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NASICON-structured Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) solid electrolyte has low grain boundary conductivity, which impedes its practical application. Herein, W was adopted to partially replace the Al element in LATP to improve its grain boundary conductivity. The W doping reduces the crystal lattice of the electrolyte, which is detrimental to the grain conductivity. But the doping of W can make the grains closely connect and reduce the voids between the grains, which can greatly enhance the grain boundary conductivity. The LATP sample with the W doping content of 0.03 (LATWP003) exhibits the highest total ionic conductivity of 1.186 mS/cm at 30 ℃, which results from the optimum grain boundary conductivity of 2.315 mS/cm. Moreover, the LATWP003 electrolyte displays a negligible electronic conductivity of 2.01×10−9 S/cm. The LiFePO 4 /LATWP003/Li battery with PVDF-HFP polymer protective layer can be charged and discharged. Therefore, the W doped LATP sample is a promising electrolyte for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Li1.3Al0.3Ti1.7(PO4)3 (LATP) electrolyte has a great potential for application in solid‐state lithium metal batteries. However, due to the poor interfacial contact and thermodynamic instability between LATP and Li metal, a series of interfacial problems, such as high interfacial resistance, undesirable interfacial reaction and dendrite growth are deeply criticized. Herein, a hybrid LiCl/LixSn conductive interlayer is constructed through an in situ electrochemical reaction of SnCl4 with Li metal to effectively improve the compatibility and stability of the Li/LATP interface. LiCl with both electronic insulation and high ionic conductivity can provide fast Li+ diffusion channel, block electron injection, avoid side reactions, and effectively inhibit dendrite growth. LixSn can reduce interfacial impedance, eliminate local electric field concentration, and significantly improve interfacial wettability. Under the protection of LiCl/LixSn hybrid interlayer, the initial resistance of the symmetric battery is reduced from 1066.3 to 133.6 Ω cm−2, achieving a high critical current density of 1.4 mA cm−2. At 0.1 mA cm−2/0.1 mAh cm−2 and 0.2 mA cm−2/0.2 mAh cm−2, the symmetric battery can cycle stably for more than 4000 h at 25 °C. Moreover, the full battery displays a high capacity retention ratio of 90.4% after 420 cycles at 0.5 C. [ABSTRACT FROM AUTHOR]

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]

Abstract—The effects of mechanical activation in a planetary mill and the addition of fusible additives on the conduction properties of the Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte with the NASICON structure are compared. According to the results of impedance measurements, the mechanical activation increases the total conductivity of this material from 0.57 × 10–4 to 1.20 × 10–4 S cm–1, whereas the introduction of 5 wt % of fusible additives LiPO3 and Li2B4O7 increases the conductivity to 1.53 × 10–4 and 1.50 × 10–4 S cm–1, respectively. The electronic conductivity of samples does not exceed 10–9–10–8 S cm–1. According to the temperature dependence of the conductivity, the LATP sample containing Li2B4O7 (5 wt %) demonstrates the lowest activation energy equal to 0.29 eV. [ABSTRACT FROM AUTHOR]

Abstract—The effects of mechanical activation in a planetary mill and the addition of fusible additives on the conduction properties of the Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte with the NASICON structure are compared. According to the results of impedance measurements, the mechanical activation increases the total conductivity of this material from 0.57 × 10–4 to 1.20 × 10–4 S cm–1, whereas the introduction of 5 wt % of fusible additives LiPO3 and Li2B4O7 increases the conductivity to 1.53 × 10–4 and 1.50 × 10–4 S cm–1, respectively. The electronic conductivity of samples does not exceed 10–9–10–8 S cm–1. According to the temperature dependence of the conductivity, the LATP sample containing Li2B4O7 (5 wt %) demonstrates the lowest activation energy equal to 0.29 eV. [ABSTRACT FROM AUTHOR]

