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1.
Electrolyte design has become ever more important to enhance the performance of lithium-ion batteries (LIBs). However, the flammability issue and high reactivity of the conventional electrolytes remain a major problem, especially when the LIBs are operated at high voltage and extreme temperatures. Herein, we design a novel non-flammable fluorinated ester electrolyte that enables high cycling stability in wide-temperature variations (e.g., −50 °C–60 °C) and superior power capability (fast charge rates up to 5.0 C) for the graphite||LiNi0.8Co0.1Mn0.1O2 (NCM811) battery at high voltage (i.e., >4.3 V vs. Li/Li+). Moreover, this work sheds new light on the dynamic evolution and interaction among the Li+, solvent, and anion at the molecular level. By elucidating the fundamental relationship between the Li+ solvation structure and electrochemical performance, we can facilitate the development of high-safety and high-energy-density batteries operating in harsh conditions.  相似文献   

2.
High-voltage lithium metal batteries (LMBs) pose severe challenges for the matching of electrolytes with aggressive electrodes, especially at low temperatures. Here, we report a rational modification of the Li+ solvation structure to extend the voltage and temperature operating ranges of conventional electrolytes. Ion-ion and ion-dipole interactions as well as the electrochemical window of solvents were tailored to improve oxidation stability and de-solvation kinetics of the electrolyte. Meanwhile, robust and elastic B and F-rich interphases are formed on both electrodes. Such optimization enables Li||LiNi0.5Mn1.5O4 cells (90.2 % retention after 400 cycles) and Li||LiNi0.6Co0.2Mn0.2O2 (NCM622) cells (74.0 % retention after 200 cycles) to cycle stably at an ultra-high voltage of 4.9 V. Moreover, NCM622 cells deliver a considerable capacity of 143.5 mAh g−1 at −20 °C, showing great potential for practical uses. The proposed strategy sheds light on further optimization for high-voltage LMBs.  相似文献   

3.
Ether electrolytes are promising for lithium metal batteries. Despite the intensive research in recent years, most state-of-the-art ether electrolytes still cannot form reliable electrode-electrolyte interfaces in NCM811-Li batteries at diluted concentrations, especially in those operating at elevated temperatures. We report a simple but effective strategy to break this bottleneck and stabilize interfaces in high-temperature NCM811-Li batteries in ether electrolytes. We propose that by gradually extending the terminal groups of glycol diethers from methyl groups to n-butyl groups, the comprehensive stability of ether electrolytes is improved. An anion-dominated solvation structure is realized at a concentration of 1 M. Accordingly, the electrode-electrolyte interactions are suppressed, and a thinner, denser, and more inorganic-rich solid- /cathode-electrolyte interface is achieved. Additionally, the surface phase transition and structural degradation of NCM811 cathode are alleviated. Consequently, in the ethylene glycol dibutyl ether-based electrolyte, the Coulombic efficiency for Li−Cu cells working at 60 °C is boosted to 99.41 % with a cycling life of over 200 cycles. The lifespan of high-temperature NCM811-Li cells is prolonged by more than 400 % with a stable average Coulombic efficiency of 99.77 % at quasi-practical conditions of 50 μm Li, lean electrolyte of 10 μL mAh−1, and medium-high cathode loading of >2.2 mAh cm−2.  相似文献   

4.
High-energy Li metal batteries (LMBs) consisting of Li metal anodes and high-voltage cathodes are promising candidates of the next generation energy-storage systems owing to their ultrahigh energy density. However, it is still challenging to develop high-voltage nonflammable electrolytes with superior anode and cathode compatibility for LMBs. Here, we propose an active diluent-anion synergy strategy to achieve outstanding compatibility with Li metal anodes and high-voltage cathodes by using 1,2-difluorobenzene (DFB) with high activity for yielding LiF as an active diluent to regulate nonflammable dimethylacetamide (DMAC)-based localized high concentration electrolyte (LHCE-DFB). DFB and bis(fluorosulfonyl)imide (FSI) anion cooperate to construct robust LiF-rich solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI), which effectively stabilize DMAC from intrinsic reactions with Li metal anode and enhance the interfacial stability of the Li metal anodes and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes. LHCE-DFB enables ultrahigh Coulombic efficiency (98.7 %), dendrite-free, extremely stable and long-term cycling of Li metal anodes in Li || Cu cells and Li || Li cells. The fabricated NCM811 || Li cells with LHCE-DFB display remarkably enhanced long-term cycling stability and excellent rate capability. This work provides a promising active diluent-anion synergy strategy for designing high-voltage electrolytes for high-energy batteries.  相似文献   

