Deeply Lithiated Carbonaceous Materials for Great Lithium Metal Protection in All-Solid-State Batteries.

Protection of lithium (Li) metal electrode is a core challenge for all-solid-state Li metal batteries (ASSLMBs). Carbon materials with variant structures have shown great effect of Li protection in liquid electrolytes, however, can accelerate the solid-state electrolyte (SE) decomposition owing to the high electronic conductivity, seriously limiting their application in ASSLMBs. Here, a novel strategy is proposed to tailor the carbon materials for efficient Li protection in ASSLMBs, by in situ forming a rational niobium-based Li-rich disordered rock salt (DRS) shell on the carbon materials, providing a favorable percolating Li+ diffusion network for speeding the carbon lithiation, and enabling simultaneously improved lithiophilicity and reduced electronic conductivity of the carbon structure at deep lithiation state. Using the proposed strategy, different carbon materials, such as graphitic carbon paper and carbon nanotubes, are tailored with great ability to speed the interfacial kinetics, homogenize the Li plating/stripping processes, and suppress the SE decompositions, enabling much improved performances of ASSLMBs under various conditions approaching the practical application. This strategy is expected to create a novel roadmap of Li protection for developing reliable high-energy-density ASSLMBs.

Niobium sulfide nanocomposites as cathode materials for all-solid-state lithium batteries with enhanced electrochemical performance.

All-solid-state lithium batteries coupled with transition metal sulfide cathodes have gained significant attention due to their high energy density and exceptional safety. However, there are still critical challenges impeding their practical application, such as limited capacity delivery, weak ionic reaction kinetics and volume expansion. Herein, an a-NbS4/20%VGCF@15%Li7P3S11 nanocomposite cathode material is employed in all-solid-state batteries. A certain proportion of VGCF is introduced into crystalline NbS4 in order to mitigate the volume expansion and improve electronic conductivity. At the same time, a-NbS4/20%VGCF is in situ coated with a Li7P3S11 solid electrolyte layer to achieve an intimate interfacial contact. The obtained a-NbS4/20%VGCF@15%Li7P3S11 nanocomposite exhibits a remarkable electronic conductivity (1.0 × 10-1 S cm-1) and ionic conductivity (5.5 × 10-4 S cm-1), which are improved by five and two orders of magnitude compared to those of NbS4, respectively. The Li/Li6PS5Cl/a-NbS4/20%VGCF@15%Li7P3S11 battery exhibits a high initial discharge capacity of 1043.25 mA h g-1 at 0.1 A g-1. Even at 0.5 A g-1, it could provide a reversible capacity of 403.2 mA h g-1 after 500 cycles. This work provides a promising cathode material for all-solid-state lithium batteries with improved ionic/electronic conductivity, high reversible capacity and superior cycling stability.

Inorganic Sodium Solid Electrolytes: Structure Design, Interface Engineering and Application.

All-solid-state sodium batteries (ASSSBs) are particularly attractive for large-scale energy storage and electric vehicles due to their exceptional safety, abundant resource availability, and cost-effectiveness. The growing demand for ASSSBs underscores the significance of sodium solid electrolytes; However, the existed challenges of sodium solid electrolytes hinder their practical application despite continuous research efforts. Herein, recent advancements and the challenges for sodium solid electrolytes from material to battery level are reviewed. The in-depth understanding of their fundamental properties, synthesis techniques, crystal structures and recent breakthroughs is presented. Moreover, critical challenges on inorganic sodium solid electrolytes are emphasized, including the imperative need to enhance ionic conductivity, fortifying interfacial compatibility with anode/cathode materials, and addressing dendrite formation issues. Finally, potential applications of these inorganic sodium solid electrolytes are explored in ASSSBs and emerging battery systems, offering insights into future research directions.

Tungsten and Boron Codoping toward High Ionic Conductivity and Stable Sodium Solid Electrolyte for All-Solid-State Sodium Batteries.

Sodium solid electrolytes with high ionic conductivity and good interfacial stability with sodium metal are crucial to realize high-performance all-solid-state sodium batteries. In this work, W and B-codoped Na3Sb1-xWxS4-xBx solid electrolytes are prepared by melt-quenching with further annealing. The synthesized Na3Sb0.95W0.05S3.95B0.05 solid electrolyte possesses a high ionic conductivity of 11.06 mS cm-1 under 25 °C and shows significantly improved interface compatibility with metal sodium. Specifically, Na/Na3Sb0.95W0.05S3.95B0.05/Na symmetric cell can stable cycle for 500 h under a current density of 0.05 mA cm-2. In addition, the resultant TiS2/Na3Sb0.95W0.05S3.95B0.05/Na battery exhibits an initial charge capacity of 164.1 mAh g-1 at 0.1 C with a capacity retention of 76.4% after 100 cycles. This work provides a new strategy to realize the high ionic conductivity of sodium solid electrolytes with improved interfacial stability with sodium anode.

