Lithium-ion Battery Cathode Research Articles

How dispersed LLZTO enhances ionic conductivity in LiFePO4 composite cathodes for solid-state batteries

To improve the ionic conductivity of the LiFePO4 cathode for high-performance solid-state lithium-ion batteries, we incorporated the chemically stable and ion-conductive Li6.75La3Zr1.75Ta0.25O12 (LLZTO) into the cathode. We discovered that the impact of this incorporation on enhancing conductivity was influenced by how well the LLZTO particles were dispersed. A solid-state battery constructed with the LiFePO4 cathode without any LLZTO incorporated exhibited an initial capacity of 146 mAh g−1 at 0.2C, with a retention of 26 % after 100 cycles of charge-discharge. When the cathode was incorporated with LLZTO particles in their original agglomerated state, the initial capacity remained similar to the pristine one, but the retention decreased to <20 %. However, when LLZTO was well-dispersed during incorporation, the initial capacity increased to 160 mAh g−1, and retention improved to over 95 %. The difference in the effectiveness of incorporating dispersed and agglomerated LLZTO on the electrochemical performance has been clarified to be mainly related to the polarization of Li+ during transport in the cathodes. This was elucidated by numerical simulations based on finite element analysis, which revealed that incorporating LLZTO agglomerates leads to a deficiency of Li+ transport in specific regions within the LiFePO4 cathode and non-uniform Li+ transport through LLZTO, resulting in reduced overall cathode conductivity and battery performance.

Digital Twin Reveals the Impact of Carbon Binder Domain Distribution on Performance of Lithium‐Ion Battery Cathodes

The rising demand for high‐performance lithium‐ion batteries (LIBs) emphasizes the need for precise electrode design. The carbon binder domain (CBD) within electrodes, crucial for electron transport and structural integrity, can impede lithium‐ion transport and reduce electrochemically active sites. This study leverages digital twin technology to investigate the impact of CBD distribution along the electrode thickness on LIB cathode performance. Virtual LIB cathodes with varying CBD configurations are generated, and their performance using 3D heterogeneous electrochemical modeling is evaluated. The results reveal that a steep CBD gradient significantly diminishes charge capacity compared to a mild gradient, particularly at higher current rates. This reduction is attributed to an increased tortuosity factor and an uneven distribution of electrochemical activity, which adversely affect mass transport and electrochemical reaction dynamics. These effects are more pronounced at lower porosities and higher loading levels. These findings highlight that optimizing CBD distribution is critical for advancing electrode design and enhancing LIB cathode performance.

Fully sp2 Carbon-Conjugated Covalent Organic Frameworks with Multiple Active Sites for Advanced Lithium-Ion Battery Cathodes.

Covalent organic frameworks (COFs) hold great promise for rechargeable batteries. However, the synthesis of COFs with abundant active sites, excellent stability, and increased conductivity remains a challenge. Here, chemically stable fully sp2 carbon-conjugated COFs (sp2c-COFs) with multiple active sites are designed by the polymerization of benzo[1,2-b:3,4-b':5,6-b'']trithiophene-2,5,8-tricarbaldehyde) (BTT) and s-indacene-1,3,5,7(2H,6H)-tetrone (ICTO) (denoted as BTT-ICTO). The morphology and structure of the COF are precisely regulated from "butterfly-shaped" to "cable-like" through an in situ controllable growth strategy, significantly promoting the exposure and utilization of active sites. When the unique "cable-like" BTT-ICTO@CNT is employed as lithium-ion batteries (LIBs) cathode, it exhibits exceptional capacity (396 mAh g-1 at 0.1 A g-1 with 97.9 % active sites utilization rate), superb rate capacity (227 mAh g-1 at 5.0 A g-1), and excellent cycling performance (184 mAh g-1 over 8000 cycles at 2.0 A g-1 with 0.00365 % decay rate per cycle). The lithium storage mechanism of BTT-ICTO is exhaustively revealed by in situ Fourier transform infrared, in situ Raman, and density functional theory calculations. This work provides in-depth insights into fully sp2c-COFs with multiple active sites for high-performance LIBs.

Accelerating Li-Ion Diffusion in LiFePO4 by Polyanion Lattice Engineering.

