Li3PS4 Research Articles

In Situ Analysis of Interfacial Morphological and Chemical Evolution in All-Solid-State Lithium-Metal Batteries.

In situ analysis of Li plating/stripping processes and evolution of solid electrolyte interphase (SEI) are critical for optimizing all-solid-state Li metal batteries (ASSLMB). However, the buried solid-solid interfaces present a challenge for detection which preclude the employment of multiple analysis techniques. Herein, by employing complementary in situ characterizations, morphological/chemical evolution, Li plating/stripping dynamics and SEI dynamics were directly detected. As a mixed ionic-electronic conducting interface, Li|Li10GeP2S12 (LGPS) performed distinct interfacial morphological/chemical evolution and dynamics from ionic-conducting/electronic-isolating interface like Li|Li3PS4 (LPS), which were revealed by combination of in situ atomic force microscopy and in situ X-ray photoelectron spectroscopy. Though Li plating speed in LGPS was higher than LPS, speed of SSE decomposition was similar and ~85 % interfacial SSE turned into SEI during plating and remained unchanged in stripping. To leverage strengths of different SSEs, an LPS-LGPS-LPS sandwich electrolyte was developed, demonstrating enhanced ionic conductivity and improved interfacial stability with less SSE decomposition (25 %). Using in situ Kelvin probe force microscopy, Li-ion behavior at interface between different SSEs was effectively visualized, uncovering distribution of Li ions at LGPS|LPS interface under different potentials.

In Situ Analysis of Interfacial Morphological and Chemical Evolution in All‐Solid‐State Lithium‐Metal Batteries

AbstractIn situ analysis of Li plating/stripping processes and evolution of solid electrolyte interphase (SEI) are critical for optimizing all‐solid‐state Li metal batteries (ASSLMB). However, the buried solid‐solid interfaces present a challenge for detection which preclude the employment of multiple analysis techniques. Herein, by employing complementary in situ characterizations, morphological/chemical evolution, Li plating/stripping dynamics and SEI dynamics were directly detected. As a mixed ionic‐electronic conducting interface, Li|Li10GeP2S12 (LGPS) performed distinct interfacial morphological/chemical evolution and dynamics from ionic‐conducting/electronic‐isolating interface like Li|Li3PS4 (LPS), which were revealed by combination of in situ atomic force microscopy and in situ X‐ray photoelectron spectroscopy. Though Li plating speed in LGPS was higher than LPS, speed of SSE decomposition was similar and ~85 % interfacial SSE turned into SEI during plating and remained unchanged in stripping. To leverage strengths of different SSEs, an LPS‐LGPS‐LPS sandwich electrolyte was developed, demonstrating enhanced ionic conductivity and improved interfacial stability with less SSE decomposition (25 %). Using in situ Kelvin probe force microscopy, Li‐ion behavior at interface between different SSEs was effectively visualized, uncovering distribution of Li ions at LGPS|LPS interface under different potentials.

Integrated Dual‐Phase Ion Transport Design Within Electrode for Fast‐Charging Lithium‐Ion Batteries

AbstractThe development of fast‐charging lithium‐ion batteries with high energy density is hindered by the sluggish Li+ transport and substantial polarization within graphite electrodes. Herein, this study proposes that the integrated design of liquid electrolyte and solid electrolyte, a dual‐phase electrolyte (DP‐electrolyte), can facilitate Li+ transport within a thick electrode. A 3D Li3PS4 (LPS) network is constructed within the graphite electrode to form the LPS/graphite electrode. This is achieved through the in situ conversion of the P4S16 into the LPS, a process introduced during the slurry processing. Both experimental findings and simulation outcomes indicate that this design mitigates the concentration polarization due to the improved Li+ transport capability with an overall high Li+ transference number within the electrode. With a high capacity of ≈3.1 mAh cm−2 attributed to the graphite electrode, the LiNi0.6Co0.2Mn0.2O2 (NCM622)||LPS/graphite cells demonstrate superior fast‐charging capability (4 C, 15 min, charging to ≈87.7%) and stable cycling performance (4 C, 700 cycles, ≈80% capacity retention). Furthermore, they exhibit commendable low‐temperature performance. The Ah‐level pouch cell achieves 87.5% recharge in 15 min with an energy density of ≈221.5 Wh kg−1. This work offers an alternative avenue for the advancement of fast‐charging lithium‐ion batteries with practical high energy density.