Fluorinated Li10 GeP2 S12 Enables Stable All-Solid-State Lithium Batteries.

The instability of Li10 GeP2 S12 toward moisture and that toward lithium metal are two challenges for the application in all-solid-state lithium batteries. In this work, Li10 GeP2 S12 is fluorinated to form a LiF-coated core-shell solid electrolyte LiF@Li10 GeP2 S12 . Density-functional theory calculations confirm the hydrolysis mechanism of Li10 GeP2 S12 solid electrolyte, including H2 O adsorption on Li atoms of Li10 GeP2 S12 and the subsequent PS4 3- dissociation affected by hydrogen bond. The hydrophobic LiF shell can reduce the adsorption site, thus resulting in superior moisture stability when exposing in 30% relative humidity air. Moreover, with LiF shell, Li10 GeP2 S12 shows one order lower electronic conductivity, which can significantly suppress lithium dendrite growth and reduce the side reaction between Li10 GeP2 S12 and lithium, realizing three times higher critical current density to 3 mA cm-2 . The assembled LiNbO3 @LiCoO2 /LiF@Li10 GeP2 S12 /Li battery exhibits an initial discharge capacity of 101.0 mAh g-1 with a capacity retention of 94.8% after 1000 cycles at 1 C.

Toluene Tolerated Li9.88GeP1.96Sb0.04S11.88Cl0.12 Solid Electrolyte toward Ultrathin Membranes for All-Solid-State Lithium Batteries.

Sulfide solid electrolyte membranes employed in all-solid-state lithium batteries generally show high thickness and poor chemical stability, which limit the cell-level energy density and cycle life. In this work, Li9.88GeP1.96Sb0.04S11.88Cl0.12 solid electrolyte is synthesized with Sb, Cl partial substitution of P, S, possessing excellent toluene tolerance and stability to lithium. The formed SbS43- group in Li9.88GeP1.96Sb0.04S11.88Cl0.12 exhibits low adsorption energy and reactivity for toluene molecules, confirmed by first-principles density functional theory calculation. Using toluene as the solvent, ultrathin Li9.88GeP1.96Sb0.04S11.88Cl0.12 membranes with adjustable thicknesses can be well prepared by the wet coating method, and an 8 µm thick membrane exhibits an ionic conductivity of 1.9 mS cm-1 with ultrahigh ionic conductance of 1860 mS and ultralow areal resistance of 0.68 Ω cm-2 at 25 °C. The obtained LiCoO2|Li9.88GeP1.96Sb0.04S11.88Cl0.12 membrane|Li all-solid-state lithium battery shows an initial reversible capacity of 125.6 mAh g-1 with a capacity retention of 86.3% after 250 cycles at 0.1 C under 60 °C.

Circ_0083964 knockdown impedes rheumatoid arthritis progression via the miR-204-5p-dependent regulation of YY1.

BACKGROUND: Rheumatoid arthritis (RA) is a chronic inflammatory disease. Abnormal proliferation and inflammation of fibroblast-like synoviocytes (FLSs) are the main pathological features of the disease. Accumulating studies have identified that circular RNAs (circRNAs) were involved in the progression of RA. Our study was to assess the function and mechanism of circ_0083964 in RA. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were utilized to test the level of circ_0083964, miR-204-5p and YY1. Counting Kit-8 (CCK-8) assay, EdU assay, flow cytometry, transwell assay and wound-healing assay were utilized to test cell viability, proliferation, apoptosis, invasion and migration. Cell inflammation was estimated with enzyme-linked immunosorbent assay (ELISA) kits. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were employed to identify the target relationship between miR-204-5p and circ_0083964 or YY1. RESULTS: Circ_0083964 was highly expressed in RA synovial tissues and RA-FLSs. Circ_0083964 downregulation constrained proliferation, metastasis and inflammation and facilitated apoptosis in RA-FLSs. Furthermore, circ_0083964 served as a sponge of miR-204-5p, and rescue experiments proved that miR-204-5p deficiency overturned the suppressive impacts of circ_0083964 silencing on RA-FLSs progression. Additionally, we also verified that YY1 could be targeted by miR-204-5p, and its overexpression rescued the repressive impact of miR-204-5p introduction on RA-FLSs development. Besides that, we revealed that circ_0083964 mediated YY1 expression by regulating miR-204-5p. CONCLUSION: Circ_0083964 inhibition confined RA development by sponging miR-204-5p to hamper the YY1 level, which will provide a theoretical basis for the treatment of RA.

