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Considered the promising anode material for next‐generation high‐energy lithium‐ion batteries, SiOx has been slow to commercialize due to its low initial Coulombic efficiency (ICE) and unstable solid electrolyte interface (SEI) layer, which leads to reduced full‐cell energy density, short cycling lives, and poor rate performance. Herein, a novel strategy is proposed to in situ construct an artificial hybrid SEI layer consisting of LiF and Li3Sb on a prelithiated SiOx anode via spontaneous chemical reaction with SbF3. In addition to the increasing ICE (94.5%), the preformed artificial SEI layer with long‐term cycle stability and enhanced Li+ transport capability enables a remarkable improvement in capacity retention and rate capability for modified SiOx. Furthermore, the full cell using Li(Ni0.8Co0.1Mn0.1)O2 and a pre‐treated anode exhibits high ICE (86.0%) and capacity retention (86.6%) after 100 cycles at 0.5 C. This study provides a fresh insight into how to obtain stable interface on a prelithiated SiOx anode for high energy and long lifespan lithium‐ion batteries. [ABSTRACT FROM AUTHOR]

Understanding the volume expansion behavior of Si anodes and their interaction with electrolyte environments is crucial for developing high-performance lithium-ion batteries (LIBs). This study utilizes a graphene liquid cell for in situ imaging to systematically investigate the volume expansion and etching behavior of Si anode nanoparticles in different electrolyte environments. Comparative experiments on Si@C core-shell nanoparticles assess their volume expansion dynamics. The findings reveal significant variation in the expansion rate of nano Si depending on the electrolyte environment, with chemical etching observed under specific conditions. Conversely, Si@C core-shell structures show mitigated expansion due to the confinement effect of the carbon matrix. Battery performance experiments validate these results, demonstrating the excellent cycling stability of Si@C anodes. Various coating agents are explored to optimize Si@C structures, with dopamine thin layer coating exhibiting the best cycling stability. This study offers fundamental insights into Si anode expansion, electrolyte effects, and carbon coating impacts, advancing LIB technology. [Display omitted] • Graphene liquid cell enables in situ imaging to study volume expansion and etching behavior of Si anode nanoparticles. • Si@C core-shell nanoparticles show reduced Si expansion due to the confinement effect of the carbon matrix. • Polydopamine coating on Si@C structures significantly enhances cycling stability and performance. • Si@PDA anode demonstrated stable capacity of 954 mAh g-1 and excellent rate capability after 500 cycles at 0.2 C. [ABSTRACT FROM AUTHOR]

High loading electrode design is beneficial to increase the energy density of lithium ion batteries. Two obstacles for the high loading electrode application should be removed, including the limitation on ion/electron transport within high loading electrode and the structure stability. Here, the electron conduction on LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathodes is enhanced with evenly and tightly Ketjen Black coating via high-speed dry mixing, while carbon nanotube is added to enhance the electron conduction between LiNi 0.8 Co 0.1 Mn 0.1 O 2 particles, thus to construct three-dimensional electron migration channel. In addition, the large amount of electrolyte adsorbed by porous Ketjen Black and carbon nanotube enhances the Li+ ion diffusivity in this network. As a result, LiNi 0.8 Co 0.1 Mn 0.1 O 2 electrode with only 1 % Ketjen Black and 3 % carbon nanotube can achieve both high electron/Li+ ion diffusivity and high parking density (2.2 g cm−3). A thick electrode with an areal mass loading of 20 mg cm−2 shows a high specific capacity of 111.2 mA h g−1 at 4 C and capacity retention rate of 98.2 % after 100 cycles at 2 C. • Electron/Li + ion mixed conduction network is constructed with porousKB and CNT. • High energy dry mixing is introduced to evenly and tightly coat KB on NCMcathode. • Electrochemical performance ofhigh loading electrodesis enhanced. [ABSTRACT FROM AUTHOR]

Conventional separators applied in lithium batteries face limitations like low porosity, poor electrolyte wettability, lower cation selectivity, and thermal instability, which impact battery performance and safety characteristics. Besides the challenge in separator design, transition metal ion migration from positive electrodes during cycling greatly accelerates capacity fading because of unrestricted diffusion of transition metal cation across the separator. This study explores an innovative strategy for the separator design by incorporating MXene (spraying MXene solution on both sides of the separator), a two-dimensional material, into electrospun Polyacrylonitrile/Polyetherimide membranes with the function of cation selection. Li+ can be accelerated, and its transference number increases along with the anion limitation in the MXene layer. Ni, Co, and Mn ion dissolution from the positive electrode is inhibited due to the cation selectivity of the MXene layer. Leveraging electrospinning advantages, the resultant membranes exhibit high porosity, excellent liquid absorption, mechanical strength, and superior thermal properties. Benefiting from MXene's layered structure and excellent adsorption ability, the membrane significantly inhibits the dissolution of transition metal ions while enabling smooth lithium deposition due to its cation selectivity. Eventually, the Li||NMC811 batteries deliver outstanding cyclic performance (91.3 % capacity retention after 200 cycles) and robust lithium dendrite suppression (800 h of stable cycling). Moreover, the MXene-modified membrane demonstrates exceptional electrolyte wettability, significantly improving ionic transference number (0.67) and conductivity (1.6 mS/cm). Modification of membrane surfaces with MXene offers insights into addressing transition metal ion migration from the positive electrode material perspective, providing a promising avenue for high-performance LIBs. [Display omitted] • Uniformly sized nanofiber membranes were obtained via electrospinning with uniform MXene composite. • MXene modified membrane exhibits cation selectivity: only Li ion transferred while transition metal ions retained. • The excellent interlayer spacing of MXene restricts lithium deposition in the vertical direction to inhibit dendrite growth. • Li.||NCM811 batteries exhibit a capacity retention rate of 91.3 % with deposition-stripping cycling for 600 h at 2 mA cm−2. [ABSTRACT FROM AUTHOR]

Nonflammable electrolytes are promising substitutes for the state-of-the-art carbonate-based electrolytes in order to directly enhance the safety characteristics of lithium ion batteries. Combination of trimethyl phosphate (TMP) and a fluorinated ether of 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (FEPE) is designed to formulate nonflammable electrolytes. The reformulated electrolytes of 1 mol/L LiPF6/TMP + FEPE (9:1, 8:2 and 7:3, w/w) are totally nonflammable. The FEPE solvent has higher oxidative stability and the FEPE-containing electrolytes have better separator wettability than the pure TMP electrolyte (1 mol/L LiPF6/TMP). The improved oxidative stability and separator wettability can enhance electrochemical stability of electrolyte on high-voltage cathode LiNi0.5Mn1.5O4. In Li4Ti5O12/LiNi0.5Mn1.5O4 cells, the FEPE-containing electrolyte exhibits the better cycling stability than the pure TMP electrolyte, and the solvent composed of TMP + FEPE (8:2) is the optimal ratio. The Li4Ti5O12/LiNi0.5Mn1.5O4 cell with the optimal electrolyte exhibits better rate capability because of the reduced polarization and improved oxidation stability. This work reveals the effect of fluorinated ethers on separator wettability of TMP-based nonflammable electrolytes and high-voltage applications. [ABSTRACT FROM AUTHOR]

A paper-supported inorganic composite (PIC) separator is prepared by spraying Al 2 O 3 particles onto both surfaces of a commercial paper substrate. The as-prepared PIC separator shows excellent thermal stability without any shrinkage at 130 °C for 30 min, superior wettability towards the electrolyte, with a contact angle of 0°, and high ionic conductivity compared with that of the conventional polyethylene (PE) separator. The graphite|LiCoO 2 full-cells with the PIC separator exhibit good cycling and rate performance. In the nail penetration tests, the pouch cell assembled with the PIC separator shows high safety characteristics. Given the advantages of the PIC separator, it is a good potential replacement for the polyolefin separators used in high-safety lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Separator wettability is vital to electrochemical performance of lithium metal batteries. This study demonstrates that the wettability of the polyolefin separator is enhanced by adding lithium bis(trifuoromethanesulfonyl)imide (LiTFSI) in the electrolyte and the good wettability has the positive impacts on the rate performance and lithium dendrite suppression of lithium metal batteries. Moreover, the underlying wetting mechanism of the LiTFSI has been investigated by the comparison with its cousin lithium bis(fluorosulfonyl)imide (LiFSI). It is revealed that perfluorinated alkyl (-CF 3 ) groups in TFSI - anions can greatly reduce the surface tension of the electrolyte, and thus favor the good wettability of the separator. The better separator wettability of 1 M LiTFSI/propylene carbonate (PC) than those of 1 M LiFSI/PC and 1 M LiPF 6 /PC contributes to the higher rate capability in Li||LiFePO 4 batteries. Introduction of the LiTFSI into the LiPF 6 -based electrolyte can obtain comparable separator wettability with the LiTFSI-based electrolyte. Owing to the greatly enhanced wettability of the separator, the electrolyte of 0.4 M LiPF 6 -0.6 M LiTFSI/PC as well as 1 M LiTFSI/PC has the positive effect on the lithium dendrite suppression in the lithium metal batteries. [ABSTRACT FROM AUTHOR]

Rechargeable lithium (Li) metal batteries with conventional LiPF 6 -carbonate electrolytes have been reported to fail quickly at charging current densities of about 1.0 mA cm −2 and above. In this work, we demonstrate the rapid charging capability of Li||LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) cells can be enabled by a dual-salt electrolyte of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium bis(oxalato)borate (LiBOB) in a carbonate solvent mixture. The cells using the LiTFSI-LiBOB dual-salt electrolyte significantly outperform those using the LiPF 6 electrolyte at high charging current densities. At the charging current density of 1.50 mA cm −2 , the Li||NCA cells with the dual-salt electrolyte can still deliver a discharge capacity of 131 mAh g −1 and a capacity retention of 80% after 100 cycles. The Li||NCA cells with the LiPF 6 electrolyte start to show fast capacity fading after the 30th cycle and only exhibit a low capacity of 25 mAh g −1 and a low retention of 15% after 100 cycles. The reasons for the good chargeability and cycling stability of the cells using the LiTFSI-LiBOB dual-salt electrolyte can be attributed to the good film-formation ability of the electrolyte on the Li metal anode and the highly conductive nature of the sulfur-rich interphase layer. [ABSTRACT FROM AUTHOR]

In this study, LiFePO/C is synthesized via a novel two-step method. The first step is the synthesis of nano-sized intermediate FePO by a modified sol-gel method. A fast and full combustion procedure is involved to remove carbon and control the size of the intermediate particles. The second step is to prepare LiFePO/C by combining solid-state reaction with controllable carbon coating. This two-step method is facile to prepare nano-sized LiFePO and easy to optimize the carbon content for surface coating. X-ray diffraction shows that the LiFePO/C composite possesses good crystallinity. Spherical morphology with a diameter of 30-150 nm is observed by scanning electron microscope and transmission electron microscope. Electrochemical measurements indicate that the LiFePO/C composite exhibits discharge capacities of 162, 144, 126, and 106 mAh g at 0.1, 1, 2, and 5C, respectively. No capacity fading is observed in 50 cycles. [ABSTRACT FROM AUTHOR]

Abstract: An Al2O3 inorganic separator is prepared by a double sintering process. The Al2O3 separator has a high porosity and good mechanical strength. After the liquid electrolyte is infiltrated, the separator exhibits quite high ionic conductivities, and even the conductivity reaches 0.78mScm−1 at −20°C. Furthermore, the inorganic separator has an advantage over the polymer separator in the electrolyte retention. The LiFePO4/graphite cell using the Al2O3 inorganic separator shows higher discharge capacity and rate capability, and better low-temperature performance than that using the commercial polymer separator, which indicates that the Al2O3 separator is very promising to be applied in the lithium-ion batteries. [Copyright &y& Elsevier]

Abstract: Li4Ti5O12/graphene composite was prepared by a facile sol–gel method. The lattice structure and morphology of the composite were investigated by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The electrochemical performances of the electrodes have been investigated compared with the pristine Li4Ti5O12 synthesized by a similar route. The Li4Ti5O12/graphene composite presents a higher capacity and better cycling performance than Li4Ti5O12 at the cutoff of 2.5–1.0V, especially at high current rate. The excellent electrochemical performance of Li4Ti5O12/graphene electrode could be attributed to the improvement of electronic conductivity from the graphene sheets. When discharged to 0V, the Li4Ti5O12/graphene composite exhibited a quite high capacity over 274mAhg−1 below 1.0V, which was quite beneficial for not only the high energy density but also the safety characteristic of lithium-ion batteries. [Copyright &y& Elsevier]

Abstract: Graphene/nanosized silicon composites were prepared and used for lithium battery anodes. Two types of graphene samples were used and their composites with nanosized silicon were prepared in different ways. In the first method, graphene oxide (GO) and nanosized silicon particles were homogeneously mixed in aqueous solution and then the dry samples were annealed at 500°C to give thermally reduced GO and nanosized silicon composites. In the second method, the graphene sample was prepared by fast heat treatment of expandable graphite at 1050°C and the graphene/nanosized silicon composites were then prepared by mechanical blending. In both cases, homogeneous composites were formed and the presence of graphene in the composites has been proved to effectively enhance the cycling stability of silicon anode in the lithium-ion batteries. The significant enhancement on cycling stability could be ascribed to the high conductivity of the graphene materials and absorption of volume changes of silicon by graphene sheets during the lithiation/delithiation process. In particular, the composites using thermally expanded graphite exhibited not only more excellent cycling performance, but also higher specific capacity of 2753mAh/g because the graphene sheets prepared by this method have fewer structural defects than thermally reduced GO. [Copyright &y& Elsevier]

Abstract: Niobium doped lithium titanate with the composition of Li4Ti4.95Nb0.05O12 has been prepared by a sol–gel method. X-ray diffraction (XRD) and scanning electron microscope (SEM) are employed to characterize the structure and morphology of Li4Ti4.95Nb0.05O12. The Li4Ti4.95Nb0.05O12 electrode presents a higher specific capacity and better cycling performance than the Li4Ti5O12 electrode prepared by the similar process. The Li4Ti4.95Nb0.05O12 exhibits an excellent rate capability with a reversible capacity of 135mAhg−1 at 10C, 127mAhg−1 at 20C and even 80mAhg−1 at 40C. Electrical resistance measurement and electrochemical impedance spectra (EIS) reveal that the Li4Ti4.95Nb0.05O12 exhibits a higher electronic conductivity and faster lithium-ion diffusivity than the Li4Ti5O12, which indicates that niobium doped lithium titanate (Li4Ti4.95Nb0.05O12) is promising as a high rate anode for the lithium-ion batteries. [Copyright &y& Elsevier]

Surface corrosion from electrolyte and reconstruction of layer‐structure LiCoO2 are the most important reasons for capacity decay and charging kinetics limitation. Spinel‐type material forms on the surface of LiCoO2 after cycling, which is more stable than the layer‐structure. To stabilize the surface and suppress the reconstruction, double layer structure Li1.6Mg1.6Sn2.8O8 matching LiCoO2 well is introduced to protect Mg‐doped LiCoO2 and restrain the structure change. With a simple surface coating of SnO2 and further high temperature treatment, Mg2+ in LiCoO2 and partly Li+ are extracted out and reacted with SnO2 to form double layer Li1.6Mg1.6Sn2.8O8. Meanwhile, Co3+ in pristine LiCoO2 is partly oxidized and electronic conductivity enhanced after surface modification. The Li1.6Mg1.6Sn2.8O8 coating efficiently stabilizes the surface structure of LiCoO2, with less structure change, less cracks appearing on the surface, and much better cycling performance. In addition, stable surface and higher electronic conductivity of LiCoO2 lead to better rate performance. [ABSTRACT FROM AUTHOR]

A thin inorganic composite membrane composed of 94 wt% Al 2 O 3 and 6 wt% styrene-butadiene rubber (SBR) polymer binder is prepared via an aqueous solution casting process. 1 wt% polyethylene glycol (PEG) is introduced into the casting suspension for the preparation of a 37 µm-thick inorganic composite separator. PEG plays a key role to enhance the stability of the casting suspension to separate the thin membrane from the substrate, and to increase the porosity of the membrane. The as-prepared Al 2 O 3 /SBR separator shows a superior thermal stability under 130 °C with no any shrinkage, higher electrolyte uptake/retention and ionic conductivity than the common polyethylene (PE) separator. In LiNi 1/3 Co 1/3 Mn 1/3 O 2 |graphite cells, the inorganic composite separator exhibits excellent cycling stability and good rate performance. [ABSTRACT FROM AUTHOR]

An organic lithium cyclophosphate named lithium 1, 3, 2-dioxaphosphinan-2-olate 2-oxide (LiDOP) was designed and synthesized as cathode electrolyte interface forming-film additive. It can undergo ring-opening polymerization during charging and form an organic–inorganic hybrid polymers on the cathode surface with alternately connected –LiPO 4 and –(CH 2) 3 –. The LiDOP-derived CEI film possesses high ionic conductivity, flexibility and mechanical strength. [Display omitted] • Designed and synthesized an air-stable cyclophosphate Li salt as electrolyte additive. • The synthesized Li salt can be preferentially oxidized and form an organic–inorganic hybrid polymer on the cathode surface with –LiPO 4 and –(CH 2) 3 – alternately connected. • The formed CEI film possess a higher ionic conductivity and mechanical strength than conventional organic or inorganic-based CEI film. • Being able to enhance the rate performance (5C) and long-term cycling performance under 4.8 V for high-voltage lithium-ion batteries. The structural stability and ionic conductivity of the cathode electrolyte interface (CEI) film at high voltages are crucial to the nickel-rich layered cathode in Li-ion batteries (LIBs). These characteristics are largely determined by electrolyte components. Herein, an air-stable organic cyclophosphate salt named lithium 1, 3, 2-dioxaphosphinan-2-olate-2-oxide (LiDOP) is designed and synthesized as a CEI forming additive. It preferentially oxidizes and undergoes opening-ring polymerization under charging to form an organic–inorganic hybrid polymers with –LiPO 4 segments and –(CH 2) 3 – alternately connected on the cathode surface. Such a structure endows CEI film with high ionic conductivity, flexibility and mechanical strength, which can ameliorate the structure phase transformation, suppress the transition metal ion dissolution and enhance the interfacial stability at high cut-off voltage. The electrolyte with 0.2 wt% LiDOP endows 4.3 V-charged Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 battery with 83.2 % capacity retention after 200 cycles at 5C rate. The graphite||NCM811 pouch cell shows a capacity retention of 85.6 % after 150 cycles under a 4.5 V voltage, while the cell without LiDOP shows only 23.5 %. Our work demonstrates the effectiveness of covalently coupled P-O-Li compounds as CEI film in stabilizing the interface, which provides a guidance for the electrolyte design in high-voltage LIBs. [ABSTRACT FROM AUTHOR]

Abstract: Fe3O4–graphene nanocomposite was prepared by a gas/liquid interface reaction. The structure and morphology of the Fe3O4–graphene nanocomposite were characterized by X-ray diffraction, scanning electron microscopy and high-resolution transmission electron microscopy. The electrochemical performances were evaluated in coin-type cells. Electrochemical tests show that the Fe3O4–22.7wt.% graphene nanocomposite exhibits much higher capacity retention with a large reversible specific capacity of 1048mAhg−1 (99% of the initial reversible specific capacity) at the 90th cycle in comparison with that of the bare Fe3O4 nanoparticles (only 226mAhg−1 at the 34th cycle). The enhanced cycling performance can be attributed to the facts that the graphene sheets distributed between the Fe3O4 nanoparticles can prevent the aggregation of the Fe3O4 nanoparticles, and the Fe3O4–graphene nanocomposite can provide buffering spaces against the volume changes of Fe3O4 nanoparticles during electrochemical cycling. [ABSTRACT FROM AUTHOR]

Along with the cathode, anode, and liquid electrolyte in lithium-based secondary batteries, the separator is a crucial element for guaranteeing battery safety. However, conventional polyolefin separators suffer from inherent drawbacks such as inadequate compatibility with electrolytes and limited thermal stability. These limitations can lead to issues like high-temperature shrinkage, melting, and even combustion. Moreover, the vulnerability of separators toward lithium dendrite penetration exacerbates safety concerns associated with lithium-ion batteries. Hence, the design of high safety separators is currently a focus and challenge. In this study, we develop a multifunctional polymer-coupled nanofiber membrane by an electrospinning method that addresses the above issue as a separator of lithium metal battery. The nanofiber coating contains carbonyl oxygen, pyrrole nitrogen, and cross-linked networks with tertiary amine groups. These components effectively neutralize acidic compounds generated during the liquid electrolyte side reaction. X-ray micro-computed tomography analysis verifies the exceptional structural stability of the new separator, maintaining its 3D skeleton even after 2000 h of cycling. The nanofiber separator in a full Li||NCM811 cell achieves a high specific capacity of 136.6 mA h g−1 at 0.9 A g−1 and displays outstanding long-cycle stability over 500 cycles with a capacity retention of 88.5%. [Display omitted] • The membrane contains cross-linked networks featuring tertiary amine groups. • Highly porous and stable separator morphology is quantified via CT tomography. • The battery using the separator has a high capacity retention (88.5%) after 500 cycles. [ABSTRACT FROM AUTHOR]

In this work, tris(2-(thiophen-2-yl) ethyl) phosphate is designed, synthesized and applied as a functional electrolyte additive for lithium ion batteries with high-voltage LiCoO 2 cathode. The tris(2-(thiophen-2-yl) ethyl) phosphate contains both of thiophen group and phosphorus element. The thiophen group forms a thinner electron conductive cathode electrolyte interphase to increase the thermal stability of LiCoO 2 to de-active the catalytic and oxidative sites. In addition, the phosphorus element enhances the interfacial lithium ion conductivities by forming LiP x O y F z. Therefore, the thiophen group and phosphorus element in tris(2-(thiophen-2-yl) ethyl) phosphate work synergistically to optimize the electronic and ionic conductivity of cathode electrolyte interphase in high-voltage lithium ion batteries. As a result, when the batteries are cycled in the electrolyte with 0.1 wt% tris(2-(thiophen-2-yl) ethyl) phosphate, the Li//LiCoO 2 half cells perform high thermal stability and deliver an excellent rate capability of 140 mAh g−1 at 5 C, and the graphite//LiCoO 2 full cells present a significantly improved discharge capacity and stability of 139.9 mAh g−1 at 130 cycles with a high capacity retention of 90.72%. Image 1 • Tris(2-(thiophen-2-yl) ethyl) phosphate (TTEP) is designed and synthesized. • TTEP contains both of thiophen group and phosphorus (P) element. • TTEP synergistically enhances electronic and ionic conductivities of CEI. • TTEP helps the batteries to perform excellent electrochemical performances. [ABSTRACT FROM AUTHOR]

Abstract A Sb 2 O 3 -modified poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) fibrous membrane is prepared via a sequential electrospinning technique and used as a safe separator for lithium-ion batteries. A small amount of 2% Sb 2 O 3 nanoparticles can effectively improve mechanical strength of the PVDF-CTFE membrane. Besides, the Sb 2 O 3 modified PVDF-CTFE electrospun fibrous membrane exhibited synergistic flame retardancy as well as outstanding thermal stability without shrinkage at 160 °C for 2 h. Furthermore, the Sb 2 O 3 -modified PVDF-CTFE membrane as a composite separator possessed superior wettability toward nonaqueous electrolyte, higher ionic conductivity, lower interfacial resistance and well electrochemical stability compared to the commonly used polyethylene separator. Therefore, the Li||LiFePO 4 cell using this type of composite separator exhibits excellent cycling stability and superior rate capability. These results suggest that the Sb 2 O 3 -modified PVDF-CTFE electrospun fibrous membrane is attractive for high-performance and high-safety lithium-ion batteries. Graphical abstract fx1 Highlights • Electrospun PVDF-CTFE fibrous separators lead to outstanding thermal stability. • Sb 2 O 3 modified PVDF-CTFE separator exhibits enhanced mechanical strength. • Synergistic flame retardancy by Sb 2 O 3 and F, Cl in PVDF-CTFE enhances safety. [ABSTRACT FROM AUTHOR]

The practical application of lithium (Li) metal anode in rechargeable Li batteries is hindered by both the growth of Li dendrites and the low Coulombic efficiency (CE) during repeated charge/discharge cycles. Recently, we have discovered that CsPF 6 as an electrolyte additive can significantly suppress Li dendrite growth and lead to highly compacted and well aligned Li nanorod structures during Li deposition on copper substrates. In this paper, the effect of CsPF 6 additive on the performance of rechargeable Li metal batteries with lithium iron phosphate (LFP) cathode is further studied. Li|LFP coin cells with CsPF 6 additive in electrolytes show well protected Li anode surface, decreased resistance, enhanced rate capability and extended cycling stability. In Li|LFP cells, the electrolyte with CsPF 6 additive shows excellent long-term cycling stability (at least 500 cycles) at a charge current density of 0.5 mA cm −2 without internal short circuit. At high charge current densities, the effect of CsPF 6 additive becomes less significant. Future work needs to be done to protect Li metal anode, especially at high charge current densities and for long cycle life. [ABSTRACT FROM AUTHOR]

SiO x is considered to be a promising anode material for lithium-ion batteries (LIBs) due to the high lithium storage capacity. However, the large initial irreversible capacity loss and intensive volume change during cycling hinder its commercial applications. Prelithiation is an effective and convenient strategy to improve the initial Coulombic efficiency (ICE) of SiO x , while incomplete and unstable SEI on the prelithiated anode still results in rapid capacity decay. Herein, through the synergy effect of chemical pre-lithiation process and fluoroethylene carbonate reduction, a compact and stable LiF-rich SEI layer is in-situ formed on the surface of prelithiated SiO x anode. The modified SiO x anode exhibits a high ICE of 90.7% with good cycling performance. When paired with the commercial LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) cathode, the assemble pre-Li-SiO x /C||NCM622 full cell exhibit a high ICE of 85.7% and stable cycling stability. This work provides a new insight in constructing favorable SEI in pre-lithiation process. [Display omitted] [ABSTRACT FROM AUTHOR]

A series of composite gel polymer electrolytes (GPEs) based on poly (vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP), 1-ethtyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMIM][TFSI]), lithium bis(trifluoromethane) sulfonimide (LiTFSI) and covalent linked 2,2''-(ethylenedioxy) bis (ethylamine) to reduced graphene oxide (rGO-PEG-NH 2) have been successfully prepared by solution casting method. With the increase of [EMIM][TFSI] and rGO-PEG-NH 2 content, the crystallinity of the GPE decreased, and the thermal decomposition temperature increased significantly. A high-speed lithium ion transport network was formed in the 3P5E2LG-10 GPE, with rGO as the connection site and PEG as the bridge. 3P5E2LG-10 GPE exhibited a conductivity of 2.1 × 10−3 S cm−1 at 30 °C, a lithium ion transference number of 0.45, and a electrochemical window of 5.0 V. The 3P5E2LG-10 based cell exhibited more than 99% columbic efficiency and the initial discharge capacity reached the maximum of 163.7 mAh/g, and capacity retention was about 88% after 80 cycles at 0.1C. 3P5E2LG-10 GPE will have great potential for lithium ion battery with high safety and long cycle life. Image 1 • [EMIM][TFSI] and rGO-PEG-NH 2 decrease the crystallinity of PVDF-HFP and promote transmission of lithium ion. • 3P5E2LG-10 exhibits 2.1 × 10−3 S cm−1, a lithium ion transference number of 0.45, and a electrochemical window of 5.0 V. • The electrolyte has excellent cycle performance and good inhibitory effect on the growth of lithium dendrites. [ABSTRACT FROM AUTHOR]