Initial Capacity Research Articles

Stabilizing Ni-rich Single-crystalline LiNi0.83 Co0.07 Mn0.10 O2 Cathodes using Ce/Gd Co-doped High-entropy Composite Surfaces.

Ni-rich layered oxides are promising lithium-ion batteries (LIBs) cathode materials for their high reversible capacity, but they suffer from fast structural degradation during cycling. Here, we report the Ce/Gd incorporated single-crystalline LiNi0.83 Co0.07 Mn0.10 O2 (SC-NCM) cathode materials with significantly enhanced cycling stability. The Gd ions are adequately incorporated in SC-NCM while Ce ions are prone to aggregate in the outer surface, resulting in the formation of a high-entropy zone in the near-surface of SC-NCM, including a Gd doped LiCeO2 (LCGO) shell and Ce/Gd dopant-concentrated layer. The high-entropy zone can effectively inhibit the oxygen evolution and prevent the formation of oxygen vacancies. Meanwhile, it leads to a greatly improved H2-H3 phase transformation reversibility and mitigated stress/strain caused by Li-ion extraction/insertion during (de)lithiation process. The synergetic effects of reduced oxygen vacancies concentration and mitigated stress/strain can effectively prevent the in-plane migration of TM ions, lattice planar gliding as well as the formation of intragranular nanocracks. Consequently, Ce/Gd incorporated SC-NCM (SC-NCM@CG2) delivers a high initial discharge specific capacity of 219.7 mAh g-1 at 0.1 C and an excellent cycling stability with a capacity retention of 90.2 % after 100 cycles at 1.0 C.

Stabilizing Ni‐rich Single‐crystalline LiNi0.83Co0.07Mn0.10O2 Cathodes using Ce/Gd Co‐doped High‐entropy Composite Surfaces

AbstractNi‐rich layered oxides are promising lithium‐ion batteries (LIBs) cathode materials for their high reversible capacity, but they suffer from fast structural degradation during cycling. Here, we report the Ce/Gd incorporated single‐crystalline LiNi0.83Co0.07Mn0.10O2 (SC‐NCM) cathode materials with significantly enhanced cycling stability. The Gd ions are adequately incorporated in SC‐NCM while Ce ions are prone to aggregate in the outer surface, resulting in the formation of a high‐entropy zone in the near‐surface of SC‐NCM, including a Gd doped LiCeO2 (LCGO) shell and Ce/Gd dopant‐concentrated layer. The high‐entropy zone can effectively inhibit the oxygen evolution and prevent the formation of oxygen vacancies. Meanwhile, it leads to a greatly improved H2‐H3 phase transformation reversibility and mitigated stress/strain caused by Li‐ion extraction/insertion during (de)lithiation process. The synergetic effects of reduced oxygen vacancies concentration and mitigated stress/strain can effectively prevent the in‐plane migration of TM ions, lattice planar gliding as well as the formation of intragranular nanocracks. Consequently, Ce/Gd incorporated SC‐NCM (SC‐NCM@CG2) delivers a high initial discharge specific capacity of 219.7 mAh g−1 at 0.1 C and an excellent cycling stability with a capacity retention of 90.2 % after 100 cycles at 1.0 C.

A quantitative analysis method of complex sulfide components for understanding initial capacity degradation mechanism in lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are a strong contender for the new-generation battery system to meet the growing energy demand due to their significantly high energy density (2600 Wh/kg) and cost-effectiveness. However, the practical operating conditions yield an initial capacity of less than 80 % of the theoretical capacity, resulting in a limited lifespan and hindering broader application. What's worse, current mechanism, especially the evolution process of sulfides for the initial capacity degradation is not clear due to the practical difficulties of effective separation and detection of sulfur-containing components. Herein, we have developed an instrumental analysis method enabling graded leaching and quantitative determination of sulfur-containing components. This technology achieves a detection precision surpassing 99.11 %, addressing the inherent deficiency in calculating sulfur-containing components using the decrement method. Applying this method reveals that the presence of lithium polysulfides in the electrolyte (26.34 wt%) after discharging is the primary factor causing insufficient capacity utilization in Li-S batteries. This work not only demonstrates the unique behavior of Li-S batteries at high sulfur loading but also provides a systematic evaluation method to guide further research on high-energy-density batteries, and provides theoretical and technical support to promote the development of high-energy, long-life Li-S batteries.