Effect of reaction temperature and impact force on formation and particle shape of β-Li3PS4 in liquid phase synthesis

All-solid-state lithium-ion batteries are promising next-generation secondary batteries, primarily due to their superior safety. In their production process, it is necessary to achieve large contact interfaces between the particles and improve particle fluidity. The particle shape of the solid electrolyte plays a key role in addressing these requirements. Li3PS4 (LPS) is synthesized in the liquid phase and offers the advantages of cost-effectiveness and production-scalability. However, the mechanisms controlling the particle size and shape have not yet been revealed. In this study, we synthesized LPS particles in the liquid phase using a hot stirrer and an ultrasonic homogenizer to investigate the effects of reaction temperature and impact force on the reaction rate and particle shape. We successfully synthesized shape-controlled particles with high ionic conductivity by combining different synthesis methods. This study provides valuable data for optimizing the synthesis conditions to attain specific particle shapes and sizes.

Effect of Mixing Intensity on Electrochemical Performance of Oxide/Sulfide Composite Electrolytes

Despite the variety of solid electrolytes available, no single solid electrolyte has been found that meets all the requirements of the successor technology of lithium-ion batteries in an optimum way. However, composite hybrid electrolytes that combine the desired properties such as high ionic conductivity or stability against lithium are promising. The addition of conductive oxide fillers to sulfide solid electrolytes has been reported to increase ionic conductivity and improve stability relative to the individual electrolytes, but the influence of the mixing process to create composite electrolytes has not been investigated. Here, we investigate Li3PS4 (LPS) and Li7La3Zr2O12 (LLZO) composite electrolytes using electrochemical impedance spectroscopy and distribution of relaxation times. The distinction between sulfide bulk and grain boundary polarization processes is possible with the methods used at temperatures below 10 °C. We propose lithium transport through the space-charge layer within the sulfide electrolyte, which increases the conductivity. With increasing mixing intensities in a high-energy ball mill, we show an overlay of the enhanced lithium-ion transport with the structural change of the sulfide matrix component, which increases the ionic conductivity of LPS from 4.1 × 10−5 S cm−1 to 1.7 × 10−4 S cm−1.

Impact of Processing Methodology on the Performance of Hybrid Sulfide-Polymer Solid State Electrolytes for Lithium Metal Batteries

Abstract Hybrid sulfide-polymer composite electrolytes are promising candidates for enabling lithium metal batteries because of their high ionic conductivity and flexibility. These composite materials are primarily prepared through solution casting methods to obtain a homogenous distribution of polymer within the inorganic. However, little is known about the influence of the morphology of the polymer and of the inorganic on the ionic conductivity and electrochemical behavior of these hybrid systems. In this study, we assessed the impact of processing methodology, either solution processing or solvent-free ball milling, on overall performance of hybrid electrolytes containing amorphous Li3PS4 (LPS) and non-reactive polyethylene. We demonstrate that using even non-polar, non-reactive solvents can alter the LPS crystalline structure, leading to a lower ionic conductivity. Additionally, we show that ball milling leads to a non-homogenous distribution of polymer within the inorganic, which leads to a higher ionic conductivity than samples processed via solution casting. Our work demonstrates that the morphology of the polymer and the sulfide plays a key role in the ionic conductivity and subsequent electrochemical stability of these hybrid electrolytes.

Tracking Li atoms in real-time with ultra-fast NMR simulations.

We present for the first time a multiscale machine learning approach to jointly simulate atomic structure and dynamics with the corresponding solid state Nuclear Magnetic Resonance (ssNMR) observables. We study the use-case of spin-alignment echo (SAE) NMR for exploring Li-ion diffusion within the solid state electrolyte material Li3PS4 (LPS) by calculating quadrupolar frequencies of 7Li. SAE NMR probes long-range dynamics down to microsecond-timescale hopping processes. Therefore only a few machine learning force field schemes are able to capture the time- and length scales required for accurate comparison with experimental results. By using a new class of machine learning interatomic potentials, known as ultra-fast potentials (UFPs), we are able to efficiently access timescales beyond the microsecond regime. In tandem, we have developed a machine learning model for predicting the full 7Li electric field gradient (EFG) tensors in LPS. By combining the long timescale trajectories from the UFP with our model for 7Li EFG tensors, we are able to extract the autocorrelation function (ACF) for 7Li quadrupolar frequencies during Li diffusion. We extract the decay constants from the ACF for both crystalline β-LPS and amorphous LPS, and find that the predicted Li hopping rates are on the same order of magnitude as those predicted from the Li dynamics. This demonstrates the potential for machine learning to finally make predictions on experimentally relevant timescales and temperatures, and opens a new avenue of NMR crystallography: using machine learning dynamical NMR simulations for accessing polycrystalline and glass ceramic materials.

