Towards All-Solid-State Polymer Batteries: Going Beyond PEO with Hybrid Concepts

To go beyond polyethylene oxide in lithium metal batteries, a hybrid polymer/oligomer cell design is presented, where an ester oligomer provides high ionic conductivity of 0.2 mS cm⁻¹ at 40 °C within thicker composite cathodes with active mass loadings of up to 11 mg cm⁻² (LiNbO₃-coated) LiNi_0.6Mn_0.2Co_0.2 (NMC622), while a 30 µm thin scaffold-supported polymer electrolyte affords mechanical stability. Corresponding discharge capacities of the hybrid cells exceed 170 mAh g⁻¹ (11 mg cm⁻²) or 160 mAh g⁻¹ (6 mg cm⁻²) at rates of either 0.1 or 0.25 C. Multilayer pouch cells are projected to enable energy densities of 235 Wh L⁻¹ (6 mg cm⁻²) and even up to 356 Wh L⁻¹ (11 mg cm⁻²), clearly superior to other reported polymer-based cell designs. Polyester electrolytes are environmentally benign and safer compared to common liquid electrolytes, while the straightforward synthesis and affordability of precursors render hybrid polyester electrolytes suitable candidates for future application in solid-state lithium metal batteries.     

Solvent-Free Electrolyte for High-Temperature Rechargeable Lithium Metal Batteries

The formation of lithiophobic inorganic solid electrolyte interphase (SEI) on Li anode and cathode electrolyte interphase (CEI) on the cathode is beneficial for high-voltage Li metal batteries. However, in most liquid electrolytes, the decomposition of organic solvents inevitably forms organic components in the SEI and CEI. In addition, organic solvents often pose substantial safety risks due to their high volatility and flammability. Herein, an organic-solvent-free eutectic electrolyte based on low-melting alkali perfluorinated-sulfonimide salts is reported. The exclusive anion reduction on Li anode surface results in an inorganic, LiF-rich SEI with high capability to suppress Li dendrite, as evidenced by the high Li plating/stripping CE of 99.4% at 0.5  mA cm⁻² and 1.0 mAh cm⁻², and 200-cycle lifespan of full LiNi_0.8Co_0.15Al_0.05O₂ (2.0 mAh cm⁻²) || Li (20 µm) cells at 80 °C. The proposed eutectic electrolyte is promising for ultrasafe and high-energy Li metal batteries.     

Hollow Molybdate Microspheres as Catalytic Hosts for Enhancing the Electrochemical Performance of Sulfur Cathode under High Sulfur Loading and Lean Electrolyte

Lithium–sulfur battery possesses a high energy density; however, its application is severely blocked by several bottlenecks, including the serious shuttling behavior and sluggish redox kinetics of sulfur cathode, especially under the condition of high sulfur loading and lean electrolyte. Herein, hollow molybdate (CoMoO₄, NiMoO₄, and MnMoO₄) microspheres are introduced as catalytic hosts to address these issues. The molybdates present a high intrinsic electrocatalytic activity for the conversion of soluble lithium polysulfides, and the unique hollow spherical structure could provide abundant sites and spatial confinement for electrocatalysis and inhibiting shuttling, respectively. Meanwhile, it is demonstrated that the unique adsorption of molybdates toward polysulfides exhibits a “volcano-type” feature with the catalytic performance following the Sabatier principle. The NiMoO₄ hollow microspheres with moderate adsorption show the highest electrocatalytic activity, which is favorable for enhancing the electrochemical performance of sulfur cathode. Especially, the S/NiMoO₄ composite could achieve a high areal capacity of 7.41 mAh cm⁻² (906.2 mAh g⁻¹) under high sulfur loading (8.18 mg cm⁻²) and low electrolyte/sulfur ratio (E/S, 4 µL mg⁻¹). This work offers a new perspective on searching accurate rules for selecting and designing effective host materials in the lithium–sulfur battery.     

