Lithium Aluminum Titanium Phosphate Research Articles

High-resolution Li depth profiling in a thin-film all-solid-state battery using TOF-ERDA

A quantitative understanding of the Li distribution inside all-solid-state Li-ion batteries is important for improving the performance of batteries. We constructed a time-of-flight (TOF) elastic recoil detection analysis (ERDA) system for operando measurements of thin-film Li-ion batteries. The TOF-ERDA measurement provides elementally resolved spectra with a depth resolution much higher than that of conventional stopper-foil ERDA. The Li depth profiles in a cathode film and solid electrolyte were obtained quantitatively to a depth of 100 nm using a 9-MeV Cu ion beam with reflection geometry. In this study, we conducted TOF-ERDA for a thin-film battery having a cathode made from LiCoO2, an oxide-based solid electrolyte [lithium aluminum titanium phosphate (LATP)], and an anode made from Fe2(MoO4)3 to demonstrate the ability of the measurement system and reveal the Li distribution near the interface with improved resolution. The depth resolution at the interface (30 nm from the surface) was estimated to be 12–14 nm. We quantitatively obtained the Li density in the LiCoO2 cathode and the variation in the Li distribution around the LiCoO2/LATP interface and inside the LATP electrolyte upon charging/discharging. TOF-ERDA is thus a powerful tool for the high-resolution quantitative depth analysis of Li in thin-film batteries in operando.

Novel yttrium and silicon co‐doped Li1.3+x+yAl0.3−xYxTi1.7Siy(P1−yO4)3 solid electrolyte for lithium batteries: Effect on ionic conductivity and crystal structure

AbstractDoping of superfast ionic conductors like NASICON has been shown to boost ionic conductivity and the efficiency of lithium batteries. NASICON‐type yttrium and silicon‐doped lithium aluminum titanium phosphate (LATP) solid electrolytes have been synthesized via the conventional solid‐state method at different sintering temperatures. Their intrinsic physical, chemical, and electrochemical properties are analyzed using x‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, x‐ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. Yttrium and silicon co‐doped LATP (LAYTSP) powder sintered at 900°C exhibits homogeneous hexagonal morphology and better crystallinity than the pure LATP solid electrolyte synthesized by the same methodology. LAYSTP demonstrated a higher ionic conductivity of 5.98 × 10−6 S/cm at ambient conditions. Mixing 5%‐LiCl with LAYTSP‐900°C improved the ionic conductivity significantly up to 1.88 × 10−4 S/cm. Cell viability testing demonstrated that our cells exhibit long‐term stability and are suitable for applications requiring sustained high voltages.

Converting a Commercial Separator into a Thin‐film Multi‐Layer Hybrid Solid Electrolyte for Li Metal Batteries

AbstractTo address the manifold challenges solid electrolytes (SE) do face in NMC‖Lithium metal batteries, we demonstrate that these can be overcome by converting a commercial Celgard 2500 separator into a jack of all trades hybrid solid electrolyte (HSE). This approach follows a multi‐layer electrolyte strategy, to better cope with the very different chemistries of the cathode, the bulk electrolyte material, and the Li metal anode. A cathode‐facing electrolyte layer based on lithium aluminum titanium phosphate (LATP) provides a high voltage stability of ≥4.5 V. High mechanical strength of the overall thin film electrolyte (≤50 μm) is achieved with a middle layer based on Celgard 2500. The layer on the anode side, based on polyethylene oxide (PEO), allows stable cycling of the lithium metal. High Coulombic efficiencies in NMC622‖Li metal cells (99.9 %) and LFP‖Li metal cells (99.9 %) enable long term cycling with high‐capacity retention of 46 % and 52 % after 1,000 cycles, respectively.

Technological Advances and Market Developments of Solid-State Batteries: A Review.