Despite the widespread commercialization of LiFePO4 as cathodes in lithium-ion batteries, the rigid 1D Li-ion diffusion channel along the [010] direction strongly limits its fast charge and discharge performance. Herein, lattice engineering is developed by the planar triangle BO3 3- substitution on tetrahedron PO4 3- to induce flexibility in the Li-ion diffusion channels, which are broadened simultaneously. The planar structure of BO3 3- may further provide additional paths between the channels. With these synergetic contributions, LiFe(PO4)0.98(BO3)0.02 shows the best performance, which delivers the high-rate capacity (66.8 mAhg-1 at 50 C) and long cycle stability (ultra-low capacity loss of 0.003% every cycle at 10 C) at 25°C. Furthermore, excellent rate performance (34.0 mAhg-1 at 40 C) and capacity retention (no capacity loss after 2500 cycles at 10 C) at -20°C are realized.

Mechanical failure modeling for cathode sheets

The mechanical integrity of the cathode is critical for the operation and safety of lithium-ion batteries (LIBs). This study presents a comprehensive exploration of the progression and underlying mechanisms of failure within LIB cathodes, employing a combination of experimental and numerical methodologies. First, shear and 180° peel tests are designed and conducted to calibrate the parameter values governing the interface between the aluminium (Al) foil and the active layer, leveraging cohesive zone modeling (CZM). Furthermore, based on finite element modeling (FEM) and extended finite element modeling (XFEM), failure criteria and damage models are introduced to simulate the damage behavior of both Al foils and active layer. Notably, XFEM computes the initiation and expansion of the crack in cathode. The numerical simulation demonstrates a good correlation with the experimental observations, effectively delineating the failure process of the cathode. Moreover, a parametric analysis is conducted to study the influence of the active layer and interface on cathode failure. It reveals that as the failure strain of the active layer increases, the failure strain of the cathode rises, ultimately converging with the failure strain of an isolated Al foil. However, the failure strain of cathode decreases and then increases with increasing interface peel strength. At a peel strength of 304 N/m, the stress distribution within the active layer and the interface is more uniform compared to the lower peel strength scenarios. Besides, the interface stress transfer behavior leads to the failure of the Al foil in early. The results enhance our understanding of the failure process and mechanisms in LIB electrodes and thus provide guidance for the design and fabrication of cathode.

Enhanced cyclability and energy density of mid-nickel layered oxide cathode material LiNi0.55Mn0.25Co0.20O2 by niobium doping via solvothermal method

Ni-based layered oxide materials are among the most promising cathode materials for the next generation of lithium-ion batteries due to their higher energy capacity. However, capacity decay occurs due to degradation mechanisms that reduce the electrochemical performance of this type of material. This work aims to synthesize Nb-doped LiNi0.55Mn0.25Co0.20O2 (Nb-NCM) materials via the solvothermal method to enhance the cyclability and energy density of the layered oxide cathode. The effects of Nb doping on the microstructure and the electrochemical performance of the cathodes are investigated. The introduction of the contents of Nb expands the structural lattice parameters and decreases the Li+/Ni2+ cation mixing degree of the NCM cathode. Furthermore, the Nb doping enhances the electrochemical activity of LiNi0.55Mn0.25Co0.20O2, increasing its initial discharge capacity to 169.61 mAhg−1 when 1% of Nb was used as a dopant (1%Nb-NCM) in contrast to the capacity of 149.45 mAhg−1 presented by the pristine material. The modified 1.0%Nb-NCM material also exhibits remarkable cycling performance with a capacity retention of 92.7% after 100 cycles at the rate of 1 C (2.8–4.3 V). This work suggests a rational strategy for high-performance cathode for lithium-ion batteries, proposing the extension of Nb doping to enhance Ni-mid material's cyclability.

Tuning architectural synergy reactivity of nano-tin oxide on high storage reversible capacity retention of ammonium vanadate nanobelt array cathode for lithium-ion battery

Enabling ambient cycling stability of vanadium-based materials is of fundamental importance in the advancement of next generation electrodes for high-performance lithium-ion batteries. Although, extending these host layered nano-architectures illustrate the effective electrochemical activity by regulating the gallery space for fast Li+ storage, the reported structural integrity in terms of the cycling stability for vanadium-based cathodes is highly challenging. In present study, a series of NH4V4O10-SnO2 (NHV-SnO2) nanocomposite consisting of diverse contents of SnO2 (x: 5.0, 15.0 and 30.0 wt%) were synthesized through a three-step program based on sonochemical-calcination-hydrothermal treatment and employed as an advanced energetic material for lithium-ion battery cathodes. For the first time, understanding the impact of SnO2 loading on electrochemical reactions of NHV-based electrodes was regarded as an effective engineering strategy to optimize structural modulation and cell lifetime without distinct capacity fading. Notably, combination of NHV and SnO2 in optimum proportions not only enhances the specific surface area, but also expand buffer the volume change for lithium-ion intercalation/extraction. By this design, the assembled battery containing 15.0 wt% SnO2 illustrated stable capacities of 301.77 mAh g−1 (30 mA g−1) and 232.05 mAh g−1 (240 mA g−1) with capacity retention values as high as 97.94 % and 97.03 % for 50 cycles, respectively. Of note, the results described here could show a vital guidance toward designing better composite-based cathode material for energy storage devices.

