首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Sodium‐based dual‐ion batteries (SDIBs) have attracted much attention for their advantages of high operating voltage, environmental friendliness, and especially low cost. However, the electrochemical performances of the reported SDIBs are still unsatisfied due to the decomposition problem of traditional liquid electrolyte under high working voltage. Development of quasi‐solid‐state electrolytes (QSSEs) with excellent electrochemical stability at high voltage is a possible means to improve their properties. In this work, a flexible SDIB based on a QSSE, consisting of poly(vinylidene ?uoride‐co‐hexa?uoropropylene) (PVDF‐HFP) three‐dimensionally cross‐linked with Al2O3 nanoparticles, which exhibits a porous 3D structure with dramatically enhanced ionic conductivity up to ≈1.3 × 10?3 S cm?1, facilitating fast ionic migration of both anions and cations, is reported. This quasi‐state SDIB exhibits a high specific capacity of 96.8 mAh g?1 at a current rate of 5 C and excellent cycling stability with a capacity retention of 97.5% after 600 cycles at 5 C, which is the best performance of the SDIBs. Moreover, excellent flexibility and a wide working temperature range (?20 to 70 °C) have been realized for this battery, suggesting its potential for high‐performance flexible energy storage applications.  相似文献   

2.
All‐solid‐state lithium metal batteries (ASSLMBs) have attracted significant attention due to their superior safety and high energy density. However, little success has been made in adopting Li metal anodes in sulfide electrolyte (SE)‐based ASSLMBs. The main challenges are the remarkable interfacial reactions and Li dendrite formation between Li metal and SEs. In this work, a solid‐state plastic crystal electrolyte (PCE) is engineered as an interlayer in SE‐based ASSLMBs. It is demonstrated that the PCE interlayer can prevent the interfacial reactions and lithium dendrite formation between SEs and Li metal. As a result, ASSLMBs with LiFePO4 exhibit a high initial capacity of 148 mAh g?1 at 0.1 C and 131 mAh g?1 at 0.5 C (1 C = 170 mA g?1), which remains at 122 mAh g?1 after 120 cycles at 0.5 C. All‐solid‐state Li‐S batteries based on the polyacrylonitrile‐sulfur composite are also demonstrated, showing an initial capacity of 1682 mAh g?1. The second discharge capacity of 890 mAh g?1 keeps at 775 mAh g?1 after 100 cycles. This work provides a new avenue to address the interfacial challenges between Li metal and SEs, enabling the successful adoption of Li metal in SE‐based ASSLMBs with high energy density.  相似文献   

3.
Rechargeable all‐solid‐state batteries will play a key role in many autonomous devices. Planar solid‐state thin film batteries are rapidly emerging but reveal several drawbacks, such as a relatively low energy density and the use of highly reactive metallic lithium. In order to overcome these limitations a new 3D‐integrated all‐solid‐state battery concept with significantly increased surface area is presented. By depositing the active battery materials into high‐aspect ratio structures etched in, for example silicon, 3D‐integrated all‐solid‐state batteries are calculated to reach a much higher energy density. Additionally, by adopting novel high‐energy dense Li‐intercalation materials the use of metallic Lithium can be avoided. Sputtered Ta, TaN and TiN films have been investigated as potential Li‐diffusion barrier materials. TiN combines a very low response towards ionic Lithium and a high electronic conductivity. Additionally, thin film poly‐Si anodes have been electrochemically characterized with respect to their thermodynamic and kinetic Li‐intercalation properties and cycle life. The Butler‐Vollmer relationship was successfully applied, indicating favorable electrochemical charge transfer kinetics and solid‐state diffusion. Advantageously, these new Li‐intercalation anode materials were found to combine an extremely high energy density with fast rate capability, enabling future 3D‐integrated all‐solid‐state batteries.  相似文献   