Batteries are essential in modern society as they can power a wide range of devices, from small household appliances to large-scale energy storage systems. Safety concerns with traditional lithium-ion batteries prompted the emergence of new battery technologies, among them solid-state batteries (SSBs), offering enhanced safety, energy density, and lifespan. This paper reviews current state-of-the-art SSB electrolyte and electrode materials, as well as global SSB market trends and key industry players. Solid-state electrolytes used in SSBs include inorganic solid electrolytes, organic solid polymer electrolytes, and solid composite electrolytes. Inorganic options like lithium aluminum titanium phosphate excel in ionic conductivity and thermal stability but exhibit mechanical fragility. Organic alternatives such as polyethylene oxide and polyvinylidene fluoride offer flexibility but possess lower ionic conductivity. Solid composite electrolytes combine the advantages of inorganic and organic materials, enhancing mechanical strength and ionic conductivity. While significant advances have been made for composite electrolytes, challenges remain for synthesis intricacies and material stability. Nuanced selection of these electrolytes is crucial for advancing resilient and high-performance SSBs. Furthermore, while global SSB production capacity is currently below 2 GWh, it is projected to grow with a >118% compound annual growth rate by 2035, when the potential SSB market size will likely exceed 42 billion euros.

Cathode Interface Construction by Rapid Sintering in Solid-State Batteries.

Solid-state batteries (SSBs) are poised to replace traditional organic liquid-electrolyte lithium-ion batteries due to their higher safety and energy density. Oxide-based solid electrolytes (SEs) are particularly attractive for their stability in air and inability to ignite during thermal runaway. However, achieving high-performance in oxide-based SSBs requires the development of an intimate and robust SE-cathode interface to overcome typically large interfacial resistances. The transition interphase should be both physically and chemically active. This study presents a thin, conductive interphase constructed between lithium aluminum titanium phosphate and lithium cobalt oxide using a rapid sintering method that modifies the interphase within 10s. The rapid heating and cooling rates restrict side reactions and interdiffusion on the interface. SSBs with thick composite cathodes demonstrate a high initial capacity of ≈120mAhg-1 over 200 cycles at room temperature. Furthermore, the rapid sintering method can be extended to other cathode systems under similar conditions. These findings highlight the importance of constructing an appropriate SE-cathode interface and provide insight into designing practical SSBs.

Constructing PTFE@LATP composite solid electrolytes with three-dimensional network for high-performance lithium batteries

The NASICON-type lithium aluminum titanium phosphate (LATP) solid-state electrolytes is considered as a promising candidate for next-generation all-solid-state lithium batteries (ASSLBs) with high energy density. However, LATP possesses highly interfacial impedance, causing poor electrochemical performance of ASSLBs and seriously hindering its practical application. Herein, the (polytetrafluoroethylene) PTFE@LATP composite solid electrolytes with three-dimensional network have been constructed by combining sol-gel and solid state grinding methods. The electrochemical performance test results show that the introduction of 24 wt% PTFE can effectively reduce the interface impedance of LATP (LATP:2010.0 Ω, PTFE@LATP:126.9 Ω), increased ion conductivity of LATP (LATP:5.50 × 10−5 S∙cm−1, PTFE@LATP:7.56 × 10−4 S∙cm−1), further significantly improve the electrochemical window (LATP:3.2 V, PTFE@LATP:5.0 V), rate capability (corresponds to 95.2% of the initial discharge capacity) and cycling stability (the capacity of the full cell is changed from 140.1 mAh∙g−1 to 88.3 mAh∙g−1 after 500 cycles at 1 C) of ASSLBs. Mechanism research indicates that PTFE@LATP with the excellent electrochemical performance benefits from PTFE@LATP CSEs with three-dimensional network and electrode possess well interface compatibility, it conducive to preventing the occurrence of interface side reactions and promoting the rapid migration of lithium ions. This work provides a theoretical basis and practical guidance for the further development of CSEs with higher electrochemical performance.

A Novel Approach for Development of Stable Quasi‐Solid Lithium‐O2 Batteries: Assembly and Performances of Double Layer Gel Polymer Electrolytes

AbstractGel‐polymer electrolytes (GPEs) offer a suitable alternative to flammable organic liquid electrolytes in lithium‐oxygen batteries (LOBs) to address safety concerns. However, a major challenge with GPEs is their low ionic conductivity. To enhance the ionic conductivity of GPEs, active inorganic particles have been incorporated. To increase the ionic conductivity of GPE, active inorganic particles have been reinforced in GPE. While this increases the ionic conductivity, it also leads to blockage of the cathode porous structure and reduces the actual surface area of the cathode materials, resulting in poor battery performance. This study proposes a novel double‐layer polymer gel electrolyte (d‐GPE) that exhibits both high ionic conductivity and stability for quasi solid‐state LOBs. The double‐layer GPE consists of a bare GPE layer integrated in the cathode, and a composite GPE (c‐GPE, containing 5 wt. % lithium aluminum titanium phosphate (LATP)), which is in contact with Li anode and bare‐GPE. The produced double‐layer gel polymer electrolyte displays high reaction kinetic and better stability due to the excellent electrode/electrolyte interface and rapid oxygen diffusion in the air‐cathode. Furthermore, the d‐GPE electrolyte is resistant to fire and protects Li from dendrite growth and water molecules attack, indicating tremendous promise for the development of practical LOBs.