Rational Design of Sulfonamide-Based Additive Enables Stable Solid Electrolyte Interphase for Reversible Zn Metal Anode

The solid electrolyte interphase (SEI)-forming additives strategy is of great significance for improving the cycle stability of zinc (Zn) anodes. Although various additives have been reported, the relationship between their molecular structures and SEI chemistries is poorly understood. Herein, a molecular design principle for sulfonamide-containing additives that endow Zn anodes with a robust SEI layer is proposed. The incorporation of the benzene ring and amino group (−NH₂) leads to high adsorption energy, low lowest unoccupied molecular orbital lowest unoccupied molecular orbital (LUMO), and a small highest occupied molecular orbital-LUMO (HOMO-LUMO) gap, facilitating the reduction process of sulfanilamide (SA) additives. Coupled with SA/ZnSO₄ electrolytes, Zn|Zn symmetric cells deliver an ultralong cycle life of 4800 h (200 days) at 2 mA cm⁻² and 2 mAh cm⁻². Additionally, a high cumulative plated capacity (CPC) of 6000 mAh cm⁻² and 2700 mAh cm⁻² is also achieved at a capacity per cycle of 10 mAh cm⁻² and 30 mAh cm⁻², respectively. More importantly, the versatility of SA additives is also demonstrated in Zn-V₂O₅, Zn-I₂, and Zn-MnO₂ full cells at a low N/P ratio (the theoretical capacity ratio between the negative and positive electrode) of 5.3, 8.3, and 4.5, respectively. This molecular structure strategy provides a promising path to develop effective SEI-forming additives.     

High-Performance Garnet-Type Solid-State Lithium Metal Batteries Enabled by Scalable Elastic and Li+-Conducting Interlayer

Promoting the interfacial Li⁺ transport and suppressing detrimental lithium dendrites are the main challenges for developing practical solid-state lithium metal batteries. In this respect, interface rationalizing to synergize the enhancement of ion transport and suppression of lithium dendrites is of paramount significance. Herein, a novel strategy is demonstrated to address those issues by a designed multifunctional composite interlayer. The photocrosslinkable polymer is introduced in a scalable elastic skeleton, which promotes the migration and diffusion of Li⁺. Moreover, adding perfluoropolyether in the interlayer benefits to regulating the formation of LiF-rich interface, sufficiently suppress the growth of lithium dendrites. Benefitting from the elasticity, high Li⁺ conductivity and the lithium dendrites suppression capability, the interlayer can significantly improve the interfacial performance of the solid electrolyte/lithium interface, thus leading to the greatly enhanced electrochemical performance of solid-state lithium metal batteries. A high critical current density of 3.6 mA cm⁻² and a long cycling life at 1.0 mA cm⁻² for >400 h are achieved for the symmetric cells. Besides, when used in a pouch-type full cell coupled with LiNi_0.6Co_0.2Mn_0.2O₂ cathode, a high charged capacity of 3.25 mAh cm⁻² can be maintained through 20 cycles, demonstrating its great potentials for practical application.     

Expediting Stepwise Sulfur Conversion via Spontaneous Built-In Electric Field and Binary Sulfiphilic Effect of Conductive NbB2-MXene Heterostructure in Lithium–Sulfur Batteries

Fabricating metal boride heterostructures and deciphering their interface interaction mechanism on accelerating polysulfide conversion at atomic levels are meaningful yet challenging in lithium–sulfur batteries (LSBs). Herein, novel highly-conductive and binary sulfiphilic NbB₂-MXene heterostructures are elaborately designed with spontaneous built-in electric field (BIEF) via a simple one-step borothermal reduction strategy. Experimental and theoretical results reveal that Nb and B atoms can chemically bond with polysulfides, thereby enriching chemical anchor and catalytic active sites. Meanwhile, the spontaneous BIEF induces interfacial charge redistribution to make more electrons transferred to surface NbB₂ sites, thereby weakening its strong adsorption property yet accelerating polysulfide transfer and electron diffusion on hetero-interface, so providing moderate polysulfide adsorb-ability yet decreasing sulfur-species conversion energy barriers, further boosting the intrinsically catalytic activity of NbB₂-MXene for accelerated bidirectional sulfur conversion. Thus, S/NbB₂-MXene cathode presents high initial capacity of 1310.1 mAh g⁻¹ at 0.1 C, stable long-term lifespan with 500 cycles (0.076% capacity decay per cycle) at 1 C, and large areal capacity of 6.5 mAh cm⁻² (sulfur loading: 7.0 mg cm⁻² in lean electrolyte of 5 µL mg_s⁻¹) at 0.1 C. This work clearly unveils the mechanism of interfacial BIEF and binary sulfiphilic effect on accelerating stepwise sulfur conversion at atomic levels.     