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 in rheumatoid arthritis: Longitudinal change after treatment and correlation with treatment efficacy of tumor necrosis factor inhibitors.

BACKGROUND: Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) correlates with treatment outcomes in inflammatory bowel disease and rheumatoid arthritis (RA). This study aimed to further evaluate the MALT1 longitudinal change and its relationship with tumor necrosis factor inhibitors (TNFi) response in RA patients. METHODS: Seventy-one RA patients receiving TNFi [etanercept (n = 42) or adalimumab (n = 29)] were enrolled. MALT1 was detected by RT-qPCR in peripheral blood samples of RA patients before treatment (W0), at week (W)4, W12, and W24 after treatment. RA patients were divided into response/non-response, remission/non-remission patients according to their treatment outcome at W24. Meanwhile, MALT1 was also detected by RT-qPCR in 30 osteoarthritis patients and 30 healthy controls (HCs). RESULTS: Mucosa-associated lymphoid tissue lymphoma translocation protein 1 was elevated in RA patients compared with HCs (Z=-6.392, p < 0.001) and osteoarthritis patients (Z = -5.020, p < 0.001). In RA patients, MALT1 was positively correlated with C-reactive protein (rs  = 0.347, p = 0.003), but not other clinical characteristics, treatment history, or current TNFi category. Meanwhile, MALT1 decreased from W0 to W12 in total RA patients (x2  = 86.455, p < 0.001), etanercept subgroup (x2  = 46.636, p < 0.001), and adalimumab subgroup (x2  = 41.291, p < 0.001). Moreover, MALT1 at W24 (p = 0.012) was decreased in response patients compared with non-response patients; MALT1 at W12 (p = 0.027) and W24 (p = 0.010) were reduced in remission patients than non-remission patients. In etanercept subgroup, MALT1 at W24 (p = 0.013) was decreased in response patients compared with non-response patients. In adalimumab subgroup, MALT1 at W24 (p = 0.015) was lower in remission patients than non-remission patients. CONCLUSION: Mucosa-associated lymphoid tissue lymphoma translocation protein 1 reduction after treatment is associated with response and remission to TNFi in RA patients.

MALT1 positively relates to Th17 cells, inflammation/activity degree, and its decrement along with treatment reflects TNF inhibitor response in ankylosing spondylitis patients.

BACKGROUND: Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) facilitates CD4+ T-cell differentiation, immune response, inflammation, and osteoclastogenesis. This study aimed to explore the relation between MALT1 and treatment efficacy to tumor necrosis factor inhibitor (TNFi) in ankylosing spondylitis (AS) patients. METHODS: This study recruited 73 AS patients underwent adalimumab treatment. Peripheral blood mononuclear cell (PBMC) was obtained at Week (W) 0, W4, W8, and W12 after treatment initiation; then, MALT1 was measured using RT-qPCR. Furthermore, PBMC and serum at W0 were proposed to flow cytometry and ELISA for Th1 cells, Th17 cells, IFN-γ, and IL-17A levels measurement. Besides, 20 osteoarthritis patients and 20 healthy controls (HCs) were enrolled to detect MALT1. RESULTS: Mucosa-associated lymphoid tissue lymphoma translocation protein 1 expression was higher in AS patients compared with HCs (p < 0.001) and osteoarthritis patients (p < 0.001). Besides, MALT1 expression was positively linked with CRP (p = 0.002), BASDAI (p = 0.026), PGADA (p = 0.040), ASDASCRP (p = 0.028), Th17 cells (p = 0.020), and IL-17A (p = 0.017) in AS patients, but did not relate to other clinical features, Th1 cells or IFN-γ (all p>0.050). MALT1 was decreased along with treatment only in AS patients with ASAS40 response (p < 0.001), but not in those without ASAS40 response (p = 0.064). Notably, MALT1 expression was of no difference at W0 (p = 0.328), W4 (p = 0.280), and W8 (p = 0.080), but lower at W12 (p = 0.028) in AS patients with ASAS40 response compared with those without ASAS40 response. CONCLUSION: Mucosa-associated lymphoid tissue lymphoma translocation protein 1 positively correlates with Th17 cells, inflammatory, and activity degree; meanwhile, its decrement along with treatment reflects the response to TNF inhibitor in AS patients.

