Next-generation Battery Technologies Research Articles

Elucidating the Effect of Planar Graphitic Layers and Cylindrical Pores on the Storage and Diffusion of Li, Na, and K in Carbon Materials

AbstractHard carbons are among the most promising materials for alkali‐ion metal anodes. These materials have a highly complex structure and understanding the metal storage and migration within these structures is of utmost importance for the development of next‐generation battery technologies. The effect of different carbon structural motifs on Li, Na, and K storage and diffusion are probed using density functional theory based on experimental characterizations of hard carbon samples. Two carbon structural models—the planar graphitic layer model and the cylindrical pore model—are constructed guided by small‐angle X‐ray scattering and transmission electron microscopy characterization. The planar graphitic layers with interlayer distance <6.5 Å are beneficial for metal storage, but do not have significant contribution to rapid metal diffusion. Fast diffusion is shown to take place in planar graphitic layers with interlayer distance >6.5 Å, when the graphitic layer separation becomes so wide that there is negligible interaction between the two graphitic layers. The cylindrical pore model, reflecting the curved morphology, does not increase metal storage, but significantly lowers the metal migration barriers. Hence, the curved carbon morphologies are shown to have great importance for battery cycling. These findings provide an atomic‐scale picture of the metal storage and diffusion in these materials.

Selenium sulfide cathode with copper foam interlayer for promising magnesium electrochemistry

Magnesium (Mg) metal anode pairing with Sulfur (S) cathode has been regarded as a promising contender for next-generation battery technology holding the characteristics of safety in use, low cost and high energy density. However, the sluggish kinetic and the inferior reversibility of Mg–S electrochemical reaction are two main challenges impeding the development of practical Mg–S batteries. Herein, SeS2 is proposed as a superior cathode for Mg batteries based on the complementary features of S (high specific capacity) and Se (high electronic conductivity). In this designed Mg–SeS2 battery with a Cu foam interlayer between cathode and separator, SeS2 compositing with ordered mesoporous carbon (SeS2/CMK3) exhibits impressive electrochemical performance. Various characterizations towards the electrochemical evolution on cathode side reveal that Cu foam interlayer not only acts as the trapping layer by the rapid chemical immobilization of polysulfide (polyselenide) species on Cu foam, but also serves as a “promoter” to propel the overall charge-discharge kinetics by the reversible displacement reaction between copper sulfide (copper selenide) and Mg2+. Benefiting from the unique advantages of SeS2/CMK3 and the rationally designed Cu interlayer, this novel Mg–SeS2 system demonstrates a feasible strategy to exploit the rechargeable Mg batteries with low cost, high areal capacity and large current capability.

Co–TiO2 nanoparticles anchored in porous carbon matrix as an efficient sulfur host for lithium/sulfur batteries

Although Lithium/sulfur (Li/S) battery is a promising candidate for the next-generation battery technologies, some serious issues including poor electrical conductivity of sulfur, capacity decay and kinetically sluggish still impede its further development. In this work, Co–TiO2@C composite was prepared via facile impregnation and carbonization of the mixture of Ti-MOF (MIL-125) and Co(NO3)2 as an efficient sulfur host for the Li/S batteries. The composite exhibits a tablet-like structure consisting of porous carbon, on which the TiO2 and Co nanoparticles with the diameter of around 8 nm are uniformly dispersed. The porous carbon matrix and TiO2 nanoparticles can effectively trap polysulfides through physical and chemical adsorption, respectively. Furthermore, the catalytic metal Co accelerates the conversion of adsorbed long-chain lithium polysulfides into short-chain sulfides, resulting in the improvements of reaction kinetics and sulfur utilization. The Co–TiO2@C/sulfur composite shows outstanding electrochemical performance duo to the above synergistic effect. The cell with the composite cathode delivers a high initial specific capacity of 1245 mAh g−1 at a current rate of 0.2C. After 200 cycles, a reversible capacity of 698 mAh g−1 was maintained. The results indicate its great potential for high performance Li/S batteries.