4.
Owing to an absence or lack of soft (and/or liquid) components, electrochemo‐mechanical effects are imperative for all‐solid‐state batteries (ASBs) based on inorganic solid electrolytes (SEs). As this aspect has been overlooked, relevant investigation has remained scarce. In this work, the development of a new operando differential electrochemical pressiometry (DEP) for ASBs is reported. The time‐ (or capacity‐) derivative differential pressure signals (dP/dt or dP/dQ) reflecting corresponding differential volume changes of electrode active materials feature the specific state of charges (SOCs). This finding leads to a precise estimation of the SOCs of graphite (Gr) electrodes in LiNi0.70Co0.15Mn0.15O2 (NCM)/Gr all‐solid‐state full cells using sulfide SEs with varying capacity ratios of negative to positive electrodes (n/p ratios); this is corroborated by complementary analysis using a three‐electrode electrochemical cell and ex situ X‐ray diffraction measurements. Furthermore, electrochemo‐mechanical behaviors of NCM/Gr full cells with Gr electrodes employing SEs excluding or including reductively unstable Li10GeP2S12 are investigated. Notable volume changes caused by lithiation of Li10GeP2S12 are detected. Importantly, significantly delayed SOC for Gr caused by a severe side reaction with Li10GeP2S12 is disclosed by the operando DEP result.  相似文献   

5.
High energy density, durability, and flexibility of supercapacitors are required urgently for the next generation of wearable and portable electronic devices. Herein, a novel strategy is introduced to boost the energy density of flexible soild‐state supercapacitors via rational design of hierarchically graphene nanocomposite (GNC) electrode material and employing an ionic liquid gel polymer electrolyte. The hierarchical graphene nanocomposite consisting of graphene and polyaniline‐derived carbon is synthesized as an electrode material via a scalable process. The meso/microporous graphene nanocomposites exhibit a high specific capacitance of 176 F g?1 at 0.5 A g?1 in the ionic liquid 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIBF4) with a wide voltage window of 3.5 V, good rate capability of 80.7% in the range of 0.5–10 A g?1 and excellent stability over 10 000 cycles, which is attributed to the superior conductivity (7246 S m?1), and quite large specific surface area (2416 m2 g?1) as well as hierarchical meso/micropores distribution of the electrode materials. Furthermore, flexible solid‐state supercapacitor devices based on the GNC electrodes and gel polymer electrolyte film are assembled, which offer high specific capacitance of 180 F g?1 at 1 A g?1, large energy density of 75 Wh Kg?1, and remarkable flexible performance under consecutive bending conditions.  相似文献   

6.
A new class of highly thin, deformable, and safety‐reinforced plastic crystal polymer electrolytes (N‐PCPEs) is demonstrated as an innovative solid electrolyte for potential use in high‐performance flexible lithium‐ion batteries with aesthetic versatility and robust safety. The unusual N‐PCPEs are fabricated by combining a plastic crystal polymer electrolyte with a porous polyethylene terephthalate (PET) nonwoven. Herein, the three‐dimensional reticulated plastic crystal polymer electrolyte matrix is formed directly inside the PET nonwoven skeleton via in‐situ UV‐crosslinking of ethoxylated trimethylolpropane triacrylate (ETPTA) monomer, under co‐presence of plastic crystal electrolyte. The PET nonwoven is incorporated as a compliant skeleton to enhance mechanical/dimensional strength of N‐PCPE. Owing to this structural uniqueness, the N‐PCPE shows significant improvements in the film thickness and deformability with maintaining advantageous features (such as high ionic conductivity and thermal stability) of the PCE. Based on structural/physicochemical characterization of N‐PCPE, its potential application as a solid electrolyte for flexible lithium‐ion batteries is explored by scrutinizing the electrochemical performance of cells. The high ionic conductance of N‐PCPE, along with its excellent deformability, plays a viable role in improving cell performance (particularly at high current densities and also mechanically deformed states). Notably, the cell assembled with N‐PCPE exhibits stable electrochemical performance even under a severely wrinkled state, without suffering from internal short‐circuit failures between electrodes.  相似文献   