Amorphous Titanium Polysulfide Composites with Electronic/Ionic Conduction Networks for All-Solid-State Lithium Batteries.

All-solid-state lithium/sulfide batteries are considered as next-generation high-energy-density batteries with unrivaled safety. However, sulfide cathodes generally suffer from insulating properties and huge volume expansion in all-solid-state lithium batteries. Based on amorphous TiS4 (a-TiS4), a certain proportion of Super P is introduced to suppress the volume expansion and increase the electronic conductivity. Meanwhile, a Li7P3S11 solid electrolyte is in situ coated on the surface of 20% Super P/a-TiS4, and the close interfacial contact between the active material and the solid electrolyte constructs a favorable ionic conduction path. As a result, a Li/75% Li2S-24% P2S5-1% P2O5/Li10GeP2S12/20% Super P/a-TiS4@Li7P3S11 battery shows a high reversible capacity of 507.4 mAh g-1 after 100 cycles at 0.1 A g-1. Even the current density increases to 1.0 A g-1, and it can also provide a reversible capacity of 349.8 mAh g-1 after 200 cycles. These results demonstrate a promising 20% Super P/a-TiS4@Li7P3S11 cathode material with electronic/ionic conduction networks for all-solid-state lithium batteries.

In Situ Formed Li-Ag Alloy Interface Enables Li10GeP2S12-Based All-Solid-State Lithium Batteries.

All-solid-state lithium-metal batteries (ASSLMBs) have received great interest due to their high potential to display both high energy density and safety performance. However, the poor compatibility at the Li/solid electrolyte (SE) interface and penetration of lithium dendrites during cycling strongly impede their successful commercialization. Herein, a thin Ag layer was introduced between Li and Li10GeP2S12 for the in situ formation of a Li-Ag alloy interface, thus tuning the interfacial chemistry and lithium deposition/dissolution behavior. Superior electrochemical properties and improved interfacial stability were achieved by optimizing the Ag thicknesses. The assembled symmetric cell with Li@Ag 1 µm showed a steady voltage evolution up to 1000 h with an areal capacity of 1 mAh cm-2. Moreover, a high reversible capacity of 106.5 mAh g-1 was achieved in an all-solid-state cell after 100 cycles, demonstrating the validity of the Ag layer. This work highlights the importance of the Li/SE interface re-engineering and provides a new strategy for improving the cycle life of ASSLMBs.

Wet-Milling Synthesis of Superionic Lithium Argyrodite Electrolytes with Different Concentrations of Lithium Vacancy.

The ionic conductivities of argyrodite electrolytes are significantly affected by the concentrations of lithium vacancy. Herein, a facile and rapid synthesis route is proposed to systematically investigate Li6-xPS5-xCl1+x (0 ≤ x ≤ 0.8) with different lithium vacancies by adjusting ratios of S/Cl. The highest ionic conductivity of the wet-milling synthesized Li5.4PS4.4Cl1.6 is 6.18 mS cm-1, which is attributed to higher lithium vacancy concentration and lower electrostatic interaction for ion migration. The Li/Li5.4PS4.4Cl1.6/Li symmetric cell cycles stably for 2000 h at 0.1 mA cm-2, showing excellent dendrite suppression capability. Moreover, the initial discharge capacity of LiCoO2/Li5.4PS4.4Cl1.6/Li all-solid-state battery is 126.0 mAh g-1 at 0.1C and the capacity retention is 83% after 50 cycles. The wet-milling method provides the possibility for rapid exploration and preparation of other argyrodite electrolytes in the future.

Ultrasmall Li2S-Carbon Nanotube Nanocomposites for High-Rate All-Solid-State Lithium-Sulfur Batteries.