Reducing Gases Triggered Cathode Surface Reconstruction for Stable Cathode-Electrolyte Interface in Practical All-Solid-State Lithium Batteries.

The interfacial compatibility between cathodes and sulfide solid-electrolytes (SEs) is a critical limiting factor of electrochemical performance in all-solid-state lithium-ion batteries (ASSLBs). This work presents a gas-solid interface reduction reaction (GSIRR), aiming to mitigate the reactivity of surface oxygen by inducing a surface reconstruction layer (SRL) . The application of a SRL, CoO/Li2 CO3 , onto LiCoO2 (LCO) cathode results in impressive outcomes, including high capacity (149.7 mAh g-1 ), remarkable cyclability (retention of 84.63% over 400 cycles at 0.2 C), outstanding rate capability (86.1 mAh g-1 at 2 C), and exceptional stability in high-loading cathode (28.97 and 23.45mg cm-2 ) within ASSLBs. Furthermore, the SRL CoO/Li2 CO3 enhances the interfacial stability between LCO and Li10 GeP2 S12 as well as Li3 PS4 SEs. Significantly, the experiments suggest that the GSIRR mechanism can be broadly applied, not only to LCO cathodes but also to LiNi0.8 Co0.1 Mn0.1 O2 cathodes and other reducing gases such as H2 S and CO, indicating its practical universality. This study highlights the significant influence of the surface chemistry of the oxide cathode on interfacial compatibility, and introduces a surface reconstruction strategy based on the GSIRR process as a promising avenue for designing enhanced ASSLBs.

A Ternary (P, Se, S) Covalent Inorganic Framework as a Shuttle Effect-Free Cathode for Li-S Batteries.

Developing new cathode materials to avoid shuttle effect of Li-S batteries at source is crucial for practical high-energy applications, which, however, remains a great challenge. Herein, a new class of sulfur-containing ternary covalent inorganic framework (CIF), P4 Se6 S40 , is explored, by simply comelting powders of P, S, and Se. The P4 Se6 S40 CIF with open framework enables all active sites available during electrochemical reactions, giving a high capacity delivery. Moreover, introducing Se atoms can improve intrinsic electronic conductivity of S chains yet without remarkably compromising the capacity because Se is also electrochemical active to lithium storage. More importantly, Se atoms in S-Se chains can serve as a heteroatom barrier to block the bonding of S atoms around, effectively avoiding the formation of long-chain polysulfides during cycling. Besides, stable Li3 PS4 with a tetrahedral configuration formed after lithiation works as not only a good ionic conductor to promote Li ion diffusion, but a three-dimensional spatial barrier and chemical anchor to suppress the dissolution and diffusion of lithium polysulfides (LiPS), further inhibiting the shuttle effect. Consequently, the P4 Se6 S40 cathode delivers high capacity and excellent capacity retention with even a high loading of 10.5 mg cm-2 which far surpasses the requirement for commercial applications.

Investigating the Production Atmosphere for Sulfide-Based Electrolyte Layers Regarding Occupational Health and Safety

In all-solid-state battery (ASSB) research, the importance of sulfide electrolytes is steadily increasing. However, several challenges arise concerning the future mass production of this class of electrolytes. Among others, the high reactivity with atmospheric moisture forming toxic and corrosive hydrogen sulfide (H2S) is a major issue. On a production scale, excessive exposure to H2S leads to serious damage of production workers’ health, so additional occupational health and safety measures are required. This paper investigates the environmental conditions for the commercial fabrication of slurry-based sulfide solid electrolyte layers made of Li3PS4 (LPS) and Li10GeP2S12 (LGPS) for ASSBs. First, the identification of sequential production steps and processing stages in electrolyte layer production is carried out. An experimental setup is used to determine the H2S release of intermediates under different atmospheric conditions in the production chain, representative for the production steps. The H2S release rates obtained on a laboratory scale are then scaled up to mass production dimensions and compared to occupational health and safety limits for protection against H2S. It is shown that, under the assumptions made for the production of a slurry-based electrolyte layer with LPS or LGPS, a dry room with a dew point of τ=−40 ∘C and an air exchange rate of AER=30 1h is sufficient to protect production workers from health hazards caused by H2S. However, the synthesis of electrolytes requires an inert gas atmosphere, as the H2S release rates are much higher compared to layer production.