Roles of Lithium Aluminum Titanium Phosphate in Lithium Batteries

Roles of Lithium Aluminum Titanium Phosphate in Lithium Batteries

Stable interface between anode materials and Li1.3Al0.3Ti1.7(PO4)3-based solid-state electrolyte facilitated by graphene coating

A graphene surface coating strategy (G@LATP), to modify and improve the interfacial characteristics between the Lithium Aluminum Titanium Phosphate (LATP) electrolyte and different anodes, such as Li metal and Si film has been proposed. As a result, the Li/Li symmetric cell with graphene coating modified LATP electrolyte exhibits excellent cyclic stability, even at large current densities of 0.5 mA·cm−2 and 1 mA·cm−2. The modified Li/G@LATP/LiFePO4 solid-state full cell is delivering a discharge specific capacity of 136 mAh·g−1 after 200 cycles at a current density of 0.1 mA·cm−2, corresponding to a capacity retention of 86.1%. The graphene coating technique also led to improved cyclic stability in the Si/Si symmetric cell with modified LATP electrolyte at current densities of 0.1 mA·cm−2 and 0.3 mA·cm−2, with polarization voltages of 0.063 V and 0.27 V after cycling for 1000 h, respectively. Moreover, the Si/G@LATP/LiFePO4 full cell shows an outstanding discharge specific capacity of 161 mAh·g − 1 at its 2nd cycle, with a capacity retention of 92.9% after 200 cycles. These results show that graphene coating of the LATP electrolyte is a facile and effective method to improve the interfacial characteristics of Li/LATP and Si/LATP.

Quasi-Solid-State Lithium-Sulfur Batteries Assembled by Composite Polymer Electrolyte and Nitrogen Doped Porous Carbon Fiber Composite Cathode

Solid-state lithium sulfur batteries are becoming a breakthrough technology for energy storage systems due to their low cost of sulfur, high energy density and high level of safety. However, its commercial application has been limited by the poor ionic conductivity and sulfur shuttle effect. In this paper, a nitrogen-doped porous carbon fiber (NPCNF) active material was prepared by template method as a sulfur-host of the positive sulfur electrode. The morphology was nano fiber-like and enabled high sulfur content (62.9 wt%). A solid electrolyte membrane (PVDF/LiClO4/LATP) containing polyvinylidene fluoride (PVDF) and lithium aluminum titanium phosphate (Li1.3Al0.3Ti1.7(PO4)3) was prepared by pouring and the thermosetting method. The ionic conductivity of PVDF/LiClO4/LATP was 8.07 × 10−5 S cm−1 at 25 °C. The assembled battery showed good electrochemical performance. At 25 °C and 0.5 C, the first discharge specific capacity was 620.52 mAh g−1. After 500 cycles, the capacity decay rate of each cycle was only 0.139%. The synergistic effect between the composite solid electrolyte and the nitrogen-doped porous carbon fiber composite sulfur anode studied in this paper may reveal new approaches for improving the cycling performance of a solid-state lithium-sulfur battery.

Phase Evolution and Li Diffusion in LATP Solid‐State Electrolyte Synthesized via a Direct Heat‐Cycling Method

Herein, the direct synthesis of phase‐pure lithium aluminum titanium phosphate (Li1.3Al0.3Ti1.7(PO4)3, LATP) solid‐electrolyte powder in 220 min and relatively low temperatures (850 °C) is achieved via a new (cyclic) fast heat treatment (c‐FHT) route. The complex structural evolution highlights rate‐limited lithium incorporation of intermediate metal phosphates formed prior to the final phase‐pure LATP. The prepared LATP product powder displays similar bulk (2 × 10−10 cm2 s−1) and local (3 × 10−10 cm2 s−1) values for lithium diffusion coefficients (DLi) characterized by electrochemical impedance spectroscopy and muon spin relaxation (μSR), respectively. The similarity between both DLi values suggests excellent retention of inter‐ and intraparticle lithium diffusion, which is attributed to the absence of deleterious surface impurities such as AlPO4. A low‐energy barrier (Ea = 73 meV) of lithium diffusion is also estimated from the μSR data.