Solid‐state batteries draw attention as next‐generation batteries that can provide higher energy density and overall stability based on the inherent nonflammability of the solid electrolytes. However, solid electrolytes have a clear limitation of low ionic conductivity due to their high resistance at grain boundaries and interfaces. Herein, oxide‐type solid electrolytes and ionic liquid electrolytes are introduced to reduce the overall resistance and form a clay‐textured composite electrolyte after a hybrid process. This composite electrolyte exhibits a stable state without side reactions and 1.6 ms cm−1 of improved ionic conductivity. This material also demonstrates its high thermal and electrochemical stability by high‐temperature exposure test and the application of bipolar configuration in conventional coin cells with high voltage. Therefore, this original clay‐textured pseudo‐solid‐state hybrid electrolyte is believed to contribute to the studies related to oxide‐type solid electrolytes for advanced solid‐state batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Superior Mg/Li separation coefficient. • Ultra low energy consumption. • Producing battery grade Li 2 CO 3 through two stages of simplified process. Traditional technologies of lithium extraction from salt lakes suffer the low efficiency of Li+/Mg2+ separation and high energy consumption. We introduce a novel electrodialysis process that leverages Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP, one of lithium superionic conductors) and incorporates an aided charge balance (ACB) system, all under low voltage and ultra-low current conditions. The remarkable ion selectivity of LATP, coupled with the enhanced recovery ratio facilitated by ACB, collectively empower this technology to achieve extremely high separation efficiency and remarkably low energy consumption. In a simulated pristine brine, the average Li/Mg separation coefficient reached 5924, accompanied by an exceptionally low energy consumption of only 0.80 kWh·kg−1 Li. Furthermore, this technique enabled the production of battery-grade Li 2 CO 3 with an outstanding purity of 99.93 %, achieved through a streamlined process comprising only two stages. [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]

In this work, the effect of carbon on the suppression of foaming during the solid-state synthesis of the Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) solid electrolyte was studied. According to thermal analysis data, mechanically activated mixtures with and without carbon exhibit similar behavior. The presence of carbon does not affect the gas release process during decomposition, and foaming suppression occurs due to the change in viscosity of the melt created by NH 4 H 2 PO 4. Slow LATP-S, medium LATP-M and fast LATP-F synthesis routes were used to evaluate the optimal conditions for LATP preparation. It was found that the use of carbon to suppress foaming eliminated the need for preheating and milling and reduced the synthesis time to 2.5 h (LATP-F). The effect of the synthesis route on the phase composition, morphology, conductive and electrochemical properties of LATP-S, LATP-M and LATP-F was investigated. No significant differences in studied properties were found for the synthesizer LATP samples excluding particle size distribution. Comparison of the granulometric curves showed that the fast synthesis method resulted in a decrease in particle size. The values of the ionic conductivity σ ion for LATP-S, LATP-M and LATP-F are equal to ∼10−4 S cm−1, while the electronic conductivity σ e does not exceed 10−9 S cm−1. The study of the electrochemical stability window of the synthesized LATP samples was showed that these solid electrolytes are stable up to 4.65–4.70 V. [Display omitted] • Using carbon to suppress foaming during LATP synthesis is a unique approach. • Foaming suppression reduces the LATP synthesis time to 2.5 h. • Carbon burns out and does not require additional steps to remove it from the LATP. • Addition of carbon during synthesis doesn't affect LATP properties. [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]

Poly(vinylidenefluoride-co-hexafluoropropylene) (P(VDF-HFP))/Li1.3Al0.3Ti1.7(PO4)3 (LATP)/P(VDF-HFP) sandwiched hybrid solid electrolytes were precisely tailored and successfully fabricated to assemble into all-solid-state lithium-ion batteries, which were systematically evaluated on microstructure, morphology, thermal stability and electrochemical performance. The sandwiched hybrid solid electrolytes can achieve intimate contact with cathode and anode electrodes to present an excellent interfacial stability. Furthermore, the sandwiched hybrid solid electrolytes possess flexible surface, wide electrochemical working window of 4.7 V, high ionic conductivity of 0.763 mS·cm−1 and high thermal stability of 460 °C, which may contribute to realizing the practical application in all-solid-state lithium-ion batteries. The assembled cells with the hybrid solid electrolytes can quickly stabilize at a specific discharge capacity of 145.4 mAh·g−1 at 0.1C after only 5 cycles and present admirable rate performance. In addition, morphology characterizations of the sandwiched hybrid solid electrolytes after long-term cycles show a relatively integrated structure coating with a compact LATP layer. The investigations afford a promising strategy that the sandwiched hybrid solid electrolytes can overcome the mechanical limitations of the interface between electrodes and inorganic solid electrolytes to provide favorable properties 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]