Mechano-chemical solution process for Li3PS4 solid electrolyte using dibromomethane for enhanced conductivity and cyclability in all-solid-state batteries

Increasing conductivity and stability is one of the essential and ultimate goals for electrolyte research. For sulfide solid-state electrolytes (SSEs), elemental doping is often suggested for this purpose. A typical doping method for sulfide SSE is an energy intensive and non-uniform solid-state reaction, because most solvents react with sulfide SSEs. Here, we have demonstrated that highly efficient Br-doping into lithium thiophosphate Li3PS4 (LPS) can be achieved through a solution-based strategy using dibromomethane (DBM) as Br-source and solvent in a ball-milling process. In this “mechano-chemical” process, simultaneous pulverization of large LPS particles and Br-doping occur, achieving remarkably improved Li+ ion conductivity (1.3 mS cm−1) which is eight times higher than that of the pristine LPS at only 1.14 at. % Br doping. This conductivity is one of the highest for LPS SSE, especially at this low doping level. The LPS to DBM ratio critically affects the efficiency of these chemical and physical modifications. In all-solid-state lithium-metal-batteries, the modified LPS exhibited exceptional cycling stability with reduced overpotential. The Li-Li symmetric cell demonstrated extremely stable Li deposition and stripping for over 1350 h, and the full cell with the Li anode and Li[Ni0.8Co0.1Mn0.1]O2 cathode retained 83 % of its initial capacity after 100 cycles. With possible application toward the slurry fabrication of LPS SSEs, the proposed approach provides a new and effective strategy for fabricating high-performance sulfide SSEs for large-scale applications.

Design Strategies of Li-Si Alloy Anode for Mitigating Chemo-Mechanical Degradation in Sulfide-Based All-Solid-State Batteries.

Composite anodes of Li3 PS4 glass+Li-Si alloy (Type 1) and Li3 N+LiF+Li-Si alloy (Type 2) are prepared for all-solid-state batteries with Li3 PS4 (LPS) glass electrolyte and sulfur/LPS glass/carbon composite cathode. Using a three-electrode system, the anode and cathode potentials are separated, and their polarization resistances are individually traced. Even under high-cutoff-voltage conditions (3.7V), Type 1and 2cells are stably cycled without voltage noise for >200cycles. Although cathode polarization resistance drastically increases after 3.7V charge owing to LPS oxidation, LPS redox behavior is fairly reversible upon discharge-charge unlike the non-composite alloy anode cell. Time-of-flight secondary ion mass spectrometry analysis reveals that the enhanced cyclability is attributed to uniform Li-Si alloying throughout the composite anode, providing more pathways for lithium ions even when these ions are over-supplied via LPS oxidation. These results imply that LPS-based cells can be reversibly cycled with LPS redox even under high-cutoff voltages, as long as non-uniform alloying (lithium dendrite growth) is prevented. Type 1and 2cells exhibit similar performance and stability although reduction product is formed in Type 1. This work highlights the importance of alloy anode design to prevent chemo-mechanical failure when cycling the cell outside the electrochemical stability window.

Particle size control of cathode components for high‐performance all‐solid‐state lithium–sulfur batteries

AbstractUnderstanding the size effect of each component on battery performance is essential for designing high‐performance Li2S/S cathode for all‐solid‐state Li–S batteries. However, the size effects of different components are always coupled because ball‐milling, an indispensable process to synthesize reversible cathode, simultaneously and uncontrollably reduces the particle size of all the components. Here, a liquid‐phase method, without ball‐milling, is developed to synthesize the Li2S composite cathode, so that the particle size of the active material Li2S and the solid electrolyte Li3PS4 (LPS) can be independently controlled at nano‐ or microscale. This helps reveal that compositing Li2S and the conductive agent at nanoscale is essential for enhancing the reaction kinetics, whereas the nanoscale particle size and homogenous distribution of LPS is important for accommodating the large volume change of the cathode. By reducing the particle size of Li2S to 9.4 nm and that of LPS to 44 nm, the liquid‐phase‐synthesized composite cathode exhibits reversible capacity and 100% utilization of Li2S under 0.1 C rate.