Inorganic Filler Enhanced Formation of Stable Inorganic-Rich Solid Electrolyte Interphase for High Performance Lithium Metal Batteries

Lithium metal (LM) is a promising anode material for next generation lithium ion based electrochemical energy storage devices. Critical issues of unstable solid electrolyte interphases (SEIs) and dendrite growth however still impede its practical applications. Herein, a composite gel polymer electrolyte (GPE), formed through in situ polymerization of pentaerythritol tetraacrylate with fumed silica fillers, is developed to achieve high performance lithium metal batteries (LMBs). As evidenced theoretically and experimentally, the presence of SiO₂ not only accelerates Li⁺ transport but also regulates Li⁺ solvation sheath structures, thus facilitating fast kinetics and formation of stable LiF-rich interphase and achieving uniform Li depositions to suppress Li dendrite growth. The composite GPE-based Li||Cu half-cells and Li||Li symmetrical cells display high Coulombic efficiency (CE) of 90.3% after 450 cycles and maintain stability over 960 h at 3 mA cm⁻² and 3 mAh cm⁻², respectively. In addition, Li||LiFePO₄ full-cells with a LM anode of limited Li supply of 4 mAh cm⁻² achieve capacity retention of 68.5% after 700 cycles at 0.5 C (1 C = 170 mA g⁻¹). Especially, when further applied in anode-free LMBs, the carbon cloth||LiFePO₄ full-cell exhibits excellent cycling stability with an average CE of 99.94% and capacity retention of 90.3% at the 160th cycle at 0.5 C.     

Rational Electronic and Structural Designs Advance BiCuSeO Thermoelectrics

In this work, a record high thermoelectric figure-of-merit ZT of 1.6 ± 0.2 at 873 K in p-type polycrystalline Bi_0.94Pb_0.06CuSe_1.01O_0.99 by a synergy of rational band manipulation and novel nanostructural design is reported. First-principles density functional theory calculation results indicate that the density of state at the Fermi level that crosses the valence band can be significantly reduced and the measured optical bandgap can be enlarged from 0.70 to 0.74 eV by simply replacing 1% O with 1% Se, both indicating a potentially reduced carrier concentration and in turn, an improved carrier mobility and a boosted power factor up to 9.0 µW cm⁻¹ K⁻². Meanwhile, comprehensive characterizations reveal that under Se-rich condition, Cu₂Se secondary microphases and significant lattice distortions triggered by Pb-doping and Se-substitution can be simultaneously achieved, contributing to a reduced lattice thermal conductivity of 0.4 W m⁻¹ K⁻¹. Furthermore, a unique shear exfoliation technique enables an effective grain refinement with higher anisotropy of the polycrystalline pellet, leading to a further improved power factor up to 10.9 µW cm⁻¹ K⁻² and a further reduced lattice thermal conductivity of 0.30 W m⁻¹ K⁻¹, which gives rise to record high ZT.     

Tandem Carbon Hollow Spheres with Tailored Inner Structure as Sulfur Immobilization for Superior Lithium–Sulfur Batteries