Sub-micron LATP solid electrolytes have been prepared via a facile microwave-assisted hydrothermal method. The structure and ionic conductivity of LATP has been investigated as a function of hydrothermal synthesis temperature by powder X-ray diffraction (XRD), thermal analysis, scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The hydrothermal synthesis temperature is pivotal in controlling the uniformity of the LATP particle size distribution and the surface morphology of the electrolyte. Optimal LATP pellets prepared from powder synthesized at 180 °C exhibit an ionic conductivity of 1.4 × 10−4 S cm−1 at 298 K, while variable temperature measurements yielded activation energy of 0.253 eV for Li diffusion. These favorable values could reflect the uniform particle size distribution, high crystallinity and a relative density as high as 97 %. The optimum electrolyte material was applied in an NCM523/LATP/Graphite pouch cell, which demonstrated a stable capacity (≥ 92.5 % at a Coulombic efficiency of ∼100 %) for >400 cycles. The results indicate that LATP synthesized by microwave-assisted hydrothermal methods performs very effectively as a solid electrolyte and is a credible candidate for all - solid-state LIBs. [Display omitted] • Li1.3Al0.3Ti1.7(PO4)3 (LATP) was synthesized by a microwave-assisted hydrothermal reaction. • The hydrothermal synthesis temperature plays an important role in determining the morphology and density of the LATP. • The parameter-optimized LATP delivers an ionic conductivity of >1.4 × 10–4 S cm−1. • NCM523/LATP/Graphite all-solid-sate pouch cells are demonstrated. [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]

Hydrothermal synthesis is used to successfully prepare Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolytes with high lithium‐ion conductivity, typically being 0.213 mS cm−1. The best calcination and sintering temperatures are optimized to be 900 and 1075 °C, respectively. The solvent effects on conductivity and microstructure of LATP in water, ethanol and acetone are investigated by using impedance spectroscopy and scanning electron microscopy. The conductivity of LATP in water reaches 1.167 mS cm−1. In ethanol, the conductivity of LATP is 0.464 mS cm−1. There is no significant change in acetone. The structural stability of LATP after immersing in liquid solutions is verified by X‐ray diffraction and Raman spectroscopy. It is found by infrared spectroscopy that the change in conductivity is related to the adsorbed OH bond, and the reason for the increase in conductivity is discussed. [ABSTRACT FROM AUTHOR]

NASICON-type fast ion conductor powders Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) are prepared by spray-drying and sintering processes confirmed by XRD and SEM analyses. Novel poly(vinylidene fluoride-hexafluoropylene) (P(VDF-HFP))-based composite polymer electrolytes (CPEs) doped with various amounts of LATP particles are fabricated via classical inverse-phase method. As a result, the as-prepared CPE-5 membrane can present excellent physicochemical properties when the doped amount is maintained at 5% vs. polymer matrix, in which the interfacial impedance value can rapidly stabilize at 472 Ω and the thermal decomposition temperature can be up to 430 °C, respectively. In particularly, the ionic conductivity can be as high as 3.943 mS cm−1 at 25 °C. In addition, the assembled LiCoO 2 /CPE-5/Li coin cell can deliver a discharge specific capacity of 145.4 mAh g−1 at 1.0 C with 96.93% capacity retention ratio after 25 cycles. These outstanding properties can promote the CPE-5 to be a candidate electrolyte to improve the performance of lithium ion batteries. Brief preparation process and characterization of composite polymer electrolytes doped with various amounts of LATP powders. Unlabelled Image • NASICON-type LATP powders are prepared by spray-drying and sintering methods. • The optimum LATP doping amount is 5% vs. polymer matrix. • The ionic conductivity at room temperature is as high as 3.943 mS cm−1. • The assembled cell delivers a discharge specific capacity of 132.8 mAh g−1 at 1.0 C. [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]

Abstract NASICON-type ceramic electrolyte has been considered as one of the potential candidates for solid state electrolytes with excellent conductivity at room temperature and good stability under atmosphere. In this paper, NASICON-type Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) was prepared by a solution method and dispersed in poly(vinylidene fluoride) (PVDF) to form LATP/PVDF composite electrolyte membranes (CEM) by the method of casting. The effects of LATP filler on the structure, morphology, ionic conductivity, stability of the LATP/PVDF CEM were studied. It was found that the LATP/PVDF CEM had high lithium ion conductivity and excellent electrochemical stability with the electrochemical stability window up to 5.67 V versus Li+/Li. The discharge capacity of lithium iron phosphate cells assembled with LATP/PVDF CEM was 163.5 mAh g−1 and retained over 95.7% of its initial capacity after 50 cycles. The results show that the addition of LATP filler to PVDF matrix increases the amorphous phase of the polymer by acting as a gel center and the concentration of Li+ is increased, which is beneficial to the synergism in the migration of Li+ and enhances the ionic conductivity. Highlights • Preparation of a new type of lithium ion composite electrolyte material. • Inorganic fast ion conductor and organic polymer composite membrane. • Novel composite membrane has good thermal stability and chemical stability. • Wide electrochemical window, high capacity and good cycling stability. [ABSTRACT FROM AUTHOR]