Stable 2,5‐Dihydroxy‐1,4‐benzoquinone Based Organic Cathode Enabled by Coordination Polymer Formation and Binder Optimization

AbstractOrganic electrode materials are gaining increased attention in energy storage applications, but often encounter challenges such as low capacity and poor cycling stability. This paper explores the utilization of a 1‐D coordination polymer, copper(II)‐2,5‐dihydroxy‐1,4‐benzoquinone (Cu‐DHBQ), as a cathode material for Li‐ion batteries for the first time. Cu‐DHBQ is air‐stable, devoid of coordinated water molecules, and possesses a high theoretical capacity of 266 mAh g−1. With an optimal sodium alginate (SA) binder content of 25 wt%, the Cu‐DHBQ cathode demonstrates a notable initial capacity of 214 mAh g−1 and outstanding cycling stability, retaining 210 mAh g−1 (98% capacity retention) after 200 cycles at a current rate of 100 mA g−1. A comprehensive investigation into the capacity fading mechanisms, the bonding capability of the SA binder, and the interactions between Cu‐DHBQ and SA is conducted using scanning electron microscope (SEM), peel tests, and Fourier transform infrared spectroscopy (FTIR), respectively. Additionally, the electrochemical reaction mechanisms of Cu‐DHBQ are examined using ex situ X‐ray photoelectron spectroscopy (XPS) and FTIR. These findings offer valuable insights into understanding the electrochemical properties of coordination polymers and metal‐organic frameworks based on DHBQ, shedding light on their potential as materials for battery electrodes.

Aromatic Ketones as Mild Presodiating Reagents toward Cathodes for High-Performance Sodium-Ion Batteries.

Chemical presodiation (CP) is an effective strategy to enhance energy density of sodium ion batteries. However, the sodiation reagents reported so far are basically polycyclic aromatic hydrocarbons (PAHs) wth low reductive potential (~0.1 V vs. Na+ /Na), which could easily cause over-sodiation and structural deterioration of the presodiated cathodes. In this work, Aromatic ketones (AKs) are rationally designed as mild presodiating reagents by introducing a carbonyl group (C=O) into PAHs to balance the conjugated and inductive effect. As the representatives, two compounds 9-Fluorenoneb (9-FN) and Benzophenone (BP) manifest favorable equilibrium potential of 1.55 V and 1.07 V (vs. Na+ /Na), respectively. Note that 9-FN demonstrates versatile presodiating capability toward multiple Na uptake hosts (tunneled Na0.44 MnO2 , layered Na0.67 Ni0.33 Mn0.67 O2 , polyanionic Na4 Fe2.91 (PO4 )2 P2 O7 , Na3 V2 (PO4 )3 and Na3 V2 (PO4 )2 F3 ), enabling greatly improved initial charging capacity of the cathode to balance the irrevisible capacity of the anode. Our results indicate that the Aromatic ketones are competitive presodiating cathodic reagents for high-performance sodium-ion batteries, and will inspire more studies and application attempts in the future.

Design and Synthesis of Viologen-based Copolymers for High Performance Li-Dual-Ion Batteries.

Dual-ion batteries based on organic electrodes show great potential to break through the bottlenecks existed in conventional LIBs due to their high specific capacity, lifted working voltage, and environmental benignity. Herein, two innovative viologen-based bipolar copolymers poly(viologen-pyrene-4,5,9,10-tetrone dichloride) (PVPTOCl2 ) and poly(viologen-anthraquinone dichloride) (PVAQCl2 ) were synthesized and applied as high performance cathodes for lithium-dual-ion battery. Bearing the dual-ion storage capability of viologen and carbonyls, as well as the conjugated structure of pyrene-4,5,9,10-tetrone, the synthesized copolymers show remarkable electrochemical performances for LIBs. Compared to PVAQCl2 , PVPTOCl2 shows superior electrochemical performance with high initial specific capacity (235.0 mAh g-1 at 200 mA g-1 ), high reversibility (coulombic efficiency up to 99.96 % at 1 A g-1 ), excellent rate performance (150.3 mAh g-1 at 5 A g-1 ) and outstanding cycling stability (a reversible capacity of 197.5 mAh g-1 at a current density of 1 A g-1 and a low capacity loss per cycle of 0.11‰ during 3000 cycles). Moreover, the charge storage mechanism was systematically investigated by ex-situ FT-IR, ex-situ XPS and DFT calculations. The results clearly reveal the structure-property relationship of the bipolar-molecules, providing a new platform to develop efficient bipolar materials for dual-ion batteries.