High-Energy-Density Solid-Electrolyte-Based Liquid Li-S and Li-Se Batteries

Summary Lithium-sulfur (Li-S) and Lithium-selenium (Li-Se) batteries are considered as promising candidates for next-generation battery technologies, as they have high energy density and low cost. However, due to the use of a solid Li-metal anode and a liquid organic electrolyte, the current Li-S and Li-Se batteries face several issues in terms of Coulombic efficiency and cycling stability, which seriously impeded their development. Here, we report solid-electrolyte-based liquid Li-S and Li-Se (SELL-S and SELL-Se in short) batteries. The batteries use a Li6.4La3Zr1.4Ta0.6O12 (LLZTO) ceramic tube as electrolyte and work at temperatures higher than the melting point of Li; thus, polysulfide or polyselenide shuttle effects and Li dendrite growth are effectively prevented, and high energy density, together with high stability, fast charge/discharge capability, high Coulombic efficiency, and high energy efficiency, can be achieved. The SELL-S and SELL-Se batteries provide broader platforms for constructing high-energy, high-power, long-lifetime, and low-cost energy storage.

Controlling Electrochemical Lithium Deposition and Sulfur Reduction Mechanism through Liquid Electrolytes

Lithium metal anode has been regarded as the "Holy Grail" of next-generation battery technologies. In order to stabilize the electrodeposited Li metal for safe and high energy batteries, highly concentrated electrolytes (solvate electrolytes) have been proposed to suppress the formation of Li dendritic structure and polysulfide dissolution in lithium-sulfur (Li-S) batteries. (1-5) In this talk, we use in situ transmission X-ray microscopy (TXM) to study the effect of solvate electrolyte on Li plating/stripping process. In situ TXM images show that electrodeposited Li particles with uniform density are formed in solvate electrolyte during initial plating process. The effect of solvate electrolyte on the mechanism of Li growth is studied in detail. Additionally, in situ spectroscopy including Raman and X-ray spectroscopy (X-ray diffraction and X-ray absorption spectroscopy) are used to investigate sulfur reaction mechanism and the interaction between polysulfide and solvate electrolyte. We found that the sulfur species formed in the solvate electrolyte are different from the sulfur species formed in conventional DOL/DME electrolyte. These results suggest that solvate electrolyte changes both polysulfide solubility and sulfur reaction mechanism. We next propose different solvate electrolytes with low polysulfide solubility and high stability toward Li metal to enhance the capacity retention of Li-S batteries.

Assessing Safety Properties of Lithium Metal Batteries

Currently, the so-called all-solid-state battery (ASSB) is getting enormous attention in academia and industry as a potential next-generation battery technology replacing the state-of-the-art lithium ion battery (LIB) based on a liquid electrolyte. Especially the high energy density (Wh/L) and specific energy (Wh/kg) are appealing [1] with regard to the application in electric vehicles and protable devices. However, the breakthrough of the ASSB technology is hindered by practical challenges in terms of processing, rate capability and cycle life. [2] Apart from high energy densities and a long cycle life, significantly enhanced safety properties are considered key for future battery technologies. Therein, the ASSB benefits from the absence of flammable liquid electrolyte as present in state-of-the-art LIBs. However, only very few studies were published showing the evaluation of the safety properties of lithium metal batteries. [3, 4] Therefore, this study aims on giving first insights into the factors influencing the thermal stability, hence the safety properties of different lithium metal battery (LMB) setups. As a baseline, lithium metal batteries based on liquid electrolyte were investigated in order to understand the influence of the lithium metal deposition behavior on the thermal stability of LMBs. Therein, during charging, lithium metal does not deposit homogeneously but forms dendritic or mossy structures often referred to as high surface area lithium (HSAL). [1, 5] At elevated temperatures, the high reactivity of HSAL can lead to fatal consequences, especailly in presence of liquid electrolyte (e.g. fire, explosion). Thus, the controlled deposition of lithium metal is crucial in order to guarantee safe operation of lithium metal batteries. This can be achieved by either modifying the charging process or the lithium metal surface (mechanically/chemically). Beyond that, lithium metal batteries based on either ceramic or polymer-based electrolytes are investigated. Therein, the cells are cycled to different sates of charge (SOC) and/or states of health (SOH) before analyzing the thermal stability by differential scanning calorimetry (DSC). This way, it is possible to determine distinct differences in the onset temperature for exothermic reactions and the evolving heat as a measure for the intensity of the reactions that might lead to a thermal runaway in large-scale cells. Moreover, the thermal stability of the cell components are characterized individually and in presence of each other du deduce interdependencies considering the chemical and thermal stability. In combination with comprehensive post-mortem analysis, it is possible to determine the factors influencing the thermal stability most. In summary, this study presents first results on the thermal stability of various LMB types to unravel the advantages/disadvantages compared to LIBs. [1] T. Placke, et al., J Solid State Electrochem 2017, 21, 1939-1964. [2] K. Kerman, et al., J Electrochem Soc 2017, 164, A1731-A1744. [3] T. Inoue, et al., ACS Appl Mater Interfaces 2017, 9, 1507-1515. [4] Uyama, et al., ACS Appl Energy Mater 2018, 1, 5712-5717. [5] M. Winter, et al., Adv Mater 1998, 10, 725-763.