7.
8.
Poly(ethylene oxide) (PEO)‐based solid electrolytes are expected to be exploited in solid‐state batteries with high safety. Its narrow electrochemical window, however, limits the potential for high voltage and high energy density applications. Herein the electrochemical oxidation behavior of PEO and the failure mechanisms of LiCoO2‐PEO solid‐state batteries are studied. It is found that although for pure PEO it starts to oxidize at a voltage of above 3.9 V versus Li/Li+, the decomposition products have appropriate Li+ conductivity that unexpectedly form a relatively stable cathode electrolyte interphase (CEI) layer at the PEO and electrode interface. The performance degradation of the LiCoO2‐PEO battery originates from the strong oxidizing ability of LiCoO2 after delithiation at high voltages, which accelerates the decomposition of PEO and drives the self‐oxygen‐release of LiCoO2, leading to the unceasing growth of CEI and the destruction of the LiCoO2 surface. When LiCoO2 is well coated or a stable cathode LiMn0.7Fe0.3PO4 is used, a substantially improved electrochemical performance can be achieved, with 88.6% capacity retention after 50 cycles for Li1.4Al0.4Ti1.6(PO4)3 coated LiCoO2 and 90.3% capacity retention after 100 cycles for LiMn0.7Fe0.3PO4. The results suggest that, when paired with stable cathodes, the PEO‐based solid polymer electrolytes could be compatible with high voltage operation.  相似文献   

9.
10.
Solid‐state lithium (Li) batteries using solid electrolytes and Li anodes are highly desirable because of their high energy densities and intrinsic safety. However, low ambient‐temperature conductivity and poor interface compatibility of solid electrolytes as well as Li dendrite formation cause large polarization and poor cycling stability. Herein, a high transference number intercalated composite solid electrolyte (CSE) is prepared by the combination of a solution‐casting and hot‐pressing method using layered lithium montmorillonite, poly(ethylene carbonate), lithium bis(fluorosulfonyl)imide, high‐voltage fluoroethylene carbonate additive, and poly(tetrafluoroethylene) binder. The electrolyte presents high ionic conductivity (3.5 × 10?4 S cm?1), a wide electrochemical window (4.6 V vs Li+/Li), and high ionic transference number (0.83) at 25 °C. In addition, a 3D Li anode is also fabricated via a facile thermal infusion strategy. The synergistic effect of high transference number intercalated electrolyte and 3D Li anode is more favorable to suppress Li dendrites in a working battery. The solid‐state batteries based on LiFePO4 (Al2O3 @ LiNi0.5Co0.2Mn0.3O2), CSE, and 3D Li deliver admirable cycling stability with discharge capacity 145.9 mAh g?1 (150.7 mAh g?1) and capacity retention 91.9% after 200 cycles at 0.5 C (92.0% after 100 cycles at 0.2 C) at 25 °C. This work affords a splendid strategy for high‐performance solid‐state battery.  相似文献   

11.
Scientific and technological interest in solid‐state Li metal batteries (SSLMBs) arises from their excellent safety and promising high energy density. However, the practical application of SSLMBs is hindered by poor contact between the Li metal anode (LMA) and solid‐state electrolytes (SSEs). To circumvent this limitation, a pattern‐guided approach that shapes the LMA/SSE contact is disclosed to offer fast Li ion conduction in the interface. A thermally‐treated copper foam is used as the lithophilic pattern to confine and guide Li for forming a tight contact with garnet‐type SSE. The contact can be easily manipulated according to the shape of lithiophilic pattern, facilitating cell assembly. The resulting Li|patterned garnet|Li symmetric cell exhibits an interfacial resistance of 9.8 Ω cm2, which is dramatically lower than that of 998 Ω cm2 for Li|pristine garnet|Li symmetric cell. Being used in Li–sulfur batteries, the patterned garnet effectively eliminates the polysulfide shuttle and enables stable cycling performance, showing a low capacity decay of 0.035% per cycle over 1000 cycles. The fundamental contact process of metallic anodes/SSEs is carefully investigated. This contact strategy provides a new design concept to improve the interface wettability via a lithiophilic pattern for a variety of SSEs that cannot wet with metallic anodes.  相似文献   