Highly safe and stable Li–CO2 batteries using conducting ceramic solid electrolyte and MWCNT composite cathode

This study demonstrates a Li–CO2 battery with lithium aluminum titanium phosphate (LATP) solid electrolyte and carbon cloth-based multi-walled carbon nanotubes (MWCNTs) cathode. The LATP powder is synthesized by a facile solution-based method. The structural properties of as-prepared LATP are evaluated using X-ray diffraction (XRD) and Rietveld refinement analysis. The ionic conductivity of the LATP pellet is measured by electrochemical impedance spectroscopy (EIS) and found to be ∼5.43 × 10−4 S cm−1. Further, the morphology of the carbon cathodes with MWCNTs is examined by scanning electron microscopy (SEM). The electrochemical performance is evaluated by galvanostatic tests at a current density of 60 mA g−1 with a cut-off capacity of 600 mAh g−1 for 50 cycles. The test results signify the high performance and good cyclic stability. The Li–CO2 cell has delivered a maximum capacity of 5255 mAh g−1. Finally, to investigate further, post mortem analysis is carried out in which the discharge products are thoroughly characterized by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). This work also introduces a new geometry for Li–CO2 batteries with LATP as the solid electrolyte, enabling the development of all-solid-state batteries.

A simple preparation process of lithium titanium aluminum phosphate solid electrolyte with ultra-high ionic conductivity

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.

High-Content Lithium Aluminum Titanium Phosphate-Based Composite Solid Electrolyte with Poly(ionic liquid) Binder.

Solid electrolytes have been regarded as the most promising electrolyte materials for the next generation of flexible electronic devices due to their excellent safety and machinability. Herein, composite solid electrolytes (CSE) with “polymer in ceramic” are prepared by using lithium aluminum titanium phosphate (LATP) as a matrix and modified poly(ionic liquid) as a binder. The results revealed that adding a poly(ionic liquid)-based binder not only endowed good flexibility for solid electrolytes, but also significantly improved the ionic conductivity of the electrolytes. When the content of LATP in the CSE was 50 wt.%, the electrolyte obtained the highest ionic conductivity (1.2 × 10−3 S·cm−1), which was one order of magnitude higher than that of the pristine LATP. Finally, this study also characterized the compression resistance of the composite solid-state electrolyte by testing the Vickers hardness, and the results showed that the hardness of the composite solid-state electrolyte can reach 0.9 ± 0.1 gf/mm2 at a LATP content of 50 wt.%.

Machine Learning Assisted Design of Experiments for Solid State Electrolyte Lithium Aluminum Titanium Phosphate

Lithium-ion batteries with solid electrolytes offer safety, higher energy density and higher long-term performance, which are promising alternatives to conventional liquid electrolyte batteries. Lithium aluminum titanium phosphate (LATP) is one potential solid electrolyte candidate due to its high Li-ion conductivity. To evaluate its performance, influences of the experimental factors on the materials design need to be investigated systematically. In this work, a materials design strategy based on machine learning (ML) is employed to design experimental conditions for the synthesis of LATP. In the variation of parameters, we focus on the tolerance against the possible deviations in the concentration of the precursors, as well as the influence of sintering temperature and holding time. Specifically, models built with different design selection strategies are compared based on the training data assembled from previous laboratory experiments. The best one is then chosen to design new experiment parameters, followed by measuring the corresponding properties of the newly synthesized samples. A previously unknown sample with ionic conductivity of 1.09 × 10−3 S cm−1 is discovered within several iterations. In order to further understand the mechanisms governing the high ionic conductivity of these samples, the resulting phase compositions and crystal structures are studied with X-ray diffraction, while the microstructures of sintered pellets are investigated by scanning electron microscopy. Our studies demonstrate the advantages of applying machine learning in designing experimental conditions by the synthesis of desired materials, which can effectively help researchers to reduce the number of required experiments.

Coupling Water-Proof Li Anodes with LiOH-Based Cathodes Enables Highly Rechargeable Lithium-Air Batteries Operating in Ambient Air.