Aromatic Ketones as Mild Presodiating Reagents toward Cathodes for High‐Performance Sodium‐Ion Batteries

AbstractChemical presodiation (CP) is an effective strategy to enhance energy density of sodium ion batteries. However, the sodiation reagents reported so far are basically polycyclic aromatic hydrocarbons (PAHs) wth low reductive potential (~0.1 V vs. Na+/Na), which could easily cause over‐sodiation and structural deterioration of the presodiated cathodes. In this work, Aromatic ketones (AKs) are rationally designed as mild presodiating reagents by introducing a carbonyl group (C=O) into PAHs to balance the conjugated and inductive effect. As the representatives, two compounds 9‐Fluorenoneb (9‐FN) and Benzophenone (BP) manifest favorable equilibrium potential of 1.55 V and 1.07 V (vs. Na+/Na), respectively. Note that 9‐FN demonstrates versatile presodiating capability toward multiple Na uptake hosts (tunneled Na0.44MnO2, layered Na0.67Ni0.33Mn0.67O2, polyanionic Na4Fe2.91(PO4)2P2O7, Na3V2(PO4)3 and Na3V2(PO4)2F3), enabling greatly improved initial charging capacity of the cathode to balance the irrevisible capacity of the anode. Our results indicate that the Aromatic ketones are competitive presodiating cathodic reagents for high‐performance sodium‐ion batteries, and will inspire more studies and application attempts in the future.

Sulfide-based MOF material modification of separators: enhancing performance of lithium-sulfur batteries by suppressing shuttle effect

ABSTRACT Lithium-sulfur batteries (LSBs) are extensively studied owing to their high theoretical capacity and low cost. However, the shuttle effect of lithium-sulfur batteries hinders their development. In this study, we obtained a modified separator to inhibit the shuttle effect through physical and chemical adsorption. The CoS2 nanosheets (CSNS) derived from a cobalt-based metal-organic framework (Co-MOF) were synthesized by a simple two-step method involving hydrothermal sulfurization and thermal decomposition. The material was then coated onto a Polypropylene (PP) separator using vacuum filtration and assembled into a LSB for systematic testing and research of its electrochemical performance and mechanism. Thanks to the intrinsic polarity of the CSNs and more active sites brought by the Co-MOF material, the modified separator has strong chemical adsorption and catalytic effects on polysulfides, anchoring and accelerating their conversion. When using the CSNs-PP separator, the LSB achieved a high initial capacity of 1002.4 mAh g−1 at 1 C, with only a 0.099% decay per cycle after 500 cycles. The modified separator effectively alleviating the shuttle effect, reducing internal resistance, weakening reaction polarization, and improving the specific capacity, stability, and reversibility of the battery.

In situ Electrolyte Design: Understanding the Prospects and Limitations of a High Capacity Ca(BH4)2 Anode for All Solid State Batteries

AbstractAll‐solid‐state batteries have gained considerable attention due to their high safety and energy density. However, solid state electrolytes which contribute to the ionic conductivity component of a composite electrode, are not utilized during the electrode reaction and cannot directly contribute to capacity. This study focuses on decreasing the amount of electrolyte in the electrode by utilizing Ca(BH4)2 as an active electrode material. In this work, the charge‐discharge properties of Ca(BH4)2 as an electrode material were determined for the first time. The lithiation of the Ca(BH4)2 anode creates LiBH4 within the electrode mixture, providing new Li‐ion conduction pathways within the composite electrode in situ. An electrode fabricated only from Ca(BH4)2 and acetylene black (AB) showed an initial capacity of 473 mAh g−1 at 120 °C, which is comparable to the performance obtained from a composite electrode additionally containing electrolyte. Evidently, Ca(BH4)2 is a promising candidate negative electrode for increased energy density all‐solid‐state Li‐ion batteries.