Solid electrolytes are crucial in obtaining high safety standards and high energy densities in all-solid-state batteries (ASSBs). For ASSBs, it is essential to design solid electrolytes with high ionic conductivity. Herein, a density functional theory (DFT) study has been conducted to investigate the impact of substitutional sulfur doping into Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) solid electrolyte which has a sodium superionic conductor (NaSICON) type crystal structure. A comprehensive study of the effect of sulfur doping on structural stability, Li-ion migration path, and electronic properties was carried out. DFT calculations indicate that sulfur doping locally improves the Li-ion migration kinetics which is accompanied by increased polyhedral volumes in the diffusion path. Moreover, experimental and computational studies were carried out on the electronic state of bare and sulfur-doped LATP. Band gap measurements performed by UV–Vis absorption analysis revealed that sulfur doping decreased the band gap from 2.35 eV to 2.10 eV in alignment with the theoretical calculations in which 1.83 eV was obtained in the most stable sulfur-doped configuration. Compared with bare-LATP, it has been validated that S@LATP has better ionic conductivity with reducing activation energy barrier as a solid electrolyte for all-solid-state batteries. [ABSTRACT FROM AUTHOR]

In this study, B3+ and In3+ ions were co-doped at the Al3+ sites of Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 electrolyte using a solid-state reaction with the goal of obtaining electrolytes with remarkable Li-ion conductivities. B3+-ion doping enhanced the densification of Li 1.3 Al 0.3-y B y Ti 1.7 (PO 4) 3 electrolytes, and Li 1.3 Al 0.22 B 0.08 Ti 1.7 (PO 4) 3 electrolyte delivered the highest relative density of 97.6%. Subsequent In3+-ion doping further enhanced densification, and Li 1.3 Al 0.21 B 0.08 In 0.01 Ti 1.7 (PO 4) 3 electrolyte delivered the highest relative density of 98.2%. However, the electrolyte densification diminished rapidly upon further increasing the In3+-ion content. The peaks in the X-ray diffraction patterns of the Li 1.3 Al 0.3-y B y Ti 1.7 (PO 4) 3 and Li 1.3 Al 0.22-x B 0.08 In x Ti 1.7 (PO 4) 3 electrolytes were indexed to rhombohedral NASICON-type LiTi 2 (PO 4) 3 with the space group R 3 ¯ c with trace amounts of LiTiPO 5 secondary phase. Upon incorporating In3+ ions into the lattice of Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 solid electrolyte, the cell volume and the transport channels for Li+ ions were expanded, while B3+-ion incorporation slightly contracted the cell. The scanning electron microscopy and Raman spectroscopy results indicated that B3+-ion substitution into the Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 lattice to obtain Li 1.3 Al 0.3-y B y Ti 1.7 (PO 4) 3 electrolytes, which led to the increase in the structural order of the lattices and promoted the formation of microstructures with superior crystallinity and smaller and more uniform grain sizes. Further, B3+ and In3+-ions co-doped Li 1.3 Al 0.22-x B 0.08 In x Ti 1.7 (PO 4) 3 electrolytes showed lower structural order, larger grain size, lower grain-size uniformity, and more pore contents than those of undoped Li 1.3 Al 0.3 Ti 1.7 (PO 4). The ionic conductivities of the Li 1.3 Al 0.3-y B y Ti 1.7 (PO 4) 3 electrolytes increased with increasing concentration of B3+-ion dopant and reached a maximum of 8.35× 10−4 S/cm for Li 1.3 Al 0.22 B 0.08 Ti 1.7 (PO 4) 3. Among the Li 1.3 Al 0.22-x B 0.08 In x Ti 1.7 (PO 4) 3 electrolytes, Li 1.3 Al 0.21 B 0.08 In 0.01 Ti 1.7 (PO 4) 3 presented the highest ionic conductivity of 1.08 × 10−3 S/cm, which was closely correlated to its high relative density. The contribution of electronic conductivity to total conductivity was found to be trivial. • Co-doping of B3+ and In3 increased the relative densities of Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3. • Cell volume and transport paths for Li+ ions swelled due to In3+ co-doping. • Li 1.3 Al 0.21 B 0.08 In 0.01 Ti 1.7 (PO 4) 3 has the highest conductivity of 1.08 × 10−3 S/cm. • Boost of ion conductivities is closely related to the densification of electrolyte. [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]