Realizing an energy‐dense, highly rechargeable nonaqueous lithium–oxygen battery in ambient air remains a big challenge because the active materials of the typical high‐capacity cathode (Li2O2) and anode (Li metal) are unstable in air. Herein, a novel lithium–oxygen full cell coupling a lithium anode protected by a composite layer of polyethylene oxide (PEO)/lithium aluminum titanium phosphate (LATP)/wax to a LiOH‐based cathode is constructed. The protected lithium is stable in air and water, and permits reversible, dendrite‐free lithium stripping/plating in a wet nonaqueous electrolyte under ambient air. The LiOH‐based full cell reaction is immune to moisture (up to 99% humidity) in air and exhibits a much better resistance to CO2 contamination than Li2O2, resulting in a more consistent electrochemistry in the long term. The current approach of coupling a protected lithium anode with a LiOH‐based cathode holds promise for developing a long‐life, high‐energy lithium–air battery capable of operating in the ambient atmosphere.

Bistrifluoroacetamide‐Activated Double‐Layer Composite Solid Electrolyte for Dendrite‐Free Lithium Metal Battery

AbstractThe achievement of high ionic conductivity for solid‐state electrolyte and low interface resistance between electrodes and electrolyte are keys to successful solid‐state lithium ion batteries. In this paper, an efficient solid‐state electrolyte with dual‐layer structure for dendrite‐free lithium metal battery is designed. A Li metal‐friendly poly(ethylene oxide) (PEO) can serve as low‐voltage stable polymer electrolyte and ceramic‐dominating poly(vinylidene fluoride)–lithium aluminum titanium phosphate (PVDF–LATP) composite solid electrolyte is able to resist higher voltage facing cathode. More importantly, bistrifluoroacetamide (BTFA), as a polar molecular plasticizer, can simultaneously inhibit polymer crystallization, coordinate the delocalization of negative charges, and facilitate the solvation of lithium salts, providing absorption sites for lithium ion migration. The obtained BTFA‐activated PEO/PVDF–LATP double‐layer solid electrolyte exhibits satisfied ionic conductivity (4.4 × 10−4 S cm−1 at 25 °C), high Li+‐transfer number (0.68), and wide electrochemical stable windows (0–5.092 V vs Li/Li+). Moreover, both the assembled full cells with LiFePO4 and high‐voltage LiNi0.8Co0.1Mn0.1O2 cathodes show high initial discharge capacities (163.3 and 219.5 mAh g−1 at 0.1 C, respectively), excellent cycling, and rate performance.

Cathode Surface Engineering with Ceramic Solid Electrolytes for Li-Ion Batteries Performance Enhancement

An unprotected cathode of a lithium-ion battery (LIB) cell using lithium metal anode and organic carbonate liquid electrolyte undergoes a significant structural damage during cycling (Li+ intercalation/ deintercalation) process. Also, a bare cathode in contact with liquid electrolyte forms a resistive cathode electrolyte interface (CEI) layer. Both the cathode structure damage and CEI lead to rapid capacity fade [1]. Cathode surface modification has been used to reduce CEI formation and structural damage that in turn improves capacity retention, cycle life, energy density, power density, and safety of a LIB.Recently, the coating of the cathode with an intermediate layer (IL) which is transparent to Li+ conduction but impermeable to electrolyte solvent has been developed to minimize CEI formation and structural damage. IL based on Li+ insulating ceramics such as aluminum oxide (Al2O3), tin oxide (SnO2), and magnesium oxide (MgO) has been developed but to a limited success in mitigating the above cathode degradation. The limited success of Li+ insulating coating relates to limited thickness of coating because resistance of coating layer increases with thickness of IL.To overcome the challenges associated with Li+ insulating IL, recently, Li+ conducting IL (solid-state ceramic electrolytes) has been explored. Some of the most studied ceramic solid electrolytes include lithium niobate (LNO), lithium lanthanum zirconium oxide (LLZO), lithium aluminum titanium phosphate (LATP), etc. Though, LNO (σ = 10-5 mS.cm-1) and LLZO (σ = 10-4 mS.cm-1), LATP (σ = 10-4 mS.cm-1) are better Li+ conductor compared to complete Li+ insulating ILs [2] (Al2O3, MgO, SnO2) but still not adequate for high performance LIB.Lithium aluminum germanium phosphate (LAGP- Li1.5Al0.5Ge1.5(PO4)3 ) has one order higher Li+ conduction (σ = 10-3 S.cm-1) compared to LATP [3]. Thus, we present LIB performance improvement through application of LAGP as IL on lithium cobalt oxide cathode (LCO) (Fig. 1). Figure 1 shows rate capability of LAGP coated LCO vs. pristine LCO, LNO and LLZO coated cathode. We will present a sol-gel as an economical and scalable method to apply LAGP thin-film as IL on LCO. Also, impedance, and storage induced cell degradation will be presented.REFERENCES[1] Joshua P. Pender, Gaurav Jha, Duck Hyun Youn, Joshua M. Ziegler, Ilektra Andoni, Eric J. Choi, Adam Heller, Bruce S. Dunn, Paul S. Weiss, Reginald M. Penner, and C. Buddie Mullins, Electrode Degradation in Lithium-Ion Batteries, ACS Nano 2020, 14, 1243−1295[2] Jeffrey W. Fergus, Ceramic and polymeric solid electrolytes for lithium-ion batteries, Journal of Power Sources195 (2010) 4554–4569[3] B. Kumar, D. Thomas, and J. Kumar, Space-Charge-Mediated Superionic Transport in Lithium Ion Conducting Glass-Ceramics, Journal of The Electrochemical Society, 156(7) A506-A513 (2009)Figure 1. Rate capability test of LCO cathode with LAGP, LNO and LLZO coating. Cathode performance in a half-cell (Li/1MLiPF6/LCO with or without IL) set up. Figure 1