In-depth approach and establishment from a structural perspective of LiFePO4 cathodes for lithium-ion batteries by a two-step sintering

Most synthesis of olivine LiFePO4 (LFP) studies have emphasized the importance of a two-step sintering process for the formation of a uniform carbon coating. However, in this study, it is found that, as an advantage of the two-step sintering process, stable carbonization not only improves lithium-ion conductivity by forming a coating layer but also increases the uniformity of the internal crystal structure. In addition to basic crystallinity and structure analysis using X-ray diffraction (XRD), in-depth calculations are performed to explain the formation mechanism of crystal structure according to the two-step sintering process and the temperature of the first sintering step. In particular, lattice defects and structural uniformity are closely investigated from the crystal structure perspective by comparing lattice micro-strain and dislocation density. Improvement in lithium-ion conductivity from structural uniformity is also demonstrated through cyclic voltammetry (CV) analysis. As a result, it is confirmed that LFP, which undergoes a high-temperature two-step sintering, has high capacity and excellent cycle retention at high rates. Furthermore, ex-situ XRD analysis demonstrates the performance difference according to lithium-ion mobility by comparing the LiFePO4/FePO4 two-phase transformation reaction of two-step sintered LFP and the plateau stability during charging.

Study on Cycle Performance and Rate Performance of Lithium Cobalt Oxide

Lithium cobalt oxide (LiCoO2 ) cathode material, with its high energy density and operating voltage, is currently a mainstream material for lithium-ion battery cathodes. &amp;nbsp;&amp;nbsp;However, &amp;nbsp;the &amp;nbsp;crystal &amp;nbsp;structure &amp;nbsp;collapse &amp;nbsp;and &amp;nbsp;lattice &amp;nbsp;oxygen &amp;nbsp;evolution under high-voltage conditions lead to rapid capacity decay, severely limiting its practical applications. &amp;nbsp;&amp;nbsp;This paper &amp;nbsp;analyzes the main factors affecting the cycle performance and rate performance of lithium cobalt oxide, considering the physic- ochemical properties of the particles, including elemental content and particle size, and provides a mathematical model linking these properties to electrochemical per- formance. &amp;nbsp;The study offers insights for the practical production of high-voltage lithium cobalt oxide materials. At the beginning, we embarked on investigating the correlation between the physicochemical attributes (encompassing elemental composition and particle size) of lithium cobalt oxide and its cycle performance. An Ordinary Least Squares (OLS) linear regression model was formulated, yielding a robust fit with an R-Squared value of 0.94. This model was subsequently optimized through the application of an XGBoost algorithm, achieving an R-Squared value nearing unity, signifying a remarkable enhancement in model accuracy. Visual analysis of the results pinpointed the primary determinants of cycle performance, arranged in descending order of significance: 'Cycle Index,' Mg content, particle size distribution (D10), Zn, and Al. Then, our attention shifted to examining the link between the aforementioned physicochemical characteristics and the rate performance of lithium cobalt oxide. The Jarque-Bera and Shapiro-Wilk tests confirmed the normality of the data, fulfilling the prerequisites for hypothesis testing. An OLS linear regression model was developed, demonstrating a strong goodness-of-fit with an R-Squared value exceeding 0.8. This model was further honed with an XGBoost model, which achieved an R-Squared score approaching 1, indicating a substantial refinement in model precision. The visualization of model outcomes illuminated the key factors influencing rate performance, ranked in descending order of importance: particle size distribution (D50), Al, Mn, Zn, Mg, Ni, and Fe. Lastly, we devised an optimal strategy that encompasses the incorporation of strategic doping elements, the utilization of high-temperature sol-gel methods to bolster cycle performance, and coating modifications aimed at enhancing rate performance. This holistic approach fosters the structural stability of lithium cobalt oxide crystals, fortifying their high-potential cycle capabilities, and concurrently elevating their rate performance.