A New sp2–sp3-Hybridized Metallic Carbon Network for Lithium-Ion Battery Anode with Enhanced Safety and Lithium-Ion Diffusion Rate

Carbon-based materials play a significant role in the development of the next-generation lithium-ion battery technologies. However, the commercial use of anodes has been obstructed by their volume expansion and poor rate performance during the lithiation/delithiation process. Here, by means of first-principles calculations, we identify two hitherto unreported sp2–sp3-hybridized carbon allotropes, D10 and D14 carbon, with space groups Pmma and Pmm2, respectively. Interestingly, D14 carbon is predicted to be metallic with high electron density near the Fermi level. We then demonstrate that this metallic D14 carbon is a possible anode material in lithium-ion batteries: it is found that the energy barrier along the two inequivalent migration paths in D14 carbon is 0.38 (2.28) eV, which is lower than that of the recently reported bco-C16 structure with energy barriers of 0.53 (2.32) eV. Moreover, benefiting from the existence of sp3-hybridized network in D14 carbon, during the process of charging/discharging, ...

(Invited) Modeling at Multiple Scales for Development of Future Energy Storage Technologies

The energy sector is currently undergoing transition, driven by population growth, demand for more and cleaner energy, and increasing customer choice[1]. To facilitate the growth and uptake of renewable energy in a more electrified energy system, developing efficient and economical means of storing and distributing electricity is vital. Next-generation battery technologies and other electrochemical energy storage and conversion technologies have great promise to enable energy transition. Precise control and understanding of electrochemical and other phenomena over multiple length and time scales will play an important role as the energy transition unfolds. Within Shell’s Advanced Energy Storage program, we utilize a framework referred to as Experimental-Modeling Powered Optimization Workflow for Energy StoRage Systems (EMPOWERS). The framework seeks to link phenomena observed at different length scales via experimental and computational means. This talk will share some recent investigation of advanced lithium batteries, with use of DFT, molecular dynamics, and continuum models to investigate advanced battery systems over multiple length and time scales. We will share recent computational investigation into PEO-based polymer systems as electrolytes[2] for lithium metal batteries. We have used molecular dynamics to compute the effect of pressure on key electrolyte parameters, such as density, diffusivity, and transference number. We have also used DFT and ab initio molecular dynamics to study a particular class of cathode material for lithium sulfur batteries. In this case, DFT based on ultrasoft-pseudopotentials was used to calculate the XPS spectra for species present in the cathode in charged and discharged states, which was then validated by experimental XPS data[3]. To complement the electrolyte and electrode-specific component studies, continuum cell models have been used to combine measurements on individual cell components, with an eye towards development of reduced-order models. [1] http://www.shell.com/investorRoyal Dutch Shell PLC, Shell: Energy transitions and portfolio resilience (2016) Royal Dutch Shell PLC, 2016 North America Investor Day (2016) Royal Dutch Shell PLC, Barclays CEO Energy Power Conference (2016) [2] D. T. Hallinan Jr. and N. P. Balsara, Annual Review of Materials Research, 43, 503-525 (2013). [3] Experimental work by Guy Verbist (Shell Global Solutions International B.V.), Alexey Deyko and Christina Christova (Polymer Technology Group Eindhoven (PTG/e) BV.)

(Invited) Electrochemical Fundamentals of Employing Li Metal Anode in the Next-Generation Battery Technologies

To significantly boost the cell-level energy of next-generation battery technologies, one of the most effective approaches is to replace graphite with Li metal which is ultralight but energy concentrated. However, the thermodynamic instability of Li metal leads to many well-known problems that prevent its implementation in realistic batteries. Although many approaches have been proposed to rescue Li metal anodes, most of the work are performed in small-scale coin cells and tested in conditions drastically different from the reality. A full knowledge of Li metal activities at the cell level is lacking but critical for the success of rechargeable Li metal batteries. This talk will discuss the electrochemical fundamentals underlying the formation of Li dendrites which is then correlated to the different Li metal failure mechanisms: cell short or electrolyte/Li depletion. A prototypic Li metal pouch cell with 350 Wh/kg energy has been demonstrated which shows more than 150 stable cycling. A series of fundamentally new insights will be discussed to inspire scientific innovations to take the real challenges of developing future battery technologies.