The construction of lithium–sulfur battery cathode materials while simultaneously achieving high areal sulfur-loading, adequate sulfur utilization, efficient polysulfides inhibition, rapid ion diffusion, etc. remains a major challenge. Herein, an internal regulatory strategy to fabricate the unique walnut-like yolk–shell carbon flower@carbon nanospheres is presented (WSYCS) as sulfur hosts. The internal carbon flower, suitable cavity, and external carbon layer effectively disperse the insulate sulfur, accommodate volumetric expansion, and confine polysulfides, thus improving the performance of lithium–sulfur batteries. The finite element simulation method also deduces the enhanced Li⁺ diffusion and lithium–sulfur reaction kinetics. More importantly, WSYCS2 is grafted onto carbon fiber (CF) by electro-spinning method to form a tandem WSYCS2@CF 3D film as a sulfur host for the free-standing electrode. The corresponding battery exhibits an extremely high areal capacity of 15.5 mAh cm⁻² with a sulfur loading of 13.4 mg cm⁻². Particularly, the flexible lithium–sulfur pouch cell delivers a high capacity of 8.1 mAh cm⁻² and excellent capacity retention of 65% over 800 cycles at a relatively high rate of 1C, corresponding to a calculated energy density of 539 Wh kg⁻¹ and 591 Wh L⁻¹. This work not only provides guidance for tailoring thick carbon/sulfur electrodes but also boosts the development of practical lithium–sulfur batteries.     

Advanced Zinc–Iodine Batteries with Ultrahigh Capacity and Superior Rate Performance Based on Reduced Graphene Oxide and Water-in-Salt Electrolyte

Aqueous rechargeable zinc–iodine batteries have received increasing attention in the field of portable electronics due to their high safety, low-cost, and great electrochemical performance. However, the insulated nature of iodine and the unrestricted shuttle effect of soluble triiodide seriously limit the lifespan and Coulombic efficiency (CE) of the batteries. Herein, a high-performance zinc–iodine energy storage system based on the hydrothermal reduced graphene oxide (rGO) and a high concentration zinc chloride water-in-salt electrolyte are promoted. The 3D microporous structures and outstanding electrical conductivity of rGO make it an excellent host for iodine, while the water-in-salt electrolyte effectively suppresses the shuttle effect of triiodide and improves the CE of the system. As a result, an ultra-high I₂ mass loading of 25.33 mg cm⁻² (loading ratio of 71.69 wt.%) is realized during the continuous charging/discharging process. The batteries deliver a high capacity of 6.5 mAh cm⁻² at 2 mA cm⁻² with a much-improved CE of 95% and a prominent rate performance with capacity of 1 mAh cm⁻² at 80 mA cm⁻². A stable long-term cycling performance is also achieved with capacity retention of 2 mAh cm⁻² after 2000 cycles at 50 mA cm⁻².     

The Restrained Li/Gel Polymer Electrolyte Interface Deterioration Enabled by the Synergetic Effect of Ultra-Lithiophilic Interphase and Interfacial Coupling Skeleton

Quasi-solid-state lithium metal batteries are deemed as one of the most promising next-generation energy storage devices due to their enhanced safety and high energy density. However, the Li/Gel polymer Electrolyte (GPE) interface deterioration induced by the side reactions, dendrite growth during Li plating, and contact loss during Li stripping will inevitably lead to the failure of the battery. Herein, a Li/Li₂₃Sr₆–Li₃N/Sr₂N anode structure (LSN) prepared by hot-rolling process is designed, where Sr₂N serves as an inert skeleton to retain the interfacial coupling and to avoid contact loss. At the same time, the Li₃N–Li₂₃Sr₆ interphase with high Li adsorption energy and fast Li⁺ transfer kinetics regulate the Li plating behavior. Benefitting from the design, when coupled with the carbonate-based GPE, the lifespan of the symmetric battery with the LSN is extended to 1300 h at 0.2 mA cm⁻²/0.2 mAh cm⁻². Furthermore, the LSN||LiFePO₄ (LFP) full cell exhibits a steady cycle with extremely low voltage polarization at 0.5 C after 200 cycles. This study provides a practical strategy to stabilize the Li/GPE interface and deepens the understanding of Li⁺ plating/stripping behaviors through the interphase.     