5.
Lithium metal batteries (LMBs) comprising Li metal anode and high-voltage nickel-rich cathode could potentially realize high capacity and power density. However, suitable electrolytes to tolerate the oxidation on the cathode at high cut-off voltage are urgently needed. Herein, we present an armor-like inorganic-rich cathode electrolyte interphase (CEI) strategy for exploring oxidation-resistant electrolytes for sustaining 4.8 V Li||LiNi0.6Co0.2Mn0.2O2 (NCM622) batteries with pentafluorophenylboronic acid (PFPBA) as the additive. In such CEI, the armored lithium borate surrounded by CEI up-layer represses the dissolution of inner CEI moieties and also improves the Li+ conductivity of CEI while abundant LiF is distributed over whole CEI to enhance the mechanical stability and Li+ conductivity compared with polymer moieties. With such robust Li+ conductive CEI, the Li||NCM622 battery delivered excellent stability at 4.6 V cut-off voltage with 91.2 % capacity retention after 400 cycles. The excellent cycling performance was also obtained even at 4.8 V cut-off voltage.  相似文献   

6.
《中国化学快报》2023,34(6):107718
The Ni-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) layered cathodes endow Li-ion batteries (LIBs) with high energy density. However, they usually suffer from limited ion-diffusion and structural instability during cycling. Although doping strategy can effectively alleviate these issues, the coupling effects of multi-element doping and the corresponding performance enhancement mechanism have been yet unclear. Here, we report a Zr/Ti dual-doped NCM811 cathode material (ZT-NCM811), in which Zr-ion is doped into both transition metal (TM) layers and lithium layers and Ti-ion is only distributed in TM layers. The dual-doping can effectively enhance crystal structure stability via inhibiting the lattice collapse along c-axis and decreasing the Li/Ni disorder. Meantime, the lattice oxygen escape is also greatly reduced due to the presence of stronger Zr-O and Ti-O bonds, further mitigating the crystal surface parasitic reactions with electrolyte. The resultant ZT-NCM811 exhibits high specific capacity of 124 mAh/g at even 10 C, much higher than undoped and single-doped NCM811, and a retention of 98.8% at 1 C after 100 cycles. The assembled ZT-NCM811/graphite full cell also delivers superior battery performances and durability.  相似文献   

7.
Cu−Li batteries leveraging the two-electron redox property of Cu can offer high energy density and low cost. However, Cu−Li batteries are plagued by limited solubility and a shuttle effect of Cu ions in traditional electrolytes, which leads to low energy density and poor cycling stability. In this work, we rationally design a solid-state sandwich electrolyte for solid-state Cu−Li batteries, in which a deep-eutectic-solvent gel with high Cu-ion solubility is devised as a Cu-ion reservoir while a ceramic Li1.4Al0.4Ti1.6(PO4)3 interlayer is used to block Cu-ion crossover. Because of the high ionic conductivity (0.55 mS cm−1 at 25 °C), wide electrochemical window (>4.5 V vs. Li+/Li), and high Cu ion solubility of solid-state sandwich electrolyte, a solid-state Cu−Li battery demonstrates a high energy density of 1 485 Wh kgCu−1and long-term cyclability with 97 % capacity retention over 120 cycles. The present study lays the groundwork for future research into low-cost solid-state Cu−Li batteries.  相似文献   

8.
Polymer based quasi-solid-state electrolyte (QSE) has attracted great attention due to its assurance for high safety of rechargeable batteries including lithium metal batteries (LMB). However, it faces the issue of low ionic conductivity of electrolyte and solid-electrolyte-interface (SEI) layer between QSE and lithium anode. Herein, we firstly demonstrate that the ordered and fast transport of lithium ion (Li+) can be realized in QSE. Due to the higher coordination strength of Li+ on tertiary amine (−NR3) group of polymer network than that on carbonyl (−C=O) group of ester solvent, Li+ can diffuse orderly and quickly on −NR3 of polymer, significantly increasing the ionic conductivity of QSE to 3.69 mS cm−1. Moreover, −NR3 of polymer can induce in situ and uniform generation of Li3N and LiNxOy in SEI. As a result, the Li||NCM811 batteries (50 μm Li foil) with this QSE show an excellent stability of 220 cycles at ≈1.5 mA cm−2, 5 times to those with conventional QSE. LMBs with LiFePO4 can stably run for ≈8300 h. This work demonstrates an attractive concept for improving ionic conductivity of QSE, and also provides an important step for developing advanced LMB with high cycle stability and safety.  相似文献   

