting the molecular weight of PEO, optimizing electrochemical windows, and using electrolyte additive, we finally fabricated an organic solid-state lithium battery which delivered a capacity of 80 mAh g−1 at a current density of 10 mA g−1, and maintained 77% capacity after 50 cycles. Our work provides a new material option for high-voltage OLBs, and gives instructions for fabrication of solid-state OLBs with high-stability.

Conjugated Tetrathiafulvalene Carboxylates for Stable Organic Lithium Batteries

AbstractOrganic electrode materials are potential energy storage materials for the next generation lithium batteries. Herein, carboxylate groups are installed to a conjugated tetrathiafulvalene (TTF) platform to yield two compounds, namely lithium tetrathiafulvalene‐dicarboxylate (TTF‐Li2) and lithium tetrathiafulvalene‐tetracarboxylate (TTF‐Li4), as stable anode materials for lithium batteries. The low solubility in the electrolyte, brought about by the carboxylate groups, and high rechargeability ensured by the conjugated TTF platform lead to excellent battery performance. After cycling at a current density of 0.5 C for 120 cycles, a net specific capacity of 108.19 mAh g−1 and 217.55 mAh g−1 is obtained for the TTF‐Li2 and TTF‐Li4 anodes containing 70 wt.% of active materials, corresponding to 61.4 % and 82.0 % of their theoretical capacities, respectively. The density functional theory (DFT) calculation confirms the well‐delocalized charge for both TTF‐Li2 and TTF‐Li4. Therefore, the TTF‐Li2 and TTF‐Li4 are promising anode materials for lithium batteries.

Porphyrin-based conjugated microporous polymers with dual active sites as anode materials for lithium-organic batteries

Conjugated microporous polymers have been regarded as ideal electrode materials for green lithium-ion batteries (LIBs) considering their advantages such as insolubility, adjustable structure and porosity. Herein, we synthesize porphyrin-based CMPs (Co-PCMPs) with dual active sites composed of metal-N4 conjugated macrocycle and conjugated carbonyl groups through the condensation polymerization. In view of the rational design and unique organic skeleton, when used as the anode material for LIBs, Co-PCMPs show a high capacity (700 mAh g −1 at 0.05 A g −1 ) and excellent rate capability (400 mAh g −1 at 1.0 A g −1 ). Meanwhile, theoretical calculations are used to further study the lithium storage mechanism of Co-PCMPs as the anode material for LIBs. In addition, a full cell is also assembled by using LiCoO 2 as the cathode material and Co-PCMPs as the anode material, which also shows a high capacity (212 mAh g −1 at 0.05 A g −1 ) and good rate capability (116 mAh g −1 at 0.2 A g −1 ), implying the possibility of practical applications of this type of conjugated microporous polymers. We synthesize porphyrin-based conjugated microporous polymers with dual active sites composed of metal-N4 conjugated macrocycle and conjugated carbonyl groups through the condensation polymerization, which could be served as anode materials to a full cell of lithium ion batteries. • Porphyrin-based conjugated microporous polymers were prepared by condensation reaction. • The polymers with dual active sites were used as anode materials for lithium ion batteries. • Full cell is also assembled to show the possibility of practical applications of these polymers.

Cross-Linked PVA/HNT Composite Separator Enables Stable Lithium-Organic Batteries under Elevated Temperature

Li-organic batteries (LOBs) are promising advanced battery systems because of their unique advantages in capacity, cost, and sustainability. However, the shuttling effect of soluble organic redox intermediates and the intrinsic dissolution of small-molecular electrodes have hindered the practical application of these cells, especially under high operating temperatures. Herein, a cross-linked membrane with abundant negative charge for high-temperature LOBs is prepared via electrospinning of poly(vinyl alcohol) containing halloysite nanotubes (HNTs). The translocation of negatively charged organic intermediates can be suppressed by the electronic repulsion and the cross-linked network while the positively charged Li+ are maintained, which is attributed to the intrinsic electronegativity of HNTs and their well-organized and homogeneous distribution in the PVA matrix. A battery using a PVA/HNT composite separator (EPH-10) and an anthraquinone (AQ) cathode exhibits a high initial discharge capacity of 231.6 mAh g-1 and an excellent cycling performance (91.4% capacity retention, 300 cycles) at 25 °C. Even at high temperatures (60 and 80 °C), its capacity retention is more than 89.2 and 80.4% after 100 cycles, respectively. Our approach demonstrates the potential of the EPH-10 composite membrane as a separator for high-temperature LOB applications.

Insoluble Naphthoquinone‐Derived Molecular Cathode for High‐Performance Lithium Organic Battery

AbstractOrganic electrode materials have attracted significant attention for rechargeable lithium organic batteries owing to the anticipated electrochemical property and environmentally friendly features. Benzoquinone and naphthoquinone as the simplest quinone substances have been considered as promising cathode materials because of their high theoretical specific capacities and discharge voltages. However, they are soluble in most organic liquid electrolytes, which results in poor electrochemical performance. Herein, a novel molecular cathode material based on naphthoquinone, i.e., 2,2'‐(1,4‐phenylenedithio) bis(1,4‐naphthoquinone) (1,4‐PNQ), is designed and synthesized. It shows greatly decreased solubility as a result of strong intermolecular interactions. In a lithium half cell, it exhibits high carbonyl utilization of close to 100% with a high initial capacity of 231 mAh g‐1. Meanwhile, 1,4‐PNQ presents improved cyclability, retaining a high capacity of 185 mAh g‐1 after 120 cycles. Remarkably, it retains 93.5% of the initial capacity after 500 cycles at 5 C rate. This work provides a novel molecular design strategy to develop naphthoquinone‐derived cathode materials for high performance lithium organic batteries.