The Effect of Mono-Halogenation on the Performance of Anthraquinone Cathode in Lithium-Ion Batteries

To investigate the effect of mono-halogenation on the performance of anthraquinone cathode in lithium-ion batteries, the structures and electrochemical properties of AQ derivatives functionalized with single chlorine and bromine were studied. The microstructure and morphology were characterized by XRD and SEM, and the electrochemical properties were conducted using galvanostatic charge/discharge, cyclic voltammetry and electrochemical impedance spectroscopy. 1-BrAQ, 2-BrAQ, and 2-ClAQ showed improved cyclic stability and higher platform voltage than the AQ cathode, and the capacity retention rates of 2-ClAQ and 2-BrAQ after 50 discharge cycles are 64.6% and 77.8%, respectively, which are twice the capacity retention rate of the AQ positive electrode under the same conditions.

Ambient-temperature aqueous electrochemical route for direct Re-functionalization of spent LFP cathodes of lithium-ion batteries

Relithiation is a critical step in the direct recycling process, which is the most promising method for spent LiFeIIPO4 (LFP) batteries recycling. It involves the reduction of FeIIIPO4 (FP) in a Li-ion-rich environment and is generally performed by high-temperature sintering or hydrothermal methods. This study proposes an ambient temperature electrochemical relithiation method in an aqueous solution. It follows a preliminary delithiation step described in our previous publications. The results confirmed that FP can be efficiently relithiated in either Li2SO4 or LiHCO3 electrolyte. The reaction follows mostly a Cottrellian behavior, determined from potentiostatic experiments, indicating that diffusion in solution is a critical mechanism. Application of this electrochemical relithiation process to FP originating from spent LFP resulted in a 96 % relithiation yield at a current efficiency of 91 %. The overall recycling process successfully re-functionalized deeply damaged spent LFP by recovering up to 99 % of the LFP's original discharge capacity, achieving up to 153 mAh g−1 at C/12. Meanwhile, the initial discharge capacity of the re-functionalized LFP at 1C attained 119 mAh g−1, which interestingly increased upon cycling, reaching 131 mAh g−1 after 225 cycles. This increase could be associated with electrochemical activation promoted by cycling-induced LFP crystal annealing and/or by electrochemical milling.

Synthesis and Electrochemical Performance Enhancement of Li2MnSiO4 Cathode Material for Lithium‐Ion Batteries via Mn‐Site Ni Doping

AbstractIn exploring the potential of Li2MnSiO4 as a cathode material for lithium‐ion batteries (LIBs), the key challenges often involve enhancing electronic conductivity and lithium‐ion diffusion rates. To address these issues, this paper proposes the combination of solid‐state doping and a two‐step calcination process to successfully prepare the Li2Mn1−xNixSiO4 series of cathode materials, where Ni substitutes Mn at different doping amounts (x = 0, 0.02, 0.04, 0.06, 0.08). The use of chemically equivalent Ni2+ ions to replace Mn2+ ions is an effective method. Since the ionic radius of Ni2+ is smaller than that of Mn2+, this substitution can create more voids in the lattice structure. These increased voids provide smoother channels for the transport of electrons and lithium ions, thereby improving the material's electrical conductivity. At a Ni doping amount of 0.06, the material exhibits optimal electrochemical performance, achieving a discharge capacity of 155 mAh g−1 at 0.1 C, significantly superior to undoped lithium manganese silicate. The doping of Mn sites with Ni significantly improves the conductivity and lithium‐ion diffusion capabilities of Li2MnSiO4, revealing the tremendous potential of doping strategies in optimizing the performance of LIBs cathode materials.

Nickel‐Manganese‐Based Layered Oxide for Sodium Ion Battery Cathode Materials

Sodium‐ion batteries (SIBs) have demonstrated significant potential as alternatives to conventional lithium‐ion batteries (LIBs) for modern grid and mobile energy storage applications, due to the abundant natural resources and low cost of sodium. Layered transition metal oxides (LTMOs) have attracted focused research attentions due to their high specific capacities, energy densities as well as the compatible preparation processes with those of LIBs cathode materials. Among these, Ni/Mn‐based LTMOs (NMLOs) are particularly noteworthy for their cost‐effectiveness and superior electrochemical performance, such as excellent capacity retention, voltage stability, high operating voltage and rate capability. In this review, we briefly introduce the synthesis methods of NMLOs, discuss the challenges, and summarize the solutions. The insights presented may contribute to the development of NMLOs based SIBs.