Tin Interlayer at the Li/Li3PS4 Interface for Improved Li Stripping/Plating Performance

Li metal is a promising negative electrode material for the development of all-solid-state batteries with high energy densities. However, the short-circuiting of batteries owing to Li dendrite formation is challenging. To solve this issue, it is crucial to form a suitable interface between the Li metal and solid electrolyte. This study demonstrates that the incorporation of a Sn interlayer at the interface between the Li metal and Li3PS4 (LPS) electrolyte improved the Li stripping/plating performance of all-solid-state Li symmetrical cells. The cycling performance was further enhanced by replacing pure Li metal with a Li–Mg alloy. Galvanostatic cycling tests were conducted on a symmetrical cell of Li–Mg/Sn/LPS/Sn/Li–Mg at a current density of 1.0 mA cm–2 and a temperature of 100 °C. The operation of the cell was stable for 5000 h without short-circuiting. X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that Sn film incorporation into the Li or Li–Mg/LPS interface suppressed the reductive LPS decomposition and maintained a stable interface. These findings will facilitate the development of interfacial modifications between Li metal and sulfide solid electrolytes to enhance the cycling performance of all-solid-state Li metal batteries.

Disentangling Phase and Morphological Evolution During the Formation of the Lithium Superionic Conductor Li10 GeP2 S12.

The structural and morphological changes of the Lithium superionic conductor Li10 GeP2 S12 , prepared via a widely used ball milling-heating method over a comprehensive heat treatment range (50-700 °C), are investigated. Based on the phase composition, the formation process can be distinctly separated into four zones: Educt, Intermediary, Formation, and Decomposition zone. It is found that instead of Li4 GeS4 -Li3 PS4 binary crystallization process, diversified intermediate phases, including GeS2 in different space groups, multiphasic lithium phosphosulfides (Lix Py Sz ), and cubic Li7 Ge3 PS12 phase, are involved additionally during the formation and decomposition of Li10 GeP2 S12 . Furthermore, the phase composition at temperatures around the transition temperatures of different formation zones shows a significant deviation. At 600 °C, Li10 GeP2 S12 is fully crystalline, while the sample decomposed to complex phases at 650 °C with 30wt.% impurities, including 20wt.% amorphous phases. These findings over such a wide temperature range are first reported and may help provide previously lacking insights into the formation and crystallinity control of Li10 GeP2 S12 .

Local lattice structures and electronic properties of β-Li3PS4/CuS interface

In all-solid-state lithium–sulfur batteries (ASSLBs), unfavorable solid–solid contact at the interfaces with sulfide electrolyte (SE) is one of the important reasons affecting the properties of ASSLBs. CuS is a promising cathode material, and [Formula: see text]-Li3PS4 (LPS) is a newly found SE used for ASSLBs. In order to deeply explore the electronic properties at the interface between these two materials, we used the first-principles calculation method to investigate the local lattice structures, electronic properties, work-function, and charge distribution of LPS/CuS interface. The interface binding energy of the LPS/CuS interface is about −0.568 J/m2. Hence, the LPS/CuS interface structure is thermodynamically reasonable and stable with newly formed chemical bonds at the interface. The interfacial electron density of state shows the metallic properties, which are mainly contributed by Cu-[Formula: see text], [Formula: see text] orbitals and S-[Formula: see text], [Formula: see text] orbitals in CuS and S-[Formula: see text] orbital electrons in LPS. Furthermore, the work function of the interface means the formation of a space charge layer, which has a certain influence on the charge and discharging process.

Long-Life Lithium-Metal All-Solid-State Batteries and Stable Li Plating Enabled by InSitu Formation of Li3 PS4 in the SEI Layer.

An ultrastable and kinetically favorable interface is constructed between sulfide-poly(ethylene oxide) (PEO) composite solid electrolytes (CSEs) and lithium metal, via insitu formation of a solid electrolyte interphase (SEI) layer containing Li3 PS4 . A speciallydesigned sulfide, lithium polysulfidophosphate (LPS), can distribute uniformly in the PEO matrix via a simple stirring process because of its complete solubility in acetonitrile solvent, which is advantageous for creating a homogeneous SEI layer. The CSE/Li interface with high Li+ transportation capability is stabilized quickly through insitu formation of a Li3 PS4 /Li2 S/LiF layer via the reaction between LPS and lithium metal to inhibit lithium dendrite growth. A Li/Li symmetric cell with the LPS-integrated CSE exhibits constant and small CSE/Li resistance of 10Ωcm2 during cycling, delivering stable cycling for 3475h at a current density of 0.2mAcm-2 and a high critical current density of 0.9mAcm-2 at 60°C. Impressive electrochemical performance is also demonstrated for LiFePO4 /CSE/Li all-solid-state batteries with capacity of 127.6mAhg-1 after 1000cycles at 1C.