Effect of Thickness and Surface Decoration of Lithium-Metal Electrodes for Lithium-Metal Batteries

Lithium-metal batteries (LMBs) regained recently increased interest as potential next-generation battery technology besides the lithium ion technology (LIB).[1,2] This originates in the promised enhanced energy density of such batteries when lithium-metal is considered as anode material and also because of the variety of compatible cathode materials, e.g. high voltage lithium transition metal oxide, sulfur and oxygen cathodes. Nevertheless, in laboratory conditions, it is generally accepted that the amount of lithium-metal anode active materials exceeding balanced capacity levels for cathode and anode which are required in practical cells. Such an imbalance is resulting in reduced energy density values. An oversized lithium-metal anode is actually needed due to the heterogeneous lithium electrodeposition and electrodissolution behavior, which results in poor cycling performance, low Coulombic efficiencies, continuous formation of the solid electrolyte interphase (SEI), electrolyte consumption, loss of active material, corrosion and formation of high surface area lithium (HSAL) that leads to dendritic lithium deposits.[3,4] In order to minimize the existing capacity gap between the lithium-metal anode and the cathode materials, thin lithium-metal electrodes (with reduced excess capacity) are required. It has been reported that the amount of capacity used in lithium-metal electrodes has also an effect on the quality (morphology) of the lithium deposits.[5] The surface composition of the lithium-metal electrodes can be adjusted by thinning the surface native film[6] while the interphase to the electrolyte can be tuned by means of an artificial-SEI. The latter approach focuses on creating an artificial-SEI that is able to homogenize the flux of Li-ions during the electrodeposition process resulting in stabilized and enhanced electrochemical performances. In this work, we would like to present the effect that the thickness of the lithium-metal electrodes and artificial-SEI on such electrodes has on the cycling performances of lithium-metal cells. Furthermore, the effect of the different areal capacities, from laboratory grade (>150 µm) to thin lithium foil (<30 µm), and with additional artificial-SEI on the thermal stability of such cells (CR 2032) is also evaluated. Acknowledgements: The work presented here is funded through the Europeans Union's Horizon 2020 research and innovation programme under the Grant Agreement No. 666221 within the HELIS project. The authors also acknowledge the German Federal Ministry of Research and Education (BMBF) for the funding of the project MEET Hi-EnD II (FKZ 03XP0084A).

Ultradispersed WxC nanoparticles enable fast polysulfide interconversion for high-performance Li-S batteries

Li-S batteries are a promising next-generation battery technology but are confronted with a series of fundamental challenges, in particular the notorious shuttle effect of soluble polysulfide intermediates. Current research efforts are mostly focused on designing proper host materials for the entrapment and immobilization of polysulfides. Herein, we demonstrate that electrocatalysis may play an unexpected role in Li-S batteries. Nanosized tungsten carbide particles dispersed on the carbonaceous support are prepared from the pyrolysis of phosphotungstic acid-functionalized metal-organic frameworks. Both experimental measurements and theoretical calculations demonstrate that they not only have strong affinity toward polysulfide intermediates, but also significantly accelerate the reduction of low-order polysulfides that is otherwise kinetically challenged. Using these supported tungsten carbide nanoparticles as the cathode catalyst, our Li-S batteries achieve large capacity, excellent cycling stability and impressive rate capability.

Scalable Synthesis of Size-Controlled Li2S Nanocrystals for Next-Generation Battery Technologies

Lithium sulfide (Li2S) nanocrystals (NCs) are critical materials for emerging solid-state and Li–S battery technologies. Conventional synthesis is energy intensive and costly, and offers limited si...