9.
Carbonate electrolytes have excellent chemical stability and high salt solubility, which are ideally practical choice for achieving high-energy-density sodium (Na) metal battery at room temperature. However, their application at ultra-low temperature (−40 °C) is adversely affected by the instability of solid electrolyte interphase (SEI) formed by electrolyte decomposition and the difficulty of desolvation. Here, we designed a novel low-temperature carbonate electrolyte by molecular engineering on solvation structure. The calculations and experimental results demonstrate that ethylene sulfate (ES) reduces the sodium ion desolvation energy and promotes the forming of more inorganic substances on the Na surface, which promote ion migration and inhibit dendrite growth. At −40 °C, the Na||Na symmetric battery exhibits a stable cycle of 1500 hours, and the Na||Na3V2(PO4)3 (NVP) battery achieves 88.2 % capacity retention after 200 cycles.  相似文献   

10.
Lithium||sulfur (Li||S) batteries are considered as one of the promising next-generation batteries due to the high theoretical capacity and low cost of S cathodes, as well as the low redox potential of Li metal anodes (−3.04 V vs. standard hydrogen electrode). However, the S reduction reaction from S to Li2S leads to limited discharge voltage and capacity, largely hindering the energy density of Li||S batteries. Herein, high-energy Li||S hybrid batteries were designed via an electrolyte decoupling strategy. In cathodes, S electrodes undergo the solid-solid conversion reaction from S to Cu2S with four-electron transfer in a Cu2+-based aqueous electrolyte. Such an energy storage mechanism contributes to enhanced electrochemical performance of S electrodes, including high discharge potential and capacity, superior rate performance and stable cycling behavior. As a result, the assembled Li||S hybrid batteries exhibit a high discharge voltage of 3.4 V and satisfactory capacity of 2.3 Ah g−1, contributing to incredible energy density. This work provides an opportunity for the construction of high-energy Li||S batteries.  相似文献   

11.
Controlling lithium (Li) electrocrystallization with preferred orientation is a promising strategy to realize highly reversible Li metal batteries (LMBs) but lack of facile regulation methods. Herein, we report a high-flux solid electrolyte interphase (SEI) strategy to direct (110) preferred Li deposition even on (200)-orientated Li substrate. Bravais rule and Curie-Wulff principle are expanded in Li electrocrystallization process to decouple the relationship between SEI engineering and preferred crystal orientation. Multi-spectroscopic techniques combined with dynamics analysis reveal that the high-flux CF3Si(CH3)3 (F3) induced SEI (F3-SEI) with high LiF and −Si(CH3)3 contents can ingeniously accelerate Li+ transport dynamics and ensure the sufficient Li+ concentration below SEI to direct Li (110) orientation. The induced Li (110) can in turn further promote the surface migration of Li atoms to avoid tip aggregation, resulting in a planar, dendrite-free morphology of Li. As a result, our F3-SEI enables ultra-long stability of Li||Li symmetrical cells for more than 336 days. Furthermore, F3-SEI modified Li can significantly enhance the cycle life of Li||LiFePO4 and Li||NCM811 coin and pouch full cells in practical conditions. Our crystallographic strategy for Li dendrite suppression paves a path to achieve reliable LMBs and may provide guidance for the preferred orientation of other metal crystals.  相似文献   

12.
Lithium metal batteries (LMBs) have attracted extensive attention owing to their high energy density. However, the uncontrolled volume changes and serious dendrite growth of the Li metal anode have hindered their commercialization. Herein, a three-dimensional Cu foam decorated with Au nanoparticles and conformal graphene layer was designed to tune the Li plating/stripping behaviors. The 3D−Cu conductive host anchored by lithiophilic Au nanoparticles can effectively alleviate the volume expansion caused by the continuous plating/stripping of Li and reduce the nucleation energy barrier. Notably, the conductive graphene not only facilitates the transfer of electrons, but also acts as an ionic rectifier, thereby avoiding the aggregation of local current density and Li+ ions around Au nanoparticles and enabling the uniform Li+ flux. As a result, the G−Au@3D−Cu/Li anode ensures the non-dendritic and homogeneous Li+ plating/stripping. Electrochemical results show that the symmetric G−Au@3D−Cu/Li cell delivers a low voltage hysteresis of 110 mV after 1000 h at 1 mA cm−2. Matched with a layered LiNi0.6Co0.2Mn0.2O2 cathode, the NCM622||G−Au@3D−Cu/Li full cell exhibits a long cycle life of 2000 cycles and an ultra-low capacity decay rate (0.01 % per cycle).  相似文献   