Structure and Property Changes in Sulfide Solid Electrolytes with Lithiation: A First-Principles Study

Sulfide-based lithium-ion conductors such as Li3PS4 (LPS) and Li10GeP2S12 (LGPS) have received considerable attention for use as solid electrolytes for rechargeable batteries because of their high ionic conductivity, wide electrochemical window, and appropriate mechanical properties. However, their wide application in all-solid-state lithium batteries is hindered by spontaneous decomposition and solid electrolyte interphase layer formation when in contact with Li metal. To better understand the structure and property changes of LPS and LGPS with lithiation, we have systematically analyzed lithiated LPS/LGPS with varying Li contents by calculating their structural, electronic, and mechanical properties with density functional theory. The variation of Li-ion conductivity in these materials with the lithiation degree is also evaluated using ab initio molecular dynamic simulations. Our results unequivocally show that Li incorporation leads to decomposition of PS4 3- and GeS4 4- tetrahedra, resulting in the formation of small P and GeP clusters, along with Li2S production. The P and GeP clusters are eventually converted to Li3P and Li15Ge4 when LPS and LGPS are fully lithiated. The structural evolution gives rise to volume expansion and band gap narrowing. Over-lithiated LPS/LGPS tends to show metallic character, which could be partly responsible for the electrolyte failure. Despite the significant structural changes, the Li ion diffusivity and conductivity in both LPS and LGPS remain at the same order of the magnitude. This work provides a better understanding of the reaction behavior of LPS and LGPS with Li metal and also insight into how to analyze the reaction at the Li metal/sulfide electrolyte interface leading to an inorganic interphase layer.

Interfaces between Ceramic and Polymer Electrolytes: A Comparison of Oxide and Sulfide Solid Electrolytes for Hybrid Solid-State Batteries

Hybrid solid-state batteries using a bilayer of ceramic and solid polymer electrolytes may offer advantages over using a single type of solid electrolyte alone. However, the impedance to Li+ transport across interfaces between different electrolytes can be high. It is important to determine the resistance to Li+ transport across these heteroionic interfaces, as well as to understand the underlying causes of these resistances; in particular, whether chemical interphase formation contributes to giving high resistances, as in the case of ceramic/liquid electrolyte interfaces. In this work, two ceramic electrolytes, Li3PS4 (LPS) and Li6.5La3Zr1.5Ta0.5O12 (LLZTO), were interfaced with the solid polymer electrolyte PEO10:LiTFSI and the interfacial resistances were determined by impedance spectroscopy. The LLZTO/polymer interfacial resistance was found to be prohibitively high but, in contrast, a low resistance was observed at the LPS/polymer interface that became negligible at a moderately elevated temperature of 50 °C. Chemical characterization of the two interfaces was carried out, using depth-profiled X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry, to determine whether the interfacial resistance was correlated with the formation of an interphase. Interestingly, no interphase was observed at the higher resistance LLZTO/polymer interface, whereas LPS was observed to react with the polymer electrolyte to form an interphase.

Size control of sulfide-based solid electrolyte particles through liquid-phase synthesis

All-solid-state lithium-ion batteries (ASS-LiB) have garnered attention as the next-generation secondary batteries owing to their high safety and energy densities. The ASS-LiBs are composed of inorganic solid electrolytes, instead of an organic liquid electrolyte. Therefore, interstitial voids deteriorate the battery capacity, which is a serious problem with ASS-LiBs. A straightforward solution to this problem is to fill the voids using smaller particles. However, the particle size control is yet to be established, and there are insufficient studies on particle size control. In this study, nano-sized solid electrolyte particles of Li3PS4 (LPS), which is a typical sulfide solid electrolyte, was synthesized using a liquid-phase shaking method. The nucleation rate of LPS was improved using the submicron-sized Li2S as raw material, which was prepared through wet milling and dissolution-precipitation processes. Consequently, the liquid-phase shaking method with fine Li2S powder was successfully used to synthesize the nano-sized LPS particles with high ionic conductivity.