Insights into the Safety Properties of Lithium Metal Batteries

With regard to current trends, the so-called all-solid-state battery (ASSB) is getting enormous attention in academia and industry as a potential next-generation battery technology replacing the state-of-the-art lithium ion battery (LIB). Especially the high energy density (Wh/L) and specific energy (Wh/kg) are appealing properties of the ASSB [1] potentially enabling longer driving ranges for electric vehicles compared to the state-of-the-art lithium ion technology. However, the breakthrough of the ASSB technology is facing practical challenges in terms of processing, rate capability and cycle life. [2] In addition to high energy densities and a long cycle life, significantly enhanced safety properties are considered key for future battery technologies. Regarding the latter, the ASSB benefits from the absence of flammable liquid electrolyte compared to LIBs. However, only very few studies were published showing the evaluation of the safety properties of lithium metal batteries. [3] Therefore, this study aims on giving first insights into the factors influencing the thermal stability, hence the safety properties of different lithium metal battery setups. As a starting point, lithium metal batteries based on liquid electrolyte were investigated in order to understand the influence of the lithium metal deposition behavior on the thermal stability of the cell. Therein, it has to be considered that during charging lithium metal does not deposit homogeneously but forms dendritic or mossy structures often referred to as high surface area lithium (HSAL). [1, 4] At elevated temperatures, the high reactivity of HSAL in presence of liquid electrolyte can lead to fatal consequences (e.g. fire, explosion). Thus, the controlled deposition of lithium metal is crucial in order to guarantee safe operation of lithium metal batteries. This can be achieved by either modifying the charging process or the lithium metal surface (mechanically/chemically). Beyond that, lithium metal batteries based on either ceramic or polymer-based electrolytes are investigated. Therein, the cells are cycled to different sates of charge (SOC) and/or states of health (SOH) before analyzing the thermal stability by differential scanning calorimetry (DSC). This way, it is possible to determine distinct differences in the onset temperature for exothermic reactions and the evolving heat as a measure for the intensity of the reactions that might lead to a thermal runaway in large-scale cells. Moreover, the thermal stability of the cell components are characterized individually and in presence of each other. In combination with comprehensive post-mortem analysis, it is possible to determine the factors influencing the thermal stability most. In summary, this study presents first results on the thermal stability of various lithium metal battery types to unravel the advantages/disadvantages compared to LIBs. The authors acknowledge the BMBF for funding the project “BCT” (03XP019I). [1] T. Placke, et al., J Solid State Electrochem 2017, 21, 1939-1964. [2] K. Kerman, et al., J Electrochem Soc 2017, 164, A1731-A1744. [3] T. Inoue, et al., ACS Appl Mater Interfaces 2017, 9, 1507-1515. [4] M. Winter, et al., Adv Mater 1998, 10, 725-763.

Beyond Intercalation Chemistry for Rechargeable Mg Batteries: A Short Review and Perspective.

Rechargeable magnesium (Mg) batteries are an attractive candidate for next-generation battery technology because of their potential to offer high energy density, low cost, and safe use. Despite recent substantial progress achieved in the development of efficient electrolytes, identifying high-performance cathode materials remains a bottleneck for the realization of practical Mg batteries. Due to the strong interaction between the doubly charged Mg2+ ions and the host matrix, most of the conventional intercalation cathodes suffer from low capacity, high voltage hysteresis, and low energy density in Mg based battery systems. Alternatively, the thermodynamically favorable conversion reaction may circumvent the sluggish Mg2+ diffusion kinetics. In this review, the focus will be laid on promising cathodes beyond the typical intercalation-type materials. We will give an overview of the recent emerging Mg systems with conversion-type and organic cathodes.

Fast kinetics of multivalent intercalation chemistry enabled by solvated magnesium-ions into self-established metallic layered materials

Rechargeable magnesium batteries are one of the most promising candidates for next-generation battery technologies. Despite recent significant progress in the development of efficient electrolytes, an on-going challenge for realization of rechargeable magnesium batteries remains to overcome the sluggish kinetics caused by the strong interaction between double charged magnesium-ions and the intercalation host. Herein, we report that a magnesium battery chemistry with fast intercalation kinetics in the layered molybdenum disulfide structures can be enabled by using solvated magnesium-ions ([Mg(DME)x]2+). Our study demonstrates that the high charge density of magnesium-ion may be mitigated through dimethoxyethane solvation, which avoids the sluggish desolvation process at the cathode-electrolyte interfaces and reduces the trapping force of the cathode lattice to the cations, facilitating magnesium-ion diffusion. The concept of using solvation effect could be a general and effective route to tackle the sluggish intercalation kinetics of magnesium-ions, which can potentially be extended to other host structures.

Atomic-Scale Observation of Electrochemically Reversible Phase Transformations in SnSe2 Single Crystals.