Thiophene functionalized porphyrin complexes as novel bipolar organic cathodes with high energy density and long cycle life

The low intrinsic electrical conductivity, low specific capacity, and high solubility of organic electrode materials have significantly plagued its practical application in electrochemical energy storage systems. Herein, bipolar organic molecules combining porphyrin and thiophene functional groups, [5, 15-bis-(ethynyl)-10, 20-dithienylporphinato]M(II), (M= Cu, Zn, Co, and 2H) are proposed as new cathodes. Thiophene groups and nitrogen atoms act as active sites affording 8 electrons transfer during redox reaction which strongly interact with both cations (Li+) and anions (PF6−), enabling high charge storage capability and fast kinetic. When CuDETP is used in organic lithium batteries, it delivers a reversible capacity of 350 mAh g − 1 at 100 mA g − 1 and a high specific energy density of 773.6 Wh kg−1 (based on the cathode material). Meanwhile, extremely stable cyclability up to 9000 cycles is achieved owing to the self-polymerziation during initial charging process. This investigation has great enlightenment for the molecular design and application of organic electrodes in terms of both high energy densities and long cycling life.

Designing and tuning the components of random terpolymers toward Ampere-hour-scale organic lithium batteries

Terpolymer cathode materials are synthesized by designing and tuning their active components, functional groups and carbon backbones. In an A h-scale organic lithium pouch cell, the terpolymer cathode achieves a good cycling stability and a high energy density.

A fluorinated macrocyclic organodisulfide cathode for lithium organic batteries.

We design and synthesize a fluorinated macrocyclic organodisulfide through a simple one-step oxidation of 2,5-difluorobenzene-1,4-dithiol in dimethyl sulfoxide. It contains a dimer, trimer, and tetramer of 2,5-difluorobenzene-1,4-disulfide, which are insoluble in ether electrolyte. When evaluated in a lithium half-cell, it delivers a discharge specific capacity of 268.6 mA h g-1 at 0.1C. The capacity retention rate is 78.1% after 200 cycles.

A thianthrene-based small molecule as a high-potential cathode for lithium-organic batteries.

Redox-active organic materials have shown great potential as electrodes in lithium-ion batteries (LIBs). However, most of them showed a low discharge potential. We report a thianthrene-based small molecule (BDBDT), which could be facilely synthesized, as a high-potential cathode. The BDBDT cathode exhibited good electrochemical performance with a discharge plateau at 3.9 V (vs. Li/Li+) and a discharge capacity of 63 mA h g-1 after 100 cycles at 500 mA g-1 (∼10C). Our results demonstrate that thianthrene-based molecules are promising for the development of high-potential organic electrodes towards rechargeable batteries with high energy and power density.

Long-life superlithiation of few-layered covalent organic nanosheets via graphene quantum dots/carbon nanotube stabilized three-dimensional architecture

The graphene quantum dots/CNT stabilized few-layered hyper-conjugated covalent organic nanosheet is synthesized and exhibits excellent electrochemical performance for lithium-organic batteries.

Multiredox Tripyridine-Triazine Molecular Cathode for Lithium-Organic Battery

Multiredox Tripyridine-Triazine Molecular Cathode for Lithium-Organic Battery

Low-cost carbonyl polymer design for high-performance lithium-organic battery cathodes

Carbonyl polymers, such as poly(anthraquinonyl sulfide) (PAQS) and poly(benzoquinonyl sulfide) (PBQS), are typically selected as cathode materials for lithium-organic batteries (LOBs) because of their inherent high theoretical capacity and low solubility in the electrolyte. However, their commercialization is hindered by their relatively complex synthesis routes, low yields, and high cost. Herein, a carbonyl polymer poly(piperazine-alt-benzoquinone) (NP2), obtained from the polymerization of vanillin and piperazine with oxidative amination at the theoretical production cost of US $0.48 per gram, exhibits a high reversible capacity of 257 mAh g−1, leading to a cost performance of US $0.19 per 100 mAh, which is superior to the reported carbonyl polymers. Furthermore, ex situ X-ray photoelectron spectroscopy and ex situ and in situ Fourier-transform infrared measurements release the reversible electrochemical reaction mechanism of NP2 based on carbonyl redox chemistry. This study demonstrates a simple and effective strategy to synthesize low-cost carbonyl polymers, which will pave the way for their future application in high-performance LOBs.

Biredox-Ionic Anthraquinone-Coupled Ethylviologen Composite Enables Reversible Multielectron Redox Chemistry for Li-Organic Batteries.

Organic compounds bearing redox‐active ionic pairs as electrode materials for high‐performance rechargeable batteries have gained growing attention owing to the properties of synthetic tunability, high theoretical capacity, and low solubility. Herein, an innovative biredox‐ionic composite, i.e., ethylviologen dianthraquinone‐2‐sulfonate (EV‐AQ2), affording multiple and reversible active sites as a cathode material in lithium‐organic batteries is reported. EV‐AQ2 exhibits a high initial capacity of 199.2 mAh g−1 at 0.1 C rate, which corresponds to the transfer of two electrons from one redox couple EV2+/EV0 and four electrons from two redox‐active AQ− anions. It is notable that EV‐AQ2 shows remarkably improved cyclability compared to the precursors. The capacity retention is 89% and the Coulombic efficiency approaches 100% over 120 cycles at 0.5 C rate. The results offer evidence that AQ− into the EV2+ scaffold with multiple redox sites are promising in developing high‐energy‐density organic rechargeable batteries.