NASICON-type Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) has attracted a lot of attention because of its high ionic conductivity and stability to air and moisture. However, the size effect of LATP primary particles on ionic conductivity is ignored. In this study, different sizes of LATP particles are prepared to investigate the morphology, relative density, and ionic conductivity of the LATP solid electrolyte. The influences of particle size and sintering temperature on the microstructure, phase composition, and electrical properties of LATP ceramics were systematically studied. The medium-sized LATP particle (2 μm) presents a great microstructure with a high relative density of over 97%, the highest ionic conductivity of 6.7 × 10 -4 S cm -1 , and an activation energy of 0.418 eV. The Li-Li symmetric cells and Li-LFP batteries delivering good electrochemical performance were fabricated with highly conductive LATP ceramics. These results make significant strides in elucidating the relationship between the particle sizes of LATP and its electrochemical performance.

All-solid-state lithium metal batteries (ASSLMBs), as a candidate for advanced energy storage devices, invite an abundance of interest due to the merits of high specific energy density and eminent safety. Nevertheless, issues of overwhelming lithium dendrite growth and poor interfacial contact still limit the practical application of ASSLMBs. Herein, we designed and fabricated a double-layer composite solid electrolyte (CSE), namely, PVDF-LiTFSI-Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 /PVDF-LiTFSI- h- BN (denoted as PLLB), for ASSLMBs. The reduction-tolerant PVDF-LiTFSI- h- BN (denoted as PLB) layer of the CSE tightly contacts with the Li metal anode to avoid the reduction of LATP by the electrode and participates in the formation of a stable SEI film using Li 3 N. Meanwhile, the oxidation-resistance and ion-conductive PVDF-LiTFSI- LATP (denoted as PLA) layer facing the cathode can reduce the interfacial impedance by facilitating ionic migration. With the synergistic effect of PLA and PLB, the Li/Li symmetric cells with sandwich-type electrolytes (PLB/PLA/PLB) can operate for 1500 h with ultralong cycling stability at 0.1 mA cm -2 . Additionally, the LiFePO 4 /Li cell with PLLB maintains satisfactory capacity retention of 88.2% after 250 cycles. This novel double-layer electrolyte offers an effective approach to achieving fully commercialized ASSLMBs.

• The ZnO layer is introduced on the interface between LATP and Li. • The layer can inhibit the growth of Li dendrites and improve structural stability. • The Li/zno@LATP@zno/Li cell exhibits excellent cycle performance for 500 h. • The licoo 2 /zno@LATP/Li cell remains 118.5 mAh g−1 after 100 cycles at 0.1 c at 25 °C. Spherical Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) solid electrolyte powders are first successfully synthesized by spray-drying and O 2 pressure-controlled calcination processes, and then the targeted ZnO@LATP composite solid electrolytes are gained by coating 2 μm thickness of ZnO layer on the surface of the LATP powders, in which the ZnO layer effectively not only isolates the direct contact between LATP electrolyte sheet and lithium metal electrode, but also regulates the lithium deposition reaction on the surface of the electrolytes, thereby restraining the overgrowth of lithium dendrites to prolong the life span of the assembled coin cell. Specifically, the Li/ZnO@LATP@ZnO/Li symmetric cell enhances the cycle stability without obvious increment of the overpotential compared to the Li/LATP/Li cell at 0.4 mA cm−2 for 500 h, and the assembled LiCoO 2 /ZnO@LATP/Li coin cell can deliver excellent rate and cycling performance, in which the discharge specific capacity is still retained at 118.5 mAh g−1 after 100 cycles at 0.1 C and quickly recovers to 121.2 mAh g−1 when the current is set back to 0.1 C after cycles. Furthermore, the ZnO@LATP solid electrolyte powders after being cycled present integrally spherical shape without any remarkable crack compared with the LATP solid electrolyte powders. Therefore, the investigations may provide an effective strategy to significantly lower the probability of side reactions between LATP electrolyte and lithium metal electrode to promote the electrochemical properties of LATP-based all-solid-state lithium-ion batteries. Schematic diagram of the structural stability and the cycling performance of the as-prepared solid electrolytes with and without the ZnO layer [Display omitted] [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]