Naphthalene Diimide-Based Cyanovinylene-Containing Conjugated Organic Polymers for Efficient Lithium-Ion Battery Electrodes.

The pursuit of innovative organic materials and the examination of the "structure-function" correlation in lithium-ion batteries (LIBs) are crucial and highly desirable. Current research focuses on the creation of novel conjugated organic polymers with polycarbonyl groups and examining the impact of electrode structure on the function of lithium-ion batteries. In this paper, two novel cyanovinylene-based conjugated organic polymers, NBA-TFB and NBA-TFPB, are synthesized using a Knoevenagel condensation reaction with naphthalene diimide as the integral unit. The performance of NBA-TFB and NBA-TFPB as cathodes in lithium-ion batteries is investigated. Improved conductivity and increased active site density in NBA-TFPB resulted in superior electrochemistry compared to NBA-TFB. Specifically, NBA-TFPB exhibited a larger reversible capacity (87.58 mAh g-1 at 0.2C and 88.34% retention after 100 cycles), exceptional rate capability (66.13 mAh g-1 at 5C), and robust cycling stability (99.58% coulombic efficiency at 1C and 60.71% retention after 2000 cycles). This study expands the family of diimide-based naphthalene polymers and provides a strategy for enhancing the performance of organic electrode materials containing polycarbonyl structure.

Insulating behaviour in room temperature rhombohedral LiNiO2 cathodes is driven by dynamic correlation

Abstract Inspired by the experimental finding of a paramagnetic insulating state in rhombohedral LiNiO2, a lithium-ion battery cathode of great interest, we calculate the electronic, magnetic, and optical properties of LiNiO2 employing a range of single-particle and many-body methods. Within density-functional theory (DFT) using the generalized-gradient approximation (GGA), meta-GGA, and hybrid functionals, we obtain a ferromagnetic half-metallic ground state for rhombohedral LiNiO2, as has been seen previously. Self-consistent GW calculations including self-interaction corrections beyond DFT for various flavours show an electronic band gap albeit with a small quasiparticle peak at the Fermi energy. Moving beyond this, room temperature state-of-the-art dynamical mean-field theory (DMFT) calculations on rhombohedral LiNiO2 show for the first time a gap of combined Mott and charge-transfer character. The paramagnetic insulating state has a band gap of ~0.6 eV, in excellent agreement with experiments and is in sharp contrast to DFT calculations that require the presence of an extra structural symmetry breaking in the form of Jahn–Teller distortions to open a gap. We observe Ni to be in a +2 state in a d 8L configuration, with a charge-transfer ligand hole in O p, and identify the ligand hole state from the DMFT DOS. We further show that whereas DFT shows the presence of an unphysical metallic Drude peak in the optical absorption spectra, DMFT calculations capture the correct form of the optical absorption spectra, and have an excellent match with the calculated band gap as well. Our results clarify that at room temperature, it is the charge transfer gap with a Mott character that causes rhombohedral LiNiO2’s insulating nature; a structural distortion is not required.

Carbon-decorated hydrated V10O24 nanorods for high-performance lithium-ion battery cathodes

This study reports the successful synthesis of carbon-decorated hydrated V10O24 (HVO@C) nanorods using a facile hydrothermal method. The synthesized material was comprehensively characterized using XRD, FTIR, Raman, TGA/DSC, BET, SEM, and HRTEM to reveal its structure and morphology, and the resulting electrode's electrochemical performance as a lithium-ion battery (LIB) cathode was evaluated for the first time. The HVO@C nanorods exhibited a remarkable initial capacity of 292.5 mAh g−1 at 75 mA g−1 current rate, exceeding most of the reported V2O5-based LIB cathodes. Notably, the HVO@C electrode retained a good capacity retention of 67.1 % and a slower capacity loss rate of 0.26 % after 125 cycles compared to most V2O5-based counterparts with shorter lifespans. This outstanding performance could be due to a synergistic interplay of structural characteristics. The large interlayer spacing within the nanorods facilitated unimpeded Li-ion diffusion, while the short diffusion path minimized transport limitations. Furthermore, the strategic incorporation of carbon coating enhanced electrical conductivity and structural stability, leading to enduring LIB battery performance. These results indicate that in-situ carbon-decorated hydrated V10O24 nanoparticles have great potential as a promising cathode electrode for LIBs with exceptional performance.