12.
SnSx (x = 1, 2) compounds are composed of earth‐abundant elements and are nontoxic and low‐cost materials that have received increasing attention as energy materials over the past decades, owing to their huge potential in batteries. Generally, SnSx materials have excellent chemical stability and high theoretical capacity and reversibility due to their unique 2D‐layered structure and semiconductor properties. As a promising matrix material for storing different alkali metal ions through alloying/dealloying reactions, SnSx compounds have broad electrochemical prospects in batteries. Herein, the structural properties of SnSx materials and their advantages as electrode materials are discussed. Furthermore, detailed accounts of various synthesis methods and applications of SnSx materials in lithium‐ion batteries, sodium‐ion batteries, and other new rechargeable batteries are emphasized. Ultimately, the challenges and opportunities for future research on SnSx compounds are discussed based on the available academic knowledge, including recent scientific advances.  相似文献   

13.
Ion gel electrolytes show great potential in solid‐state batteries attributed to their outstanding characteristics. However, because of the strong ionic nature of ionic liquids, ion gel electrolytes generally exhibit low lithium‐ion transference number, limiting its practical application. Amine‐functionalized boron nitride (BN) nanosheets (AFBNNSs) are used as an additive into ion gel electrolytes for improving their ion transport properties. The AFBNNSs‐ion gel shows much improved mechanical strength and thermal stability. The lithium‐ion transference number is increased from 0.12 to 0.23 due to AFBNNS addition. More importantly, for the first time, nuclear magnetic resonance analysis reveals that the amine groups on the BN nanosheets have strong interaction with the bis(trifluoromethanesulfonyl)imide anions, which significantly reduces the anion mobility and consequently increases lithium‐ion mobility. Battery cells using the optimized AFBNNSs‐ion gel electrolyte exhibit stable lithium deposition and excellent electrochemical performance. A LiFePO4|Li cell retains 92.2% of its initial specific capacity after the 60th cycle while the cell without AFBNNSs‐gel electrolyte only retains 53.5%. The results not only demonstrate a new strategy to improve lithium‐ion transference number in ionic liquid electrolytes, but also open up a potential avenue to achieve solid‐state lithium metal batteries with improved performance.  相似文献   

14.
Solid‐state lithium polymer secondary batteries (LPB) are fabricated with a two‐electrode‐type cell construction of Li|solid‐state polymer electrolyte (SPE)|LiFePO4. Plasticizers of poly(ethylene glycol) (PEG)‐borate ester (B‐PEG) or PEG‐aluminate ester (Al‐PEG) are added into lithium‐conducting SPEs in order to enhance their ionic conductivity, and lithium bis‐trifluoromethansulfonimide (LiTFSI) is used as the lithium salt. An improvement of the electrochemical properties is observed upon addition of the plasticizers at an operation temperature of 60 °C. However, a decrease of discharge capacities abruptly follows after tens of stable cycles. To understand the origin of the capacity fading, electrochemical impedance techniques, ex‐situ NMR and scanning electron microscopy (SEM)/energy dispersive X‐ray spectroscopy (EDS) techniques are adopted. Alternating current (AC) impedance measurements indicate that the decrease of capacity retention in the LPB is related to a severe increase of the interfacial resistance between the SPE and cathode. In addition, the bulk resistance of the SPE film is observed to accompany the capacity decay. Ex situ NMR studies combined with AC impedance measurements reveal a decrease of Li salt concentration in the SPE film after cycling. Ex situ SEM/EDS observations show an increase of concentration of anions on the electrode surface after cycling. Accordingly, the anions may decompose on the cathode surface, which leads to a reduction of the cycle life of the LPB. The present study suggests that a choice of Li salt and an increase of transference number is crucial for the realization of lithium polymer batteries.  相似文献   