A Flexible and Safe Planar Zinc-Ion Micro-Battery with Ultrahigh Energy Density Enabled by Interfacial Engineering for Wearable Sensing Systems

Aqueous zinc-ion micro-batteries (ZIMBs) have attracted considerable attention owing to their reliable safety, low cost, and great potential for wearable devices. However, current ZIMBs still suffer from various critical issues, including short cycle life, poor mechanical stability, and inadequate energy density. Herein, the fabrication of flexible planar ZIMBs with ultrahigh energy density by interfacial engineering in the screen-printing process based on high-performance MnO₂-based cathode materials is reported. The Ce-doped MnO₂ (Ce-MnO₂) exhibits significantly enhanced capacity (389.3 mAh g⁻¹), considerable rate capability and admirable cycling stability than that of the pure MnO₂. Importantly, the fabrication of micro-electrodes with ultrahigh mass loading of Ce-MnO₂ (24.12 mg cm⁻²) and good mechanical stability is achieved through optimizing the interfacial bonding between different printed layers. The fabricated planar ZIMBs achieve a record high capacity (7.21 mAh cm⁻² or 497.31 mAh cm⁻³) and energy density (8.43 mWh cm⁻² or 573.45 mWh cm⁻³), as well as excellent flexibility. Besides, a wearable self-powered sensing system for environmental monitoring is further demonstrated by integrating the planar ZIMBs with flexible solar cells and a multifunctional sensor array. This work sheds light on the development of high-performance planar ZIMBs for future self-powered and eco-friendly smart wearable electronics.     

A Semi-Liquid Electrode toward Stable Zn Powder Anode

Zn powder anode possesses great versatility compared to the Zn foil counterpart, but the rough surface with a high surface area aggravates the corrosion and dendrite growth. Herein, a dendrite-free and anti-corrosive semi-liquid Zn anode (SLA) is successfully fabricated based on Zn powder and a thickening agent. Benefiting from the rheological property, the unique anode effectively releases the stress induced by Zn plating, especially under high-current densities. Meanwhile, the dual-conductive medium, i.e., ionic and electronic, homogenizes the ion flux and allows the stripping/plating to occur within the entire anode. In a symmetric cell, the SLA anode exhibits stable electrochemical behavior with a prolonged lifespan at the current density of 5 mA cm⁻²/10 mA cm⁻² under the capacity of 5 mAh cm⁻²/10 mAh cm⁻². Improved durability of more than 5000 cycles is endowed when assembling an SLA anode with a vanadium-based cathode. This study provides an electrode rheology-based approach to overcome the stability challenge of powder anode for scale-up manufacturing.     

Si/SiO2@Graphene Superstructures for High-Performance Lithium-Ion Batteries

The superstructure composed of various functional building units is promising nanostructure for lithium-ion batteries (LIBs) anodes with extreme volume change and structure instability, such as silicon-based materials. Here, a top-down route to fabricate Si/SiO₂@graphene superstructure is demonstrated through reducing silicalite-1 with magnesium reduction and depositing carbon layers. The successful formation of superstructure lies on the strong 3D network formed by the bridged-SiO₂ matrix coated around silicon nanoparticles. Furthermore, the mesoporous Si/SiO₂ with amorphous bridged SiO₂ facilitates the deposition of graphene layers, resulting in excellent structural stability and high ion/electron transport rate. The optimized Si/SiO₂@graphene superstructure anode delivers an outstanding cycling life for ≈1180 mAh g⁻¹ at 2 A g⁻¹ over 500 cycles, excellent rate capability for ≈908 mAh g⁻¹ at 12 A g⁻¹, great areal capacity for ≈7 mAh cm⁻² at 0.5 mA cm⁻², and extraordinary mechanical stability. A full cell test using LiFePO₄ as the cathode manifests a high capacity of 134 mAh g⁻¹ after 290 loops. More notably, a series of technologies disclose that the Si/SiO₂@graphene superstructure electrode can effectively maintain the film between electrode and electrolyte in LIBs. This design of Si/SiO₂@graphene superstructure elucidates a promising potential for commercial application in high-performance LIBs.     