Revealing Gliding-Induced Structural Distortion in High-Nickel Layered Oxide Cathodes for Lithium-Ion Batteries.

After charging to a high state-of-charge (SoC), layered oxide cathodes exhibit high capacities but suffer from gliding-induced structural distortions caused by deep Li depletion within alkali metal (AM) layers, especially for high-nickel candidates. In this study, we identify the essential structure of the detrimental H3 phase formed at high SoC to be an intergrowth structure characterized by random sequences of the O3 and O1 slabs, where the O3 slabs represent Li-rich layers and the O1 slabs denote Li-depleted (or empty) layers that glide from the O3 slabs. Moreover, we adopt two doping strategies targeting different doping sites to eliminate the formation of Li-vacant O1 slabs. First, we introduce direct transition metal (TM) pillars between TMO2 slabs achieved through dopants (e.g., Nb) positioned within AM layers, significantly improving the cycling stability. Second, we introduce indirect Li pillars achieved through dopants located at TM layers to adjust the Li-O bond strength. While this strategy can regulate the uniformity of Li at the slab level, it results in an uneven Li distribution at the particle scale, ultimately failing to enhance the electrochemical performance. Our established research strategy facilitates the realization of diverse pillars between TMO2 slabs through doping, thereby offering guidance for stabilizing high-capacity layered oxide cathodes at high SoC.

Realizing the single-crystalline LiNi0.90Mn0.05Co0.05O2 cathode with long-life and high-safety property driven by polysiloxane covering and PO43− doping

As a promising cathode for lithium-ion batteries, the ultra-high nickel content layered oxide LiNi0.90Co0.05Mn0.05O2 demonstrates the great attention for the high discharging capacity. However, the serious capacity attenuation resulted from the instable interface, crystal structure degeneration and strong side-reactions on cathode-electrolyte interphase with charging-discharging drastically restricts its extensive application. To alleviate the intrinsic drawbacks, the combination improvement strategy for polysiloxane covering and PO43− doping is adopted to lower the surface residual alkali amounts, defend the HF/F− attacking and enhance the cation location order of LiNi0.90Co0.05Mn0.05O2. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) are used to evaluate the synthesized samples. The cathodes after the polysiloxane covering and PO43− doping deliver the improved crystal structure, larger lattice parameters and superior electrochemical properties. The polysiloxane coated and PO43− doped sample exhibits a high discharging capacity of 147.5 mAh g−1 at 10.0C rate and 155.4 mAh g−1 at −30 °C, remains a capacity of 193.2 mAh g−1 at 1.0C after 300 cycles with a retention of 91.2 %. Besides, when applied in pouch full batteries, it could pass the rigorous safety tests of Bar impact, Overcharging test and Nail penetration successfully, and still maintain the superior cycling stability in practice application.

Electrophoresis study on carbon cloth loaded with LiFePO4 for integrated flexible cathodes in lithium-ion batteries

Electrophoresis study on carbon cloth loaded with LiFePO4 for integrated flexible cathodes in lithium-ion batteries

Free-Standing Poly(vinyl benzoquinone)/Reduced Graphene Oxide Composite Films as a Cathode for Lithium-Ion Batteries.

Quinones with a rapid reduction-oxidation rate are promising high-capacity cathodes for lithium-ion batteries. However, the high solubility of quinone molecules in polar organic electrolytes results in low cycle stability, while their low electric conductivity causes low utilization of electrode materials. In this article, a new p-benzoquinone derivative, poly(vinyl benzoquinone) (PVBQ), is designed and synthesized, and a solution-based method of preparing free-standing PVBQ/reduced graphene oxide (RGO) composite films is developed. PVBQ has a high theoretical specific capacity (400 mA h g-1) because of its low dead moiety mass. In the produced composite films, PVBQ nanoparticles are uniformly dispersed on RGO sheets, which endows the composite films with high electric conductivity and inhibits the dissolution of PVBQ through strong adsorption. As a result, the composite films show a high active material utilization, high practical specific capacity, and excellent cycling stability. PVBQ in the composite membrane containing 60.2 wt % RGO deliver 244 mA h g-1 capacity after 200 charge-discharge cycles at a current density of 300 mA g-1. At a current density of 1500 mA g-1, the reversible specific capacity is still 170 mA h g-1. This work provides a high-performance cathode material for lithium-ion batteries, and the molecular structure and electrode structure design ideas are also instructive for developing other organic electrode materials.