15.
Solid‐state lithium–sulfur battery (SSLSB) is attractive due to its potential for providing high energy density. However, the cell chemistry of SSLSB still faces challenges such as sluggish electrochemical kinetics and prominent “chemomechanical” failure. Herein, a high‐performance SSLSB is demonstrated by using the thio‐LiSICON/polymer composite electrolyte in combination with sulfurized polyacrylonitrile (S/PAN) cathode. Thio‐LiSICON/polymer composite electrolyte, which processes high ionic conductivity and wettability, is fabricated to enhance the interfacial contact and the performance of lithium metal anodes. S/PAN is utilized due to its unique electrochemical characteristics: electrochemical and structural studies combined with nuclear magnetic resonance spectroscopy and electron paramagnetic resonance characterizations reveal the charge/discharge mechanism of S/PAN, which is the radical‐mediated redox reaction within the sulfur grafted conjugated polymer framework. This characteristic of S/PAN can support alleviating the volume change in the cathode and maintaining fast redox kinetics. The assembled SSLSB full cell exhibits excellent rate performance with 1183 mAh g?1 at 0.2 C and 719 mAh g?1 at 0.5 C, respectively, and can accomplish 50 cycles at 0.1 C with the capacity retention of 588 mAh g?1. The superior performance of the SSLSB cell rationalizes the construction concept and leads to considerations for the innovative design of SSLSB.  相似文献   

16.
Anatase TiO2 is considered as one of the promising anodes for sodium‐ion batteries because of its large sodium storage capacities with potentially low cost. However, the precise reaction mechanisms and the interplay between surface properties and electrochemical performance are still not elucidated. Using multimethod analyses, it is herein demonstrated that the TiO2 electrode undergoes amorphization during the first sodiation and the amorphous phase exhibits pseudocapacitive sodium storage behaviors in subsequent cycles. It is also shown that the pseudocapacitive sodium storage performance is sensitive to the nature of solid electrolyte interphase (SEI) layers. For the first time, it is found that ether‐based electrolytes enable the formation of thin (≈2.5 nm) and robust SEI layers, in contrast to the thick (≈10 nm) and growing SEI from conventional carbonate‐based electrolytes. First principle calculations suggest that the higher lowest unoccupied molecular orbital energies of ether solvents/ion complexes are responsible for the difference. TiO2 electrodes in ether‐based electrolyte present an impressive capacity of 192 mAh g?1 at 0.1 A g?1 after 500 cycles, much higher than that in carbonate‐based electrolyte. This work offers the clarified picture of electrochemical sodiation mechanisms of anatase TiO2 and guides on strategies about interfacial control for high performance anodes.  相似文献   

17.
The development of flexible supercapacitors with high volumetric performance is critically important for portable electronics applications, which are severely volume limited. Here, dead‐end tube membrane (DETM) ultrafiltration is used to produce densely compacted carbon‐nanotube/graphene fibrous films as solid‐state supercapacitor electrodes. DETM is widely used in the water purification industry, but to date its use has not been explored for making supercapacitor electrode materials. Compared with vacuum‐assisted filtration, dead‐end filtration of the mixture through a porous membrane is carried out under much higher pressure, and thus the solvent can be gotten rid of much faster, with less energy consumption and in an environmentally friendly manner. More importantly, phase separation of the solid constituents in the mixture, due to concentration increase, can be suppressed in DETM. Therefore, highly uniform and densely compacted supercapacitor electrodes can be obtained with very high volumetric energy and power density. The volumetric energy density in this work (≈2.7 mWh cm‐3) is at a higher level than all the all‐solid‐state fibrous supercapacitors reported to date. This can be attributed to the DETM process used, which produces a densely compacted network structure without compromising the availability of electrochemically active surface area.  相似文献   