Effects of Plasticizer Content and Ceramic Addition on Electrochemical Properties of Cross-Linked Polymer Electrolyte

The development of a safe electrolyte is the key to improving energy density for next generation lithium batteries. In this work, UV-crosslinked poly(ethylene oxide) (PEO) -based polymer and composite electrolytes are systematically investigated on their ionic conductivity, mechanical and electrochemical properties. The polymer electrolytes are plasticized with non-flammable linear short-chain PEO. In the composite electrolytes, a doped lithium aluminum titanium phosphate (LATP) ceramic, LICGC™, is used as the ceramic filler. It is found that the addition of the plasticizer leads to a tradeoff between ion transport and mechanical properties. In contrast, the addition of ceramic fillers improves both the ionic conductivity and mechanical properties. The sample with 20 wt% of LICGC™ shows a conductivity of ∼0.6 mS cm−1 at 50 °C. This sample also demonstrates much longer cycle life than the neat polymer electrolyte in Li platting/stripping test with a capacity of 1 mAh cm−2. A full cell made with this composite electrolyte against Li metal anode and high voltage LiNi0.6Mn0.2Co0.2O2 cathode shows 94% capacity retention after 30 cycles, compared to 58% capacity retention with the neat polymer electrolyte. These results demonstrate that a hybrid of polymer/ceramic/non-flammable plasticizer is a promising path to high energy density, high voltage lithium batteries.

Influence of lithium phosphate on the structural and lithium-ion conducting properties of lithium aluminum titanium phosphate pellets

Lithium aluminum titanium phosphate (LATP) with a formula of Li1.3Al0.3Ti1.7(PO4)3 has been regarded as one of the most promising inorganic solid-state electrolytes in all-solid-state lithium-ion batteries, and presently, to optimize the structural and electrochemical properties of its ceramic pellets is of crucial importance for potential application purposes. In this paper, chemical lithium phosphate Li3PO4 with a melting point of 837 °C is used as an agglutinant in the ceramics of as-prepared LATP crystallites, aiming to assay its functions in possible performance enhancement. At the sintering temperature of 900 °C, the self-fluxing agglutinant (10.0 wt%) in Li3PO4-LATP composite pellet is expected to fill gaps among close packed particles, and this actually induces an apparent shrinkage in the pellet diameter/thickness, a great decrease in grain-boundary resistance and an obvious increase in total Li+-ion conductivity (e.g., LATP-900 ~ 3.0 × 10−4 S cm−1; Li3PO4-LATP-900 ~ 1.2 × 10−3 S cm−1; at 60 oC). Especially, a polymorphic change of the agglutinant occurring during pellet-sintering process and the in situ formation of ion-conducting interphases may cooperatively explain the improvement of ionic conductivity.