Rational Design of Multifunctional Integrated Host Configuration with Lithiophilicity-Sulfiphilicity toward High-Performance Li–S Full Batteries

High-energy-density Li–S batteries are considered one of the next-generation energy storage systems, but the uncontrolled Li-dendrite growth in Li metal anodes and the shuttling of polysulfides in S cathode severely impede the commercial development of Li–S batteries. Herein, a conductive composite architecture that is made up of bio-derived N-doped porous carbon fiber bundles (N-PCFs) with co-imbedded cobalt and niobium carbide nanoparticles is employed as a multifunctional integrated host for simultaneously addressing the challenges in both Li anodes and S cathodes. The implantation of Co and NbC nanoparticles bestows the N-PCFs matrix with synergistically enhanced degree of graphitization, electrical conductivity, hierarchical porosity, and surface polarization. Theoretical calculations and experimental results show that NbC with specific lithiophilic and sulfiphilic features can synchronously regulate the Li and S electrochemistry by realizing homogeneous lithium deposition with suppressed Li-dendrite growth and exerting catalytic effects for promoting the polysulfide conversion together with fast Li₂S nucleation. Hence, the assembled Li–S full batteries exhibit a superb rate capability (704 mAh g⁻¹ at 5 C) and cycling life (≈82.3% capacity retention after 500 cycles) at a sulfur loading over 3.0 mg cm⁻², as well as high reversible areal capacity (>6.0 mAh cm⁻²) even at a higher sulfur loading of 6.7 mg cm⁻².     

Achieving Superior Thermoelectric Performance in Ge4Se3Te via Symmetry Manipulation with I–V–VI2 Alloying

Although orthorhombic GeSe is predicted to have an ultrahigh figure of merit, ZT ≈ 2.5, up to now, the highest experimental value is ≈0.2 due to the low carrier concentration (n_H ≈ 10¹⁸ cm⁻³). Improving symmetry is an effective approach for enhancing the ZT of GeSe-based materials. With Te-alloying, Ge₄Se₃Te displays the two-dimensional hexagonal structure and high n_H ≈ 1.23 × 10²¹ cm⁻³. Interestingly, Ge₄Se₃Te transformed from the hexagonal into the rhombohedral phase with only ≈2% I–V–VI₂-alloying (I = Li, Na, K, Cu, Ag; V = Sb, Bi; VI = Se, Te). According to the calculated results of Ge_0.82Ag_0.09Bi_0.09Se_0.614Te_0.386 single-crystal grown via AgBiTe₂-alloying, it exhibits a higher valley degeneracy than the hexagonal Ge₄Se₃Te. For instance, AgBiTe₂-alloying induces a strong band convergence and band inversion effect, resulting in a significantly enhanced Seebeck coefficient and power factor with a similar n_H from 17 µV K⁻¹ and 0.63 µW cm⁻¹ K⁻² for pristine Ge₄Se₃Te to 124 µV K⁻¹ and 5.97 µW cm⁻¹ K⁻² for 12%AgBiTe₂-alloyed sample, respectively. Moreover, the sharply reduced phonon velocity, nano-domain wall structure, and strong anharmonicity lead to low lattice thermal conductivity. As a result, a record-high average ZT ≈0.95 over 323–773 K with an excellent ZT ≈ 1.30 is achieved at 723 K.     

Non-Flammable Electrolyte with Lithium Nitrate as the Only Lithium Salt for Boosting Ultra-Stable Cycling and Fire-Safety Lithium Metal Batteries

Lithium metal batteries (LMBs) attract considerable attention for their incomparable energy density. However, safety issues caused by uncontrollable lithium dendrites and highly flammable electrolyte limit large-scale LMBs applications. Herein, a low-cost, thermally stable, and low environmentally-sensitive lithium nitrate (LiNO₃) is proposed as the only lithium salt to incorporate with nonflammable triethyl phosphate and fluoroethylene carbonate (FEC) co-solvent as the electrolyte anticipated to enhance the performance of LMBs. Benefiting from the presence of NO₃⁻ and FEC with strong solvation effect and easily reduced ability, a Li₃N–LiF-rich stable solid electrolyte interphase is constructed. Compared to commercial electrolytes, the proposed electrolyte has a high Coulombic efficiency of 98.31% in Li-Cu test at 1 mA cm⁻² of 1.0 mAh cm⁻² with dendrite-free morphology. Additionally, the electrolyte system shows high voltage stability and cathode electrolyte interphase film-forming properties with stable cycling performances, which exhibit outstanding capacity retention rates of 96.39% and 83.74% after 1000 cycles for LFP//Li and NCM811//Li, respectively. Importantly, the non-flammable electrolyte delays the onset of combustion in lithium metal soft pack batteries by 255 s and reduces the peak heat release by 21.02% under the continuous external high-temperature heating condition. The novel electrolyte can contribute immensely to developing high-electrochemical-performance and high-safety LMBs.     