A superior sodium-ion anode material from PAN/lignin-derived carbon nanofibers with inter-connected structure prepared through phosphoric acid induced cross-linking

A feasible route to fabricate phosphorus-doped carbon nanofibers (P-CNFs) with an inter-connected structure has been demonstrated through electrospinning, stabilization, and subsequent phosphoric acid impregnation and carbonization processes using polyacrylonitrile and lignin as carbon sources. The results illustrate that the phosphoric acid induced cross-linking could be beneficial to acquire the closed-pore structure and the heteroatom-doped surface chemistry of nanofibers. As a result, the P-CNFs exhibit higher interlayer spacing of graphite and lower BET specific surface area compared to the pristine CNFs. The P-CNFs as an anode material for sodium-ion batteries (SIBs) present a high reversible capacity 278 mA h g−1 at 0.2 A g−1 and a superior initial Coulomb efficiency (ICE) of 78.86 %. Moreover, the reversible capacity of P-CNFs can be stably maintained near the initial capacity after 5000 cycles at 1 A g−1, showing exceptional structural stability and cycling durability. Meanwhile, the sodium storage mechanism of P-CNFs was investigated using in-situ Raman and ex-situ XRD analysis to understand the exceptional structural stability and Na+ adsorption capacity of P-CNFs. This work provides valuable insights for the design of carbon nanofibers with an inter-connected structure as anode materials for SIBs, exhibiting outstanding electrochemical properties.

Facilitating prelithiation of silicon carbon anode by localized high‐concentration electrolyte for high‐rate and long‐cycle lithium storage

AbstractThe commercialization of silicon‐based anodes is affected by their low initial Coulombic efficiency (ICE) and capacity decay, which are attributed to the formation of an unstable solid electrolyte interface (SEI) layer. Herein, a feasible and cost‐effective prelithiation method under a localized high‐concentration electrolyte system (LHCE) for the silicon–silica/graphite (Si–SiO2/C@G) anode is designed for stabilizing the SEI layer and enhancing the ICE. The thin SiO2/C layers with –NH2 groups covered on nano‐Si surfaces are demonstrated to be beneficial to the prelithiation process by density functional theory calculations and electrochemical performance. The SEI formed under LHCE is proven to be rich in ionic conductivity, inorganic substances, and flexible organic products. Thus, faster Li+ transportation across the SEI further enhances the prelithiation effect and the rate performance of Si–SiO2/C@G anodes. LHCE also leads to uniform decomposition and high stability of the SEI with abundant organic components. As a result, the prepared anode shows a high reversible specific capacity of 937.5 mAh g−1 after 400 cycles at a current density of 1 C. NCM 811‖Li‐SSG‐LHCE full cell achieves a high‐capacity retention of 126.15 mAh g−1 at 1 C over 750 cycles with 84.82% ICE, indicating the great value of this strategy for Si‐based anodes in large‐scale applications.

Stable Flexible Electronic Devices under Harsh Conditions Enabled by Double-Network Hydrogels Containing Binary Cations.

Hydrogels are increasingly used in flexible electronic devices, but the mechanical and electrochemical stabilities of hydrogel devices are often limited under specific harsh conditions. Herein, chemically/physically cross-linked double-network (DN) hydrogels containing binary cations Zn2+ and Li+ are constructed in order to address the above challenges. Double networks of chemically cross-linked polyacrylamide (PAM) and physically cross-linked κ-Carrageenan (κ-CG) are designed to account for the mechanical robustness while binary cations endow the hydrogels with excellent ionic conductivity and outstanding environmental adaptability. Excellent mechanical robustness and ionic conductivity (25 °C, 2.26 S·m-1; -25 °C, 1.54 S·m-1) have been achieved. Utilizing the DN hydrogels containing binary cations as signal-converting materials, we fabricated flexible mechanosensors. High gauge factors (resistive strain sensors, 2.4; capacitive pressure sensors, 0.82 kPa-1) and highly stable sensing ability have been achieved. Interestingly, zinc-ion hybrid supercapacitors containing the DN hydrogels containing binary cations as electrolytes have achieved an initial capacity of 52.5 mAh·g-1 at a current density of 3 A·g-1 and a capacity retention rate of 82.9% after 19,000 cycles. Proper working of the zinc-ion hybrid supercapacitors at subzero conditions and stable charge-discharge for more than 19,000 cycles at -25 °C have been demonstrated. Overall, DN hydrogels containing binary cations have provided promising materials for high-performance flexible electronic devices under harsh conditions.