13.
Lithium metal batteries hold great promise for promoting energy density and operating at low temperatures, yet they still suffer from insufficient Li compatibility and slow kinetic, especially at ultra-low temperatures. Herein, we rationally design and synthesize a new amphiphilic solvent, 1,1,2,2-tetrafluoro-3-methoxypropane, for use in battery electrolytes. The lithiophilic segment is readily to solvate Li+ to induce self-assembly of the electrolyte solution to form a peculiar core-shell-solvation structure. Such unique solvation structure not only largely improves the ionic conductivity to allow fast Li+ transport and lower the desolvation energy to enable facile desolvation, but also leads to the formation of a highly robust and conductive inorganic SEI. The resulting electrolyte demonstrates high Li efficiency and superior cycling stability from room temperature to −40 °C at high current densities. Meanwhile, anode-free high-voltage cell retains 87 % capacity after 100 cycles.  相似文献   

14.
《中国化学快报》2023,34(12):108640
Lithium metal batteries (LMBs) are considered to be one of the most promising high-energy-density battery systems. However, their practical application in carbonate electrolytes is hampered by lithium dendrite growth, resulting in short cycle life. Herein, an electrolyte regulation strategy is developed to improve the cyclability of LMBs in carbonate electrolytes by introducing LiNO3 using trimethyl phosphate with a slightly higher donor number compared to NO3 as a solubilizer. This not only allows the formaion of Li+-coordinated NO3 but also achieves the regulation of electrolyte solvation structures, leading to the formation of robust and ion-conductive solid-electrolyte interphase films with inorganic-rich inner and organic-rich outer layers on the Li metal anodes. As a result, high Coulombic efficiency of 99.1% and stable plating/stripping cycling of Li metal anode in Li||Cu cells were realized. Furthermore, excellent performance was also demonstrated in Li||LiNi0.83Co0.11Mn0.06O2 (NCM83) full cells and Cu||NCM83 anode-free cells using high mass-loading cathodes. This work provides a simple interphase engineering strategy through regulating the electrolyte solvation structures for high-energy-density LMBs.  相似文献   

15.
Pyrometallurgy technique is usually applied as a pretreatment to enhance the leaching efficiencies in the hydrometallurgy process for recovering valuable metals from spent lithium-ion batteries. However, traditional pyrometallurgy processes are energy and time consuming. Here, we report a carbothermal shock (CTS) method for reducing LiNi0.3Co0.2Mn0.5O2 (NCM325) cathode materials with uniform temperature distribution, high heating and cooling rates, high temperatures, and ultrafast reaction times. Li can be selectively leached through water leaching after CTS process with an efficiency of >90 %. Ni, Co, and Mn are recovered by dilute acid leaching with efficiencies >98 %. The CTS reduction strategy is feasible for various spent cathode materials, including NCM111, NCM523, NCM622, NCM811, LiCoO2, and LiMn2O4. The CTS process, with its low energy consumption and potential scale application, provides an efficient and environmentally friendly way for recovering spent lithium-ion batteries.  相似文献   

16.
《中国化学快报》2023,34(11):108228
Li2ZrCl6 (LZC) solid-state electrolytes (SSEs) have been recognized as a candidate halide SSEs for all-solid-state Li batteries (ASSLBs) with high energy density and safety due to its great compatibility with 4 V-class cathodes and low bill-of-material (BOM) cost. However, despite the benefits, the poor chemical/electrochemical stability of LZC against Li metal causes the deterioration of Li/LZC interface, which has a detrimental inhibition on Li+ transport in ASSLBs. Herein, we report a composite SSE combining by LZC and argyrodite buffer layer (Li6PS5Cl, LPSC) that prevent the unfavorable interaction between LZC and Li metal. The Li/LPSC-LZC-LPSC/Li symmetric cell stably cycles for over 1000 h at 0.3 mA/cm2 (0.15 mAh/cm2) and has a high critical current density (CCD) value of 2.1 mA/cm2 at 25 °C. Under high temperature (60 °C) which promotes the reaction between Li and LZC, symmetric cell fabricated with composite SSE also display stable cycling performance over 1200 h at 0.3 mAh/cm2. Especially, the Li/NCM ASSLBs fabricated with composite SSE exhibit a high initial coulombic efficiency, as well as superior cycling and rate performance. This simple and efficient strategy will be instrumental in the development of halide-based high-performance ASSLBs.  相似文献   