2D materials have shown great promise to advance next-generation lithium-ion battery technology. Specifically, tin-based chalcogenides have attracted widespread attention because lithium insertion can introduce phase transformations via three types of reactions-intercalation, conversion, and alloying-but the corresponding structural changes throughout these processes, and whether they are reversible, are not fully understood. Here, the first real-time and atomic-scale observation of reversible phase transformations is reported during the lithiation and delithiation of SnSe2 single crystals, using in situ high-resolution transmission electron microscopy complemented by first-principles calculations. Lithiation proceeds sequentially through intercalation, conversion, and alloying reactions (SnSe2 → Lix SnSe2 → Li2 Se + Sn → Li2 Se + Li17 Sn4 ) in a manner that maintains structural and crystallographic integrity, whereas delithiation forms numerous well-aligned SnSe2 nanodomains via a homogeneous deconversion process, but gradually loses the coherent orientation in subsequent cycling. Furthermore, alloying and dealloying reactions cause dramatic structural reorganization and thereby consequently reduce structural stability and electrochemical cyclability, which implies that deep discharge for Sn chalcogenide electrodes should be avoided. Overall, the findings elucidate atomistic lithiation and delithiation mechanisms in SnSe2 with potential implications for the broader class of 2D metal chalcogenides.

Mechanism Study on the Interfacial Stability of a Lithium Garnet-Type Oxide Electrolyte against Cathode Materials

All-solid-state lithium-ion battery is considered to be one of the most promising next-generation battery technologies. Understanding the interfacial evolution of a solid electrolyte and a cathode electrode during mixing and sintering is of great importance and can provide guidance to avoid forming unwanted compounds and decrease the interfacial resistance. In this work, chemical compatibilities are investigated between a Ta-doped Li7La3Zr2O12 (LLZO) solid electrolyte and major commercial metal-oxide cathodes LiCoO2 (LCO) and Li(NiCoMn)1/3O2 (NCM) through ball-milling and cosintering processes. As revealed by X-ray absorption spectroscopy and transmission electron microscopy, LLZO spontaneously covers the majority of the large LCO and NCM particles with a thickness of ∼100 nm after ball milling. The thickness of LLZO layer on these cathodes decreases to about 10 nm after cosintering at 873 K, and an interfacial layer of approximately 3 nm is observed for NCM/LLZO. LCO shows a higher thermal stability than...

Frontiers of solid-state batteries

Abstract

(Invited) Reactions or No Reaction: Lithium Deposition on the Surface of Solid State Electrolyte

Li metal anode has regained intensive interest in recent years in order to develop high energy next-generation battery technologies. Unfortunately, Li metal suffers from poor cycling stability and low efficiency as well as the formation of dangerous Li dendrites raising safety concerns. The employment of solid state electrolyte (SSE) to prevent Li dendrite growth provides a promising approach to address the dendrite issue. However, recent studies indicate that Li dendrites easily form at elevated current densities, while the fundamental mechanisms of forming Li dendrites within SSE is still unknown. This calls for further investigation to understand, and control the detrimental observation. The origin and evolution of Li dendrite growth through SSE will be discussed in this talk by using two different SSE membranes, garnet and phosphate-type, as the separators. During cycling, Li is repeatedly deposited on SSE. Although a good SSE should not react with the deposited Li, the reactions between Li deposits and SSE generate a self-terminating interface, which stops the fast propagation of dendritic Li through the SSE membrane. New insights are provided on the further modification and/or incorporation of interfacial layers between SSE and Li metal to enable future solid state batteries.

High-Performance All-Solid-State Na-S Battery Enabled by Casting-Annealing Technology.

Room-temperature all-solid-state Na-S batteries (ASNSBs) using sulfide solid electrolytes are a promising next-generation battery technology due to the high energy, enhanced safety, and earth abundant resources of both sodium and sulfur. Currently, the sulfide electrolyte ASNSBs are fabricated by a simple cold-pressing process leaving with high residential stress. Even worse, the large volume change of S/Na2S during charge/discharge cycles induces additional stress, seriously weakening the less-contacted interfaces among the solid electrolyte, active materials, and the electron conductive agent that are formed in the cold-pressing process. The high and continuous increase of the interface resistance hindered its practical application. Herein, we significantly reduce the interface resistance and eliminate the residential stress in Na2S cathodes by fabricating Na2S-Na3PS4-CMK-3 nanocomposites using melting-casting followed by stress-release annealing-precipitation process. The casting-annealing process guarantees the close contact between the Na3PS4 solid electrolyte and the CMK-3 mesoporous carbon in mixed ionic/electronic conductive matrix, while the in situ precipitated Na2S active species from the solid electrolyte during the annealing process guarantees the interfacial contact among these three subcomponents without residential stress, which greatly reduces the interfacial resistance and enhances the electrochemical performance. The in situ synthesized Na2S-Na3PS4-CMK-3 composite cathode delivers a stable and highly reversible capacity of 810 mAh/g at 50 mA/g for 50 cycles at 60 °C. The present casting-annealing strategy should provide opportunities for the advancement of mechanically robust and high-performance next-generation ASNSBs.