Mechanical activation (MA) has been used to prepare high dispersed lithium-transition metal cathode materials and inorganic solid lithium-ion electrolytes for rechargeable lithium batteries. It has been shown that materials with low-dimensional (submicron) particles have notable advantages: i) for insertion electrodes, i.e. when the first electrochemical step is intercalation of Li+ ions (eg., LiMn2O4–3V, LiV3O8); ii) for cathodes with poor electronic conductivity (eg., LiFePO4); iii) for materials (electrodes and electrolytes) used in all solid state inorganic lithium batteries. Decreased particle size of as prepared cathodes leads to enhanced practical capacity because of increased quantity of particles that can be utilized, while the presence of structural disordering results in better structural stability upon intercalation of lithium ions and smoother discharge curves. The conductivity of the LiTi2(PO4)3 and Li1.3Al0.3Ti1.7(PO4)3 lithium-ion solid electrolytes prepared by using MA was of 2–3 order of magnitude higher than that for nonactivated samples owing to the absence of non-conductive impurities and lower grain boundary resistance. [Copyright &y& Elsevier]

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]

Te-doped NASICON-type Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) electrolyte materials were prepared by ball milling-assisted solid state method. The structural, morphological, and transport properties of samples were analyzed through X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscope, energy dispersive X-Ray spectroscopy, electrochemical impedance spectroscopy, and DC polarization to determine optimal doping concentration. High total ionic conductivity of 7.03 × 10−4 S cm−1 and negligible electronic conductivity of 7.64 × 10−9 S cm−1 were obtained at room temperature for Li 1.3 Al 0.3 Te 0.03 Ti 1.67 (PO 4) 3 electrolyte. Interface characteristics analysis of electrolyte materials with Li electrode showed that voltage profile of Li/Li 1.3 Al 0.3 Te 0.03 Ti 1.67 (PO 4) 3 /Li cell remained stable after 300 h of cycling with current density of 0.02 mA cm−2. Good cyclic stability at different temperatures was also demonstrated, with doped electrolyte presenting better interface stability than pure LATP. These results suggest that Te-doped LATP materials can be used as alternative solid electrolyte for all solid-state lithium-ion batteries. [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]

Lithium-ion batteries (LIBs) with liquid electrolytes (LEs) have problems such as electrolyte leakage, low safety profiles, and low energy density, which limit their further development. However, LIBs with solid electrolytes are safer with better energy and high-temperature performance. Thus, solid electrolyte system batteries have attracted widespread attention. However, due to the inherent rigidity of the LATP solid electrolyte, there is a high interface impedance at the LATP/electrode. In addition, the Ti element in LATP easily reacts with the Li metal. Here, we dripped an LE at the LATP/electrode interface (solid-liquid hybrid electrolytes) to reduce its interface impedance. A composite polymer electrolyte (CPE) protective film (containing PVDF, SN, and LiTFSI) was then cured in situ at the LATP/Li interface to avoid side reactions of LATP. The discharge specific capacity of the LiFePO 4 /LATP-12% LE-CPE/Li system is up to 150 mAh g -1 , and the capacity retention rate is still 96% after 250 cycles. In addition, the NCM622/PVDF-LATP-12% LE/Li system has an initial reversible capacity of 170 mAh g -1 . This study reports an approach that can protect solid electrolytes from lithium metal instability.

The practical use of lithium-sulfur (Li-S) batteries is limited by serious self-discharge, fast capacity loss, and severe lithium anode erosion due to the shuttling of lithium polysulfides (LiPSs). Herein, we developed a highly efficient ion and electron conductive interlayer composed of Ti 2 (SO 4 ) 3 /carbon composite layer-coated Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (CLATP) and graphene to effectively block the diffusion of polysulfide anions but allow rapid Li ion transfer, therefore significantly inhibiting the self-discharge and boosting the cyclic stability of Li-S batteries. The Ti 2 (SO 4 ) 3 /carbon thin protective layer endows an optimized adsorption ability toward LiPSs and avoids the side reactions between LATP and LiPSs. The high electronic conductivity of graphene and high ionic conductivity of CLATP ensures the hybrid interlayer rapid electron and fast Li ion transport. As a result, the Li-S battery with the hybrid interlayer shows a high discharge capacity of 671 mAh g -1 after 500 cycles with an extremely low capacity fading of 0.022% per cycle at 1 C. Moreover, the battery shows no self-discharge even after rest for 12 days. This work opens up a new way for the design of functional separators to significantly improve the electrochemical performance of Li-S batteries.