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The semiconductive layer located between the core and insulation layer of a high-voltage DC (HVDC) cable can inhibit the accumulation of space charge in the insulation layer. This helps increasing the electric field inside the cable, thus improving the stress distribution of the electric field on the inner and outer surfaces of the insulation layer and the electrical strength of the cable. An inevitable positive temperature coefficient effect (PTC) in the semiconductor layer leads to aging failure of the insulation layer. To improve this phenomenon, the semiconductive shielding layer was modified for suppressing its PTC effect and reducing the space charge injection into the insulation layer. Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) was prepared via a solid-phase reaction and added to a composite consisting of carbon black (CB), ethylene vinyl acetate copolymer (EVA), and low-density polyethylene (LDPE). Resistivity, thermally stimulated depolarization current (TSDC), and pulsed electroacoustic (PEA) measurements were performed on the modified sample. The results showed that when the LATP content was 4 wt%, the modification effect of the semiconductive shielding layer was most effective, the PTC effect was reduced by 11%, and the space charge injection into the insulating layer was improved significantly. [ABSTRACT FROM AUTHOR]

[Display omitted] InCl 3 @Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 -F (InCl 3 @LATP-F) solid electrolyte powders are designed and fabricated by coating a uniform InCl 3 layer on the surface of F--doped Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP-F) solid powders via a feasible wet-chemical technique. The assembled Li/InCl 3 @LATP-F/Li cell can undergo longer cycles of 2500 h at 0.4 mA cm−2 without obvious increases in the overvoltage compared to 1837 h for the Li/LATP-F/Li cell, and the interfacial resistance demonstrates a sharp decrease from 3428 to 436 Ω for the Li/InCl 3 @LATP-F/Li cell during the first 500 h. Importantly, the assembled LiCoO 2 /InCl 3 @LATP-F/Li cell delivers a high discharge specific capacity of 126.4 mAh g−1 with a 95.42% capacity retention ratio after 100 cycles at 0.5 C , and the value easily returns to 112.9 mAh g−1 when the current density is abruptly set back to 0.1 C after different rate cycles. These improved results can be mainly attributed to the fact that the InCl 3 layer with a lithiophilic nature can react with lithium metal to form a Li-In alloy, which can guarantee homogeneous lithium ion flux to avoid the accumulation of ions/electrons across the interface and suppress the growth of lithium dendrites. Moreover, the InCl 3 layer can prevent direct contact of the LATP-F solid electrolyte and lithium metal to effectively alleviate the reduction reaction of Ti4+ and preserve the structural stability of the composite electrolyte. Therefore, this work may provide an effective strategy to engineer and regulate the interfacial stability between LATP solid electrolytes and lithium metal anodes for LATP-type solid-state lithium batteries. [ABSTRACT FROM AUTHOR]

The poor contact and side reactions between Li1.3Al0.3Ti1.7(PO4)3 (LATP) and lithium (Li) anode cause uneven Li plating and high interfacial impendence, which greatly hinder the practical application of LATP in high‐energy density solid‐state Li metal batteries. In this work, a multifunctional ferroelectric BaTiO3 (BTO)/poly(vinylidene fluoride‐co‐trifluoroethylene‐co‐chlorotrifluoroethylene) (P[VDF‐TrFE‐CTFE]) composite interlayer (B‐TERB) is constructed between LATP and Li metal anode, which not only suppresses the Li dendrite growth, but also improves the interfacial stability and maintains the intimate interfacial contact to significantly decrease the interfacial resistance by two orders of magnitude. The B‐TERB interlayer generates a uniform electric field to induce a uniform and lateral Li deposition, and therefore avoids the side reactions between Li metal and LATP achieving excellent interface stability. As a result, the Li/LATP@B‐TERB/Li symmetrical batteries can stably cycle for 1800 h at 0.2 mA cm−2 and 1000 h at 0.5 mA cm−2. The solid‐state LiFePO4/LATP@B‐TERB/Li full batteries also exhibit excellent cycle performance for 250 cycles at 0.5 C and room temperature. This work proposes a novel strategy to design multifunctional ferroelectric interlayer between ceramic electrolytes and Li metal to enable stable room‐temperature cycling performance. [ABSTRACT FROM AUTHOR]