17.
Li-ion batteries with LiFePO4/C composites are difficult to be charged at low temperatures. In order to improve the low temperature performance of LiFePO4/C power batteries, the charge–discharge characteristics were studied at different temperatures, and a new charging mode under low temperature was proposed. In the new charging mode, the batteries were excited by current pulses with the charge rates between 0.75 C and 2 C, while the discharge rates between 3 and 4 C before the conventional charging (CC–CV). Results showed that the surface temperature of Li-ion battery ascended to 3 °C at the end of pulse cycling when the environment temperature was −10 °C. Comparing with the conventional charging, the whole charge time was cut by 36 min (23.4%) and the capacity was 7.1% more at the same discharge rate, respectively.  相似文献   

18.
Lithium batteries employing Li or silicon (Si) anodes hold promise for the next-generation energy storage systems. However, their cycling behavior encounters rapid capacity degradation due to the vulnerability of solid electrolyte interphases (SEIs). Though anion-derived SEIs mitigate this degradation, the unavoidable reduction of solvents introduces heterogeneity to SEIs, leading to fractures during cycling. Here, we elucidate how the reductive stability of solvents, dominated by the electrophilicity (EPT) and coordination ability (CDA), delineates the SEI formed on Li or Si anodes. Solvents exhibiting lower EPT and CDA demonstrate enhanced tolerance to reduction, resulting in inorganic-rich SEIs with homogeneity. Guided by these criteria, we synthesized three promising solvents tailored for Li or Si anodes. The decomposition of these solvents is dictated by their EPTs under similar solvation structures, imparting distinct characteristics to SEIs and impacting battery performance. The optimized electrolyte, 1 M lithium bis(fluorosulfonyl)imide (LiFSI) in N-Pyrrolidine-trifluoromethanesulfonamide (TFSPY), achieves 600 cycles of Si anodes with a capacity retention of 81 % (1910 mAh g−1). In anode-free Cu||LiNi0.5Co0.2Mn0.3O2 (NCM523) pouch cells, this electrolyte sustains over 100 cycles with an 82 % capacity retention. These findings illustrate that reducing solvent decomposition benefits SEI formation, offering valuable insights for the designing electrolytes in high-energy lithium batteries.  相似文献   

19.
Electrolyte engineering is crucial for the commercialization of lithium metal batteries. Here, lithium metal is stabilized in the highly reactive sulfolane-based electrolyte under low concentration (0.25 M) for the first time. Inorganic-polymer hybrid solid electrolyte interphase (SEI) with high ionic conductivity, low bonding with lithium and high flexibility enables dense chunky lithium deposition and high plating/stripping efficiency. Low concentration electrolyte (LCE) also enables excellent cycling stability of LiNi0.5Co0.2Mn0.3O2 (NCM523)/Li cells at 1 C (90.7 % retention after 500 cycles) and 0.3 C (83.3 % retention after 1000 cycles). With a low N/P ratio (≈2), the capacity retention for NCM523/Li cells can achieve 94.3 % after 100 cycles at 0.3 C. Exploring the LCE is of paramount significance because it provides more possibilities of the lithium salt selections, especially reviving some lithium salts that are excluded before due to their low solubility. More importantly, LCE has the significant advantage of commercialization due to its cost-effectiveness.  相似文献   

20.
All-solid-state polymer lithium-ion batteries are ideal choice for the next generation of rechargeable lithium-ion batteries due to their high energy, safety and flexibility. Among all polymer electrolytes, PEO-based polymer electrolytes have attracted extensive attention because they can dissolve various lithium salts. However, the ionic conductivity of pure PEO-based polymer electrolytes is limited due to high crystallinity and poor segment motion. An inorganic filler SiO2 nanospheres and a plasticizer Succinonitrile (SN) are introduced into the PEO matrix to improve the crystallization of PEO, promote the formation of amorphous region, and thus improve the movement of PEO chain segment. Herein, a PEO18−LiTFSI−5 %SiO2−5 %SN composite solid polymer electrolyte (CSPE) was prepared by solution-casting. The high ionic conductivity of the electrolyte was demonstrated at 60 °C up to 3.3×10−4 S cm−1. Meanwhile, the electrochemical performance of LiFePO4/CSPE/Li all-solid-state battery was tested, with discharge capacity of 157.5 mAh g−1 at 0.5 C, and capacity retention rate of 99 % after 100 cycles at 60 °C. This system provides a feasible strategy for the development of efficient all-solid-state lithium-ion batteries.  相似文献   

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