Due to the intrinsic poor ionic/electronic conductivities of Li2S, it is a great challenge to realize high-rate all-solid-state lithium-sulfur batteries (ASSLSBs) with long cyclic performance. Herein, ultrasmall Li2S (∼15 nm) is evenly deposited on a carbon nanotube (CNT) via a facile liquid-phase method to address these issues. The unique structure of the Li2S deposited on a CNT composite cathode can improve ionic/electronic conductivities of Li2S effectively and relieve the generated internal stress/strain during cycling. Specifically, the resultant Li/75%Li2S-24%P2S5-1%P2O5/Li10GeP2S12/Li2S-53%CNT ASSLSBs show a reversible capacity of 651.4 mAh g-1 under 1.0C at 60 °C after 300 cycles and even at a much higher cathode load of 5.08 mg cm-2, a high discharge capacity of 556 mAh g-1 can still be obtained under 0.1C after 20 cycles. The outstanding electrochemical performances are also attributed to the high diffusion coefficient of Li2S-53%CNT, which is 39 times that of pristine Li2S. This work presents an efficient procedure to design cathode materials with high ionic/electronic conductivities and paves the way for the successful commercialization of high-rate ASSLSBs.

Densified Li6PS5Cl Nanorods with High Ionic Conductivity and Improved Critical Current Density for All-Solid-State Lithium Batteries.

Solid electrolytes are receiving great interest owing to their good mechanical properties and high lithium-ion transference number, which could potentially suppress lithium dendrites. However, lithium dendrites can still penetrate solid electrolytes even at low current densities. In this work, a flat-surface Li6PS5Cl nanorod pellet with high density is achieved, which exhibits an ionic conductivity as high as 6.11 mS cm-1 at 25 °C. The flat surface of the pellet is beneficial for the homogeneous lithium deposition, and the dense pellet microstructure can suppress the growth of lithium dendrites along the grain boundaries, leading to a significantly improved critical current density of 1.05 mA cm-2 at 25 °C. The resultant dense Li6PS5Cl pellet is further employed in a LiCoO2/Li6PS5Cl/Li all-solid-state lithium battery, showing an initial discharge capacity of 115.3 mAh g-1 at 1C (0.35 mA cm-2, 25 °C) with a capacity retention of 80.3% after 100 cycles.

Self-Formed Electronic/Ionic Conductive Fe3 S4  @ S @ 0.9Na3 SbS4 ⋠0.1NaI Composite for High-Performance Room-Temperature All-Solid-State Sodium-Sulfur Battery.

Fe3 S4  @ S @ 0.9Na3 SbS4 ⋅0.1NaI composite cathode is prepared through one-step wet-mechanochemical milling procedure. During milling process, ionic conduction pathway is self-formed in the composite due to the formation of 0.9Na3 SbS4 ⋅0.1NaI electrolyte without further annealing treatment. Meanwhile, the introduction of Fe3 S4 can increase the electronic conductivity of the composite cathode by one order of magnitude and nearly double enhance the ionic conductivities. Besides, the aggregation of sulfur is effectively suppressed in the obtained Fe3 S4  @ S @ 0.9Na3 SbS4 ⋅0.1NaI composite, which will enhance the contact between sulfur and 0.9Na3 SbS4 ⋅0.1NaI electrolyte, leading to a decreased interfacial resistance and improving the electrochemical kinetics of sulfur. Therefore, the resultant all-solid-state sodium-sulfur battery employing Fe3 S4  @ S @ 0.9Na3 SbS4 ⋅0.1NaI composite cathode shows discharge capacity of 808.7 mAh g-1 based on Fe3 S4 @S and a normalized discharge capacity of 1040.5 mAh g-1 for element S at 100 mA g-1 for 30 cycles at room temperature. Moreover, the battery also exhibits excellent cycling stability with a reversible capacity of 410 mAh g-1 at 500 mA g-1 for 50 cycles, and superior rate capability with capacities of 952.4, 796.7, 513.7, and 445.6 mAh g-1 at 50, 100, 200, and 500 mA g-1 , respectively. This facile strategy for sulfur-based composite cathode is attractive for achieving room-temperature sodium-sulfur batteries with superior electrochemical performance.

Passivation of the Cathode-Electrolyte Interface for 5 V-Class All-Solid-State Batteries.

An all-solid-state battery is a potentially superior alternative to a state-of-the-art lithium-ion battery owing to its merits in abuse tolerance, packaging, energy density, and operable temperature ranges. In this work, a 5 V-class spinel LiNi0.5Mn1.5O4 (LNMO) cathode is targeted to combine with a high-ionic-conductivity Li6PS5Cl (LPSCl) solid electrolyte for developing high-performance all-solid-state batteries. Aiming to passivate and stabilize the LNMO-LPSCl interface and suppress the unfavorable side reactions such as the continuous chemical/electrochemical decomposition of the solid electrolyte, oxide materials including LiNbO3, Li3PO4, and Li4Ti5O12 are rationally applied to decorate the surface of pristine LNMO particles with various amounts through a wet-chemistry approach. Electrochemical characterization demonstrates that the composite cathode consisting of 8 wt % LiNbO3-coated LNMO and LPSCl in a weight ratio of 70:30 delivers the best electrochemical performance with an initial discharge capacity of 115 mA h g-1 and a reversible discharge capacity of 80 mA h g-1 at the 20th cycle, suggesting that interfacial passivation is an effective strategy to ensure the operation of 5 V-class all-solid-state batteries.