High-vacancy-type titanium oxycarbide for large-capacity lithium-ion storage

Electrochemical processes involving the ion insertion/desertion are usually accompanied by composition variation and structural evolution of electrode materials. Here we propose a meaningful lattice regulation by inserting lithium ions to unlock an active crystalline plane from which high energy storage performance can be obtained. A rock-salt titanium oxycarbide featuring 12% titanium vacancies (Ti0.88□0.12C0.63O0.37) in high active (011) crystalline plane bears excellent electrochemical activity that enables additional reversible lithium insertion, providing a high initial specific capacity of 390 mAh g−1 at 0.05 A g−1. EPR, XAS, PDF and TEM measurements confirm abundant titanium vacancies, electrochemical studies combined with computational calculations demonstrate high activity of (011) crystalline plane as domain channels for lithium-ion insertion, and ex-situ XRD investigations disclose structural evolution during lithium-ion insertion/desertion. Notably, the repeated lithium-ion insertion/desertion promotes new exposure of (011) crystalline planes, leading to a capacity “negative fading” from the initial 120 to 325 mAh g−1 after 1100 cycles at 0.5 A g−1. The study presents the inner relationship between material microstructural transformation and electrochemical properties, providing a new perspective for mechanism re-understanding and structure development of ion-storage electrode materials.

The hydrothermal synthesis of d-Ti3CN/V2O5 hollow spheres for enhanced supercapacitors applications

In this work, d-Ti3CN MXene was obtained by selective etching of Al from Ti3AlCN by hydrofluoric acid, and a hydrothermal method was employed to prepare d-Ti3CN/V2O5 hollow spheres. The prepared d-Ti3CN/V2O5 hollow spheres showed enhanced electrochemical properties. V2O5 hollow spheres expanded the distance between d-Ti3CN MXene sheets, leading to fast electron transport and improved electrochemical performance of d-Ti3CN/V2O5 hollow spheres. A specific capacitance of 340 F g−1 was achieved at 1 A g−1 current density, which is higher than that of d-Ti3CN MXene (321 F g−1) and V2O5 hollow sphere (155 F g−1). The initial capacitance retention is 89 % after 6000 cycles of constant current charge and discharge at the current density of 10 A g−1. In short, d-Ti3CN/V2O5 hollow spheres show excellent supercapacitor performance regarding specific capacitance and stability.

MOF-Derived Bimetallic Selenide CoNiSe2 Nanododecahedrons Encapsulated in Porous Carbon Matrix as Advanced Anodes for Lithium-Ion Batteries.

Transition metal selenides have received considerable attention as promising candidates for lithium-ion battery (LIB) anode materials due to their high theoretical capacity and safety characteristics. However, their commercial viability is hampered by insufficient conductivity and volumetric fluctuations during cycling. To address these issues, we have utilized bimetallic metal-organic frameworks to fabricate CoNiSe2/C nanodecahedral composites with a high specific surface area, abundant pore structures, and a surface-coated layer of the carbon-based matrix. The optimized material, CoNiSe2/C-700, exhibited impressive Li+ storage performance with an initial discharge specific capacity of 2125.5 mA h g-1 at 0.1 A g-1 and a Coulombic efficiency of 98% over cycles. Even after 1000 cycles at 1.0 A g-1, a reversible discharge specific capacity of 549.9 mA h g-1 was achieved. The research highlights the synergistic effect of bimetallic selenides, well-defined nanodecahedral structures, stable carbon networks, and the formation of smaller particles during initial cycling, all of which contribute to improved electronic performance, reduced volume change, increased Li+ storage active sites, and shorter Li+ diffusion paths. In addition, the pseudocapacitance behavior contributes significantly to the high energy storage of Li+. These features facilitate rapid charge transfer and help maintain a stable solid-electrolyte interphase layer, which ultimately leads to an excellent electrochemical performance. This work provides a viable approach for fabricating bimetallic selenides as anode materials for high-performance LIBs through architectural engineering and compositional tailoring.

Simultaneously manipulating carbon coating layers and void structures in silicon/carbon anode materials via bifunctional templates for lithium-ion batteries

The carbon coating strategies, ameliorating structure instability and reaction kinetics of silicon anodes upon lithiation/delithiation, have been chronically plagued by an electrochemical contradiction between a high specific capacity from a high silicon content and a long cycle life from a high carbon content. Herein, the carbon coating layers and void structures for silicon/carbon composites were simultaneously manipulated through a precisely grown Al2O3 template, which induced a controllable polydopamine polymerization through its mild interfacial interaction with Tris-buffer solution and created abundant void spaces by its residual parts. Particularly, the as-optimized silicon/carbon composite with an ultrahigh silicon content of 89.3 wt% could demonstrate a large initial reversible capacity of 2583 mAh g−1 with an 82.1 % coulombic efficiency at 200 mA g−1, a remarkable cycling durability of 601 mAh g−1 after 990 cycles at 2000 mA g−1, and an excellent rate capability of 887 mAh g−1 at 4000 mA g−1. The uniform void structures could maintain the structural stability/integrity of silicon, boost reaction kinetics across electrode/electrolyte interfaces, and suppress the uncontrollable formation/evolution of solid electrolyte interphases upon cycling. This novel research on synchronously regulating carbon layers and void structures in silicon/carbon composites would enlighten a rational development of high-capacity and long-life silicon anodes.