At present, LiNi1/3Co1/3Mn1/3O2 (NCM) is a widely used material in the commercial market due to the easy control of the preparation process and usage environment. However, its capacity keeps fading when the cut-off voltage increases. In this research, an Li1.3Al0.3Ti1.7(PO4)3 (LATP) coating method is proposed to improve the cycle performance of LiNi1/3Co1/3Mn1/3O2 at a high cut-off voltage of 4.6 V. The battery prepared with LATP-modified NCM exhibits an increased discharge capacity retention of 92.37% after 100 cycles at 0.2C (1C = 200 mA g−1), while the bare NCM only presents 64.28%. Our results indicate that LATP-surface coating might be a useful method to increase the cycle stability of NCM and other high-capacity cathode materials. [ABSTRACT FROM AUTHOR]

Uneven lithium deposition and uncontrollable dendrite growth limit the development and progress of lithium-metal batteries (LMBs). Here, we developed an appropriate strategy to prevent the damage of Li dendrites by introducing inorganic oxide solid electrolyte layers (Li1.3Al0.3Ti1.7(PO4)3, LATP) on both sides of a polypropylene separator (PP). The inorganic coating layers, which comprise close-packed LATP solid electrolyte particles, afford a firm and uniform microstructure for the hybrid separator. At a current density (0.25 mA cm−2), the lithium symmetric batteries composed of the LATP/PP separator exhibit a long cycle life of over 1600 h in the 1 M LiTFSI-DOL/DME electrolyte. Furthermore, the LiFePO4||LATP/PP||Li cell presents a prominent performance and delivers an average charge capacity of 151 mAh g−1 at 1 C. This can be attributed to the unique characteristics of the LATP/PP separator, as it not only has outstanding mechanical strength and thermal stability, but also possesses high ionic conductivity, which effectively enhances the rate capacity to improve the safety of LMBs. LATP/PP separator is prepared by the coating method, and the Li symmetric batteries can cycle more than 1600 h in the 1 M LiTFSI-DOL/DME, which show an outstanding electrochemical performance. [ABSTRACT FROM AUTHOR]

The Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte powders doped with LiF are successfully synthesized by spray-drying and calcination methods, and the corresponding physicochemical properties are investigated using X-ray diffraction, a field emission-scanning electron microscope, and an X-ray photoelectron spectroscope. The results show that the LiF-doped LATP (LATP-0.15) solid electrolyte presents excellent performance compared with the pure LATP solid electrolyte when the weight ratio of LiF vs. LATP maintains at 0.15, in which the LATP-0.15 solid electrolyte possesses a higher compacted density of 2.887 g cm−2 and a higher ionic conductivity at room temperature of 1.767 × 10–4 S cm−1 with lower activation energy of 0.276 eV. Furthermore, the assembled LiCoO2/LATP-0.15/Li coin cell delivers a relatively high discharge specific capacity of 136.7 mAh g−1 at 0.1 C after only five active cycles and maintains up to 97.77% of capacity retention ratio after 290 cycles. Those results indicate that the as-prepared LATP-0.15 solid electrolyte may be employed to be a potential candidate in the future all-solid-state lithium-ion batteries. [ABSTRACT FROM AUTHOR]