Selenium-Infused Ordered Mesoporous Carbon for Room-Temperature All-Solid-State Lithium-Selenium Batteries with Ultrastable Cyclability.

Selenium with a similar reaction mechanism with sulfur and a much higher electronic conductivity is considered to be a promising cathode for all-solid-state rechargeable batteries. Herein, selenium-infused ordered mesoporous carbon composites (Se/CMK-3) are successfully prepared by a melt-diffusion method from a ball-milled mixture of Se and CMK-3 (Se-CMK-3). Furthermore, their electrochemical performances are evaluated in all-solid-state lithium-selenium batteries at room temperature. Typically, Li/75%Li2S-24%P2S5-1%P2O5/Li10GeP2S12/Se/CMK-3 all-solid-state lithium-selenium batteries exhibit high reversible capacity of 488.7 mAh g-1 at 0.05 C after 100 cycles. Even being cycled at 0.5C, it still maintains a discharge capacity of 268.7 mAh g-1 after 200 cycles. The excellent electrochemical performances could be attributed to the enhanced electronic/ionic conductivities and structural integrity with the addition of the CMK-3 matrix.

Co3S4@Li7P3S11 Hexagonal Platelets as Cathodes with Superior Interfacial Contact for All-Solid-State Lithium Batteries.

Poor solid-solid contact between an electrode and solid electrolyte is a great challenge for all-solid-state lithium batteries (ASSLBs) which results in limited ion transport and eventually leads to rapid capacity fading. Two-dimensional (2D) materials have incomparable advantage in the construction of the desired interface because of their flat surface and large specific surface area. In order to realize intimate interfacial contact and superior ion transport, monodisperse 2D Co3S4 hexagonal platelets as cathodes for all ASSLBs are synthesized through a series of topological reactions followed with in situ coating of tiny Li7P3S11 using a liquid-phase method. The unique 2D hexagonal platelets are favorable for in situ solid electrolyte coating. Moreover, the well-designed interfacial structure can make the electrode materials contact with solid electrolytes more closely, contributing to a remarkable improvement on electrochemical performance. ASSLBs employing the Co3S4@Li7P3S11 composite platelets as a cathode deliver a large reversible capacity of 685.9 mA h g-1 at 0.5 A g-1 for 50 cycles. Even at a high current density of 1 A g-1, the Co3S4@Li7P3S11 composite cathode still exhibits a high capacity of 457.3 mA h g-1 after 100 cycles. This work provides a simple strategy to design the composite electrode with intimate contact and superior ion transport via morphology controlling.

Transitional Metal Catalytic Pyrite Cathode Enables Ultrastable Four-Electron-Based All-Solid-State Lithium Batteries.

All-solid-state batteries can enable reversible four lithium ion storage for pyrite (FeS2) at a cutoff voltage of 1.0-3.0 V. However, strain/stress concentration generating electrode pulverization and sluggish electrochemical reaction of lithium sulfide and sulfur will affect the long cycling stability of the battery. Through experiments and density functional theory (DFT) calculations, it is proved that nanostructure engineering and electronic conduction improvement with introduction of catalytic cobalt can effectively improve the electrochemical activity of FeS2. The optimized loose structured Co0.1Fe0.9S2 based all-solid-state lithium batteries show reversible capacities of 860.5, 797.7, 685.8, and 561.8 mAh g-1 after five cycles at 100, 200, 500, and 1000 mA g-1, respectively, and a stable capacity of 543.5 mAh g-1 can be maintained after cycling at a current density of 500 mA g-1 for 100 cycles. Ex situ TEM and Raman results reveal that, after the first cycle, the reversible reaction 2Li2S + Fe ↔ FeSy + (2 - y)S + 4Li+ + 4e- proceeds from the following cycles onward, while nanocrystalline mackinawite FeS, Fe(III)-containing mackinawite FeS, and Fe3S4 are generated after the first discharge-charge process. This work provides a facile method for improving the electrochemical performance for multi-electron reaction mechanism based all-solid-state lithium batteries.