Enabling High-Performance NASICON-Based Solid-State Lithium Metal Batteries Towards Practical Conditions

Solid-state lithium metal batteries (SSLMBs) are promising next-generation high-energy rechargeable batteries. However, the practical energy densities of the reported SSLMBs have been significantly overstated due to the use of thick solid-state electrolytes, thick lithium (Li) anodes, and thin cathodes. Here, a high-performance NASICON-based SSLMB using a thin (60 µm) Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP) electrolyte, ultrathin (36 µm) Li metal, and high-loading (8 mg cm⁻²) LiFePO₄ (LFP) cathode is reported. The thin and dense LAGP electrolyte prepared by hot-pressing exhibits a high Li ionic conductivity of 1 × 10⁻³ S cm⁻¹ at 80 °C. The assembled SSLMB can thus deliver an increased areal capacity of ≈1 mAh cm⁻² at C/5 with a high capacity retention of ≈96% after 50 cycles under 80 °C. Furthermore, it is revealed by synchrotron X-ray absorption spectroscopy and in situ high-energy X-ray diffraction that the side reactions between LAGP electrolyte and LFP cathode are significantly suppressed, while rational surface protection is required for Ni-rich layered cathodes. This study provides valuable insights and guidelines for the development of high-energy SSLMBs towards practical conditions.     

In-Built Quasi-Solid-State Poly-Ether Electrolytes Enabling Stable Cycling of High-Voltage and Wide-Temperature Li Metal Batteries

Developing solid-state electrolytes with good compatibility for high-voltage cathodes and reliable operation of batteries over a wide-temperature-range are two bottleneck requirements for practical applications of solid-state metal batteries (SSMBs). Here, an in situ quasi solid-state poly-ether electrolyte (SPEE) with a nano-hierarchical design is reported. A solid-eutectic electrolyte is employed on the cathode surface to achieve highly-stable performance in thermodynamic and electrochemical aspects. This performance is mainly due to an improved compatibility in the electrode/electrolyte interface by nano-hierarchical SPEE and a reinforced interface stability, resulting in superb-cyclic stability in Li || Li symmetric batteries ( > 4000 h at 1 mA cm⁻²/1 mAh cm⁻²; > 2000 h at 1 mA cm⁻²/4 mAh cm⁻²), which are the same for Na, K, and Zn batteries. The SPEE enables outstanding cycle-stability for wide-temperature operation (15–100 ° C) and 4 V-above batteries (Li || LiCoO₂ and Li || LiNi_0.8Co_0.1Mn_0.1O₂). The work paves the way for development of practical SSMBs that meet the demands for wide-temperature applicability, high-energy density, long lifespan, and mass production.     

Polyether-b-Amide Based Solid Electrolytes with Well-Adhered Interface and Fast Kinetics for Ultralow Temperature Solid-State Lithium Metal Batteries

Solid-state lithium metal batteries (SSLMBs) are highly desirable for energy storage because of the urgent need for higher energy density and safer batteries. However, it remains a critical challenge for stable cycling of SSLMBs at low temperature. Here, a highly viscoelastic polyether-b-amide (PEO-b-PA) based composite solid-state electrolyte is proposed through a one-pot melt processing without solvent to address this key process. By adjusting the molar ratio of PEO-b-PA to lithium bis(trifluoromethanesulphonyl)imide (ethylene oxide:Li = 6:1) and adding 20 wt.% succinonitrile, fast Li⁺