18.
The emergence of nanomaterials in the past decades has greatly advanced modern energy storage devices. Nanomaterials can offer high capacity and fast kinetics yet are prone to rapid morphological evolution and degradation. As a result, they are often hybridized with a stable framework in order to gain stability and fully utilize its advantages. However, candidates for such framework materials are rather limited, with carbon, conductive polymers, and Ti‐based oxides being the only choices; note these are all inactive or intercalation compounds. Conventionally, alloying‐/conversion‐type electrodes, which are thought to be electrochemically unstable by themselves, have never been considered as framework materials. This concept is challenged. Successful application of conversion‐type MnO nanorod as a anode framework for high‐capacity Mo2C/MoOx nanoparticles has been demonstrated in sodium‐ion batteries. Surprisingly, it can stably deliver 110 mAh g?1 under extremely high rate of 8000 mA g?1 (≈70 C) over 40 000 cycles with no capacity decay. More generally, this is considered as a proof of concept and much more alloying‐/conversion‐type materials are expected to be explored for such applications.  相似文献   

19.
A high‐performance graphene oxide (GO)‐doped ion gel (P(VDF‐HFP)‐EMIMBF4‐GO gel) is prepared by exploiting copolymer (poly(vinylidene fluoride‐hexafluoro propylene), P(VDF‐HFP)) as the polymer matrix, ionic liquid (1‐ethyl‐3‐methylimidazolium tetrafluoroborate, EMIMBF4) as the supporting electrolyte, and GO as the ionic conducting promoter. This GO‐doped ion gel demonstrates significantly improved ionic conductivity compared with that of pure ion gel without the addition of GO, due to the homogeneously distributed GO as a 3D network throughout the GO‐doped ion gel by acting like a ion “highway” to facilitate the ion transport. With the incorporation of only a small amount of GO (1 wt%) in ion gel, there has been a dramatic improvement in ionic conductivity of about 260% compared with that of pure ion gel. In addition, the all‐solid‐state supercapacitor is fabricated and measured at room temperature using the GO‐doped ion gel as gel polymer electrolyte, which demonstrates more superior electrochemical performance than the all‐solid‐state supercapacitor with pure ion gel and the conventional supercapacitor with neat EMIMBF4, in the aspect of smaller internal resistance, higher capacitance performance, and better cycle stability. These excellent performances are due to the high ionic conductivity, excellent compatibility with carbon electrodes, and long‐term stability of the GO‐doped ion gel.  相似文献   

20.
Polymer blends based solid polymer electrolytes (SPEs), combining the advantages of multiple polymers, are promising for the utilization of 5 V-class cathodes (e.g., LiCoMnO4 (LCMO)) with enhanced safety. However, severe macro-phase separation with defects and voids in polymer blends restrict the electrochemical stability and ionic migration of SPEs. Herein, inorganic compatibilizer polyacrylonitrile grafted MXene (MXene-g-PAN) is exploited to improve the miscibility of the poly(vinylidene fluoride-co-hexafluoropropylene) (PVHF)/PAN blends and suppress the consolidation of phase particles. The resulting SPE exhibits a high anodic stability with an ionic conductivity of 2.17 × 10−4 S cm−1, enabling a stable and reversible Li platting/stripping (over 2500 h). The fabricated solid Li‖LCMO cell delivers a 5.1 V discharge voltage with a decent capacity (131 mAh g−1) and cycling performance. Subsequently, the solid all-in-one graphite‖LCMO battery is also constructed to extend the application of MXene based SPEs in flexible batteries. Benefiting from the interface-less design, outstanding mechanical flexibility and stability is achieved in the battery, which can endure various deformations with a low-capacity loss (< ≈10%). This study signifies a significant development on solid flexible lithium ion batteries with enhanced performance, stability, and reliability by investigating the miscibility of polymer blends, benefiting for the design of high-performance SPEs.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号