Quantum Spin Exchange Interactions to Accelerate the Redox Kinetics in Li–S Batteries

HighlightsCompared with the traditional single-atom catalysts (SACs), the Mg SACs with axial displacement is accurately fabricated on the functional carbon nanotubes.The electronic spin polarization modulates the spin density of MgPc, facilitating the LiPSs conversion kinetics in Li-S batteries.The MgPc@FCNT achieves ultra-low capacity decay rate under the high sulfur loading.

Fluorine-Free Lithium-Ion Capacitor with Enhanced Sustainability and Safety Based on Bio-Based ƴ-Valerolactone and Lithium Bis(Oxalato)Borate Electrolyte.

In this work, the properties of a novel electrolyte based on the combination of bio-based ƴ-valerolactone (GVL) solvent with lithium bis(oxalato)borate (LiBOB) salt and its use for lithium-ion capacitors (LICs) are presented. It is shown that the 1 m LiBOB in GVL electrolyte displays good transport properties, high thermal stability, and the ability to prevent anodic dissolution. Its impact on the performance of both battery-type and capacitive-type electrodes is evaluated. In this regard, special attention is paid to the filming properties associated with LiBOB and GVL decomposition at the electrode surfaces. To the best of the authors' knowledge, the full-cell devices assembled in this study are the first example of a fluorine-free LIC. These devices exhibit a favorable energy-to-power ratio, delivering 80Whkg-1 AM at 10000Wkg-1 AM along with excellent cycling stability, retaining 80% of the initial capacitance after 25000 cycles. Furthermore, post-mortem analysis of the LIC electrodes is conducted to gain deeper insights into the degradation mechanisms within the device.

Catalyzing Battery Materials Research via Lab‐Made, Sub‐Ampere‐Hour‐Scale Pouch Cells, and Long‐Term Electrochemical Monitoring by a Reparable Reference Electrode

AbstractBattery materials research is of crucial importance to the development of next‐generation batteries. However, the transition from lab‐scale studies, typically in gram quantities, to industrially relevant ones (i.e., kilogram scale) has been holding back by challenges in scale‐up synthesis and a lack of reliable approaches to verify the electrochemical performance of the lab‐made materials. Here the design and assembly procedures of sub‐Ah‐scale pouch cells that provide validations of several lab‐made Li‐ion and Na‐ion cathode materials available in a limited quantity (<5 g) are reported. These lab‐made pouch cells show superior cycle stability and consistency over the widely used coin cells, exemplified by multiple Ni‐rich layered oxide‐graphite full batteries retaining 84.29 ± 0.16% of the initial capacities over 1000 cycles. A four‐electrode pouch cell with a reparable reference electrode is further designed to monitor impedance growth and Li plating during long‐term electrochemical tests. It can be further integrated with in situ ultrasonic imaging to enable multi‐modal studies. This work provides a powerful platform to evaluate and boost the technology readiness levels of laboratory‐discovered battery materials.

An ambient‐temperature superionic conductive, electrochemically stable, plastic cross‐linked polymer electrolyte for lithium metal battery

AbstractA plastic cross‐linked polymer is prepared using acrylonitrile as a monomer and poly(ethylene glycol diacrylate) as a linking agent. A phase diagram‐guide rational design is introduced to fabricate the polymer composite electrolyte in the case of succinonitrile complexed with lithium bis‐trifluoromethanesulfonimide. The plastic cross‐linked polymer‐based electrolyte films with ambient‐temperature superionic conductivity (2.33 mS cm−1) and a wide electrochemical window (0–5.6 V vs. Li/Li+) have been demonstrated. The charging and discharging experiments of the plastic polymer composite electrolyte‐based lithium batteries show that the plastic polymer electrolyte can cycle normally and safely at a current density of 0.5 mA cm−2. These batteries exhibit excellent average coulombic efficiency of 98.5% in the first 150 cycles. The initial capacity at 25°C is 127.5 mAh g−1 (0.2 C), which is close to the value achieved by liquid‐electrolyte‐based cells under similar conditions. The capacity retention is 91% after 150 cycles.