To enhance the ionic conductivity and electrochemical stability of Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolytes, different contents of indium doping Li1.3Al0.3InxTi1.7-x(PO4)3 (LAITP) solid electrolyte powders are successfully synthesized by spray-drying and calcination processes. The characteristic results confirmed by X-ray diffraction, Fourier transform infrared spectrometer, and field emission scanning electron microscope show that the LAITP-0.12 solid electrolyte exhibits a uniform cube-like morphology, an excellent crystallinity, as well as a high compacted density of 2.239 g cm−3 compared to the pure LATP solid electrolyte when the content of indium doping is up to 12 wt. % vs. the pure LATP powders in the terms of the molar ratio. Moreover, the LAITP-0.12 solid electrolyte presents a high ionic conductivity of 1.779 × 10–4 S cm−1 at 30 ºC. The assembled Li/LAITP-0.12/Li symmetric cell can present excellent lithium platting/striping cycle performance for 500 h. Furthermore, the all-solid-state cell assembled with the LAITP-0.12 solid electrolyte shows extremely superior rate performance compared to other cells and delivers a high discharge specific capacity of 149.9 mAh g−1 at 30 ºC at 0.1 C. The surface and the characteristic diffraction peak of the disassembled LAITP-0.12 solid electrolytes exhibits dense cube-likes morphology and no distinct difference after cycles, respectively. Those results suggest that the effective In ion doping strategy may promote the development of the solid electrolytes for all-solid-state lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) is one of the most promising inorganic solid electrolytes, it combines together good electrochemical stability with high ionic conductivity. Its properties are strongly dependent on the consolidation route and the relevant literature confirms the beneficial role of rapid heating. Therefore, the recently emerged Ultrafast High-temperature Sintering (UHS) was selected to prevent undesired Li loss during processing. UHS densified LATP up a relative density of 90.2% within 100s while achieving a ionic conductivity as high as 4.7 × 10−4 S/cm at 25 °C. The rapid UHS heating (≈1500 °C/min) justified the increased density and slightly improved ionic conductivity of 4.67 × 10−4 S/cm if compared to counterparts (i.e., 85.4% and 3.9 × 10−4 S/cm) produced using conventional sintering at 900 °C with a dwell time of 6 h. Additionally, the UHSed electrolyte resulted in a 20% increase in grain boundary conductivity compared to conventionally sintered bulks. We identified a narrow processing window (discharge duration of 100 s and current of 20 A) suitable for producing dense and decomposition free LATP electrolytes. [ABSTRACT FROM AUTHOR]

A simple and effective method was developed and used to improve the conductivity and density of Li1.3Al0.3Ti1.7(PO4)3 solid–state electrolyte. The raw powders were synthesized through two different methods to expand the particle size distribution, which could improve the sintered density and the grain boundary connection of the of LATP electrolyte. Through this method, the relative density of the electrolyte made of mixed powders can reach to 97% compared with the 92% and 95% for electrolyte made of single solid-state reaction powder and sol-gel reaction powder, respectively. The conductivity test shows that this electrolyte has high total ion conductivity of 5.23 × 10−4 S cm−1 at room temperature with the grain boundary conductivity of 6.11 × 10−4 S cm−1. With the merits of high density and ion conductivity, this solid-state electrolyte shows good rate capability and cycle performance in aqueous lithium-oxygen batteries. [ABSTRACT FROM AUTHOR]

In this study, a NASICON-structured Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) powder is prepared by hydrothermal methods followed by calcination, cold pressing and post-sintering processes. The white, solid product is characterized thoroughly using powder X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) equipped with Energy Dispersive X-ray Spectroscopy (EDS). The conductivity of the material is measured by a impedance spectroscopy as a function of temperature. Initially, hydrothermal synthesis yields a material isostructural with the orthorhombic oxyphosphate, LiTiOPO 4. EDS analysis shows that the distribution of aluminum throughout this material is uniform. A systematic study is then performed to investigate how altering the sintering parameters (such as powder pre-sintering temperature and pellet sintering temperature) affect the formation of LATP. The structure is determined by Rietveld refinement against XRD data and the effects of sintering temperature on porosity, microstructure and electrical conductivity were resolved. The experimental results show that the optimum pre-sintering and sintering temperatures of LATP powders and pellets respectively are 900 °C and 1100 °C. These conditions produce materials with the highest density (99.07% of theoretical), superior conductivity (grain-, grain boundary- and total lithium-ion conductivities of 6.57 × 10−4, 4.59 × 10−4 and 2.70 × 10−4 S cm−1, respectively) and with an activation energy for Li motion of 0.17 eV. [ABSTRACT FROM AUTHOR]

Li1.3Al0.3Ti1.7(PO4)3 (LATP) has become the focus of research because of its high ionic conductivity, high oxidation voltage, and low air sensitivity. However, Ti4+ is easily reduced by Li metal. In this paper, amorphous Li1.5Al0.5Ge1.5(PO4)3 (a-LAGP) is introduced as an interface modification layer, because LAGP has the small electrochemical potential difference and Ge4+ is more difficult to be reduced by Li. Radio frequency sputtering (RF sputtering) is adopted to modify the a-LAGP thickness less than 100 nm. Compared with crystalline LAGP layer, a-LAGP has a better effect on improving the interface stability of LATP and Li. With the a-LAGP film, the Li/a-LAGP/LATP/a-LAGP/Li symmetrical cell is still stable after 100 cycles with the over potential changing from 1 V to 3 V. The probable mechanism of the good stability between a-LAGP and Li are discussed. [ABSTRACT FROM AUTHOR]

The lithium-ion conductor Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) is prepared by a solid-state method using nano-grass-like AlOOH as the Al source. The nano AlOOH precursor, obtained by a hydrothermal method, makes it easier for Al atoms to replace Ti atoms in the LiTi 2 (PO 4) 3 structure during the solid-state reaction process, which creates a large amount of lithium vacancies and lithium gaps, leading to the easier migration of Li+ ions in the obtained LATP conductor. Moreover, the as-prepared LATP has high crystallinity and high relative density (96.06%), which are beneficial for reducing the grain boundary resistance as well as improving the total ion conductivity. The influences of sintering temperature and holding time on the ionic conductivity and morphology of the LATP conductor are also discussed systematically. The total ion conductivity of LATP reaches to as high as 3.44 × 10-4 S cm-1 when the samples are sintered at 950 °C for 6 h. This work provides a new method for the preparation of LATP with high ion conductivity, which is of great significance for all-solid-state lithium-ion battery application. [ABSTRACT FROM AUTHOR]

NASICON-type solid electrolyte powders Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) are synthesized by spray-drying and assisted sintering processes. The effects of different pH values of the spray-dried precursor solution on the crystallinity, morphology, ionic conductivity, compaction density and cycling stability of the LATP solid electrolyte sheets are investigated. The LATP-6.0 solid electrolyte sheets present the most perfect microstructure with a compaction density of 2.968 g cm−1 and the highest ionic conductivity of 1.182 E−4 S cm−1 with an activation energy of 0.273 eV at room temperature when the pH value of the precursor solution is adjusted to 6.0. Additionally, the assembled LiCoO 2 /LATP-6.0/Li all-solid-state coin cell delivers commendable cycling stability with a high discharge specific capacity of 150.5 mAh g−1 at 0.1 C after five activation cycles and retains a specific capacity retention rate of 94.28% after 300 cycles with various current densities at room temperature. Moreover, the LATP-6.0 solid electrolyte sheets maintain an intact morphology and uniformly-distributed elements composition after cycling. Based on these excellent results, the use of the LATP-6.0 sheets as solid electrolytes in high-performance all-solid-state lithium-ion batteries is a promising strategy. [ABSTRACT FROM AUTHOR]

• Effect of Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) particle size in composite cathodes was studied. • Smaller LATP particles promote Li+ pathways formation in a composite cathode. • Comprehensive analysis results provide unique insights into the reaction mechanism. Solid electrolytes (SEs) are key materials for all-solid-state lithium-ion batteries (ASSLBs), and are being studied for various applications. Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP), a NASICON-type SE, is noteworthy due to its wide voltage range for cathode operation and economic feasibility. However, fabricating well-contacted interparticle interfaces in composite cathodes using LATP is challenging because of its high grain-boundary resistance. To address this issue, we investigated the correlation between lithium-ion transport in composite cathodes and the particle size of LATP. We successfully synthesized two LATPs with different size distributions and prepared composite cathodes. Performance evaluation and various advanced analyses of composite cathodes were conducted, the results revealed that LATP with a smaller particle-size distribution formed more a uniform Li+ transfer network in the composite cathode than the larger particles, which contributed to the stable and fast electrochemical characteristics of the ASSLB. Additionally, we also observed real-time structural changes during electrochemical reactions in composite cathodes through in situ X-ray diffraction analysis. The results of our comprehensive analysis are expected to provide valuable insights into the reaction mechanisms of LATP-based ASSLBs, as they have not been extensively explored before. [ABSTRACT FROM AUTHOR]

Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) solid electrolyte has caused great attention because of its low cost, high ionic conductivity, and superior air stability. In this work, high quality LATP ceramic electrolyte membranes are fabricated by an aqueous tape casting technique in the air, in contrast to traditional fabrication methods that are usually inefficient and noncontinuous, this technique provides an environment-friendly, scalable, continuous fabrication route for mass production of ceramic electrolyte membranes. The as-prepared LATP ceramic membrane with a relative density of 95.6 % shows a total Li ionic conductivity of 3.8 × 10−4 S cm−1. Simply coated with a flexible polymer electrolyte film on the surface of the LATP ceramic membrane, the solid-solid interfacial polarization between the LATP ceramic membrane and the electrodes can be well controlled under a reasonable level, leading to excellent battery performance. Discharge capacities of 160.6, 157.6, 151.2, 138.9 and 123.9 mAh g−1 at 0.05, 0.1, 0.2, 0.5 and 1 C rates are achieved, respectively. This study demonstrates a promising strategy for commercializing all-solid-state batteries with a cost-effective and scalable manufacturing technique. [Display omitted] • High quality LATP electrolyte membrane is fabricated by aqueous tape casting. • Interfacial polarization between LATP membrane and electrodes is well controlled. • Superior rate capability of LATP based all solid-state battery is achieved. [ABSTRACT FROM AUTHOR]

Monodispersed spherical Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) precursor particles are prepared by hydrolysis-complexation combined with spray-drying processes, and the desirable targeted LATP-900 particles are obtained after being calcinated at 900 °C in air confirmed by thermogravimetry-differential scanning calorimetry and X-ray diffraction analyses. The high compacted density of the particles with normal size distribution can be conductive to collecting the compacted LATP pellets, which can reach as high as 1.608 × 10−4 S cm−1 of ionic conductivity at 30 °C. The assembled LiCoO 2 /LATP-900/Li cell can stably deliver 138.2 mAh g−1 of discharge specific capacity after only four cycles and quickly recover to 132.3 mAh g−1 after 80 cycles when the current is set back to 0.1 C with nearly 100% coulombic efficiency, which suggests that the LATP-900 pellet can become a promising candidate for the high performance solid lithium ion batteries. [ABSTRACT FROM AUTHOR]

Abstract Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 is regarded as one of the most promising solid electrolytes for all solid state lithium ion batteries (ASSLIBS). However, its grain boundary conductivity is still low, which reduces the total conductivity of electrolyte. In this work, in order to further improve the electrical conductivity of Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 , a series of Y doped Li 1.3 Al 0.3-x Y x Ti 1.7 (PO 4) 3 (x = 0, 0.025, 0.05, 0.075 and 0.15) solid electrolytes were synthesized using a modified solid state method. Effects of Y doping content on morphology, phase and electrical conductivity of Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 electrolyte materials were systematically investigated. All synthetic electrolyte powders show Nasicon-like structure, well-shaped polyhedral morphology as well as good crystallinity. Y dopant content has a great influence on electrochemical properties of electrolytes. The high total conductivity of 7.8 × 10−4 S/cm at room temperature and a low activation energy of 0.17 eV is obtained for the electrolyte with the Y doping content of 0.075 due to the increasing of grain boundary conductivity, and its electrical conductivity is about 2 times larger than that of the undoped electrolyte. The excellent electrochemical performance is mainly attributed to high electrolyte density which results from the good sintering property of electrolyte materials as well as the existence of YPO 4 phase at grain boundaries. Additionally, this electrolyte has a negligible electronic conductivity. These results suggest that Y doped Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 can be used as an alternative solid electrolyte for all solid state lithium ion batteries. Highlights • Nasicon-type Y doped LATP materials were prepared by a modified solid state method. • The optimum conductivity was obtained for the sample with Y doping content of 0.075. • The highest electrical conductivity at room temperature is 7.8 × 10−4 S/cm. • The Y doped LATP electrolyte has a negligible electronic conductivity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon–Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) is formed as a conductive coating on LiFePO 4. • Li-ion insertion/extraction into/from LiFePO 4 is regulated and facilitated by LATP. • Voltage plateaus of LiFePO 4 are extended with carbon–LATP coating. • LATP provides additional charge and discharge capacities. A stable and conductive interface is essential in improving the performance of cathode materials in Li-ion batteries by reducing interfacial resistances and balancing the charge transfer, especially at high current rates. In this study, we design a hybrid conductive coating layer consisting of carbon (C) and Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) solid electrolyte on olivine LiFePO 4 (LFP) cathode material (LFP@C_LATP) to utilize the advantage of each coating component. Carbon is generally required to improve conductivity and protect LFP particles from undesirable side reactions at the electrode/electrolyte interface. At the same time, LATP is electrochemically active and exhibits superior Li-ion conductivity to LFP. Notably, our experimental results reveal that the coating layer can provide a buffer zone on the LFP particle surface to regulate Li-ion insertion/extraction, extend voltage plateaus, and contribute an extra capacity to the cathode material. The electrochemical performances of LFP@C_LATP, therefore, are significantly improved. As a result, the LFP@C_LATP cathode can deliver a discharge capacity of 164.5 mAh g−1 at 0.1 C. Particularly, it can be electrochemically active at an extremely high current rate, up to 60.0 C, after consecutively cycling for a number of cycles. This hybrid coating strategy is promising for developing high energy, high rate, and fast charge cathode materials. [ABSTRACT FROM AUTHOR]

Lithium Aluminum Titanium Phosphate (LATP) solid electrolyte has many advantages such as high ionic conductivity, good air stability, and low raw material cost, which has great potential for industrial development. However, the existing preparation process still can not meet the needs of industrialization well. We propose a novel simple solid-liquid mixing process to prepare LATP. By optimizing the reactants and adopting the "vacuum self-mixing" process, in the case of removing the mixing step, a high-performance LATP solid electrolyte with high purity is also obtained, the total ionic conductivity of the which at room temperature is as high as 1.7 ​mS/cm, the bulk conductivity is as high as 7.2 ​mS/cm, both reaching the highest value in published literature, the obtained sheet density is also as high as 99.4%. The process also avoids the problems of material sticking to the pot and low sintering yield in the traditional sintering process, which will provide a more convenient technological route for the industrialization of LATP solid electrolyte. The introduction of highly active raw materials not only eliminates the mixing step, but also the conductivity of the obtained LATP electrolyte reaches the highest value since reports. [Display omitted] • A novel method was used to prepare a high-purity LATP solid electrolyte. • High-purity LATP phase was still obtained under the non-mixing process. • The bulk ionic conductivity at room temperature reached 7.2 ​mS/cm. • The total ion conductivity at room temperature reached 1.7 ​mS/cm. • The ionic conductivity have reached the highest value reported in public. [ABSTRACT FROM AUTHOR]

Solid-state lithium metal batteries have excellent safety and energy density features compared to traditional lithium-ion batteries. However, they also suffer from large interface resistance and unstable contact with lithium metal resulting in a low rate and short cycle performance. Here, we utilize liquid electrolyte (LE) drips at the Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP)/electrode interface to form a solid–liquid hybrid electrolyte and reduce the interface impedance. In addition, the resulting solid–liquid electrolyte interface (SLEI) can prevent the reduction of LATP by lithium. Li/Li symmetric batteries exhibit excellent cycle stability of 500 h at 0.2 mA cm−1 when the volume ratio of liquid electrolyte to solid electrolyte LATP is 15% (SE-15% LE). The LiFePO 4 /SE-15%LE/Li battery system exhibit a high discharge capacity (151 mAh g−1) at 0.1 C and an excellent capacity retention rate (96.5% after 100 cycles at 25 °C). Moreover, the NCM622/SE-15% LE/Li battery system delivers an ultrahigh specific capacity of 184.3 mAh g−1 at 0.1 C. Overall, this study compares and explains the performance of the two cathode material systems. [Display omitted] • The LiFePO 4 system battery delivers excellent electrochemical performances. • The NCM622/SE-15%LE/Li battery system delivers 184.3 mAh g−1 at 0.1 C. • Compare and analyze the electrochemical performance of LFP and NCM622 system. • Analyze the reasons for the capacity fade of the NCM622 system. [ABSTRACT FROM AUTHOR]

The currently studied materials considered as potential candidates to be solid electrolytes for Li-ion batteries usually suffer from low total ionic conductivity. One of them, the NASICON-type ceramic of the chemical formula Li1.3Al0.3Ti1.7(PO4)3, seems to be an appropriate material for the modification of its electrical properties due to its high bulk ionic conductivity of the order of 10−3 S∙cm−1. For this purpose, we propose an approach concerning modifying the grain boundary composition towards the higher conducting one. To achieve this goal, Li4SiO4 was selected and added to the LATP base matrix to support Li+ diffusion between the grains. The properties of the Li1.3Al0.3Ti1.7(PO4)3−xLi4SiO4 (0.02 ≤ x ≤ 0.1) system were studied by means of high-temperature X-ray diffractometry (HTXRD); 6Li, 27Al, 29Si, and 31P magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR); thermogravimetry (TG); scanning electron microscopy (SEM); and impedance spectroscopy (IS) techniques. Referring to the experimental results, the Li4SiO4 additive material leads to the improvement of the electrical properties and the value of the total ionic conductivity exceeds 10−4 S∙cm−1 in most studied cases. The factors affecting the enhancement of the total ionic conductivity are discussed. The highest value of σtot = 1.4 × 10−4 S∙cm−1 has been obtained for LATP–0.1LSO material sintered at 1000 °C for 6 h. [ABSTRACT FROM AUTHOR]

Solid-state electrolytes have become a promising approach for rechargeable lithium batteries with enhanced safety and high energy density. However, the rigid nature of ceramic electrolytes would result in the poor interfacial contact, and polymer electrolytes suffer from inferior electrochemical performance and unsatisfied mechanical strength to suppress Li dendrites. In this work, we report a flexible Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP)-reinforced polyvinylidene fluoride (PVDF)-based solid composite electrolyte with superior performances in terms of high ionic conductivity (1.64 × 10−3 S cm−1 at room temperature), high lithium transference number (0.45), wide electrochemical window (0–4.76 V) and enhanced tensile strength (14.2 MPa). The existence of LATP permits the utilization of high Li-salt content which increases the charge carrier concentration. Meanwhile, LATP facilitates the Li+ conduction process and enhances the mechanical strength, leading to a long-term electrochemical stability of symmetric Li cell for 600 h at 0.2 mA cm−2. Assembled with LiFePO 4 cathode, the all-solid-state Li battery delivers a high capacity of 153.7 mA h g−1 at 0.3 C with remarkable cycle stability. This work provides a bright future for composite polymer electrolytes in the application of all-solid-state lithium batteries. • A LATP-reinforced PVDF-based solid-state composite electrolyte was prepared. • The existence of LATP permits the utilization of high Li-salt content. • A long-term electrochemical stability of the Li symmetric cell was achieved. • LiFePO 4 | CPE |Li battery delivers excellent cycle stability at room temperature. [ABSTRACT FROM AUTHOR]

Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) suffers from high interfacial resistance and instability with Li which hinder its application in all-solid-state lithium batteries. Herein, we propose an effective method to overcome these obstacles by introducing a LATP nanoparticle-reinforced composite polymer electrolyte (CPE) at LATP/Li interface. The multifunctional CPE interfacial layer can not only avoid side reactions between LATP and Li, but also ensure intimate contact at LATP/Li interface to reduce interfacial resistance. Moreover, the soft CPE layer can mitigate the large volume change of Li anode during cycling due to its high viscosity and flexible features. With the assistance of LATP fillers, the CPE interfacial layer can inhibit the formation and penetration of Li dendrites with enhanced mechanical strength and uniform Li deposition. After the modification of CPE interfacial layer, solid-state electrolyte with the sandwiched structure of CPE/LATP/CPE possesses satisfactory features such as high ionic conductivity, high interfacial stability and wide electrochemical window. Symmetric Li cell exhibits significant reduction in interfacial resistance (from 2852 Ω cm2 to 505 Ω cm2) and overpotential (from 2.03 V to 0.04 V), which ensures a stable galvanostatic cycle for more than 400 h at 0.05 mA cm−2. Solid-state LiFePO 4 /LATP/CPE/Li batteries deliver remarkable cycling ability and high coulombic efficiency. Image 1 • A multifunctional interfacial layer was introduced at LATP/Li interface. • Reduced interfacial resistance of Li/LATP/Li cell was achieved. • Li penetration has been successfully suppressed after long-term cycling. • All-solid-state batteries exhibit remarkable cycling performance at 80 °C. [ABSTRACT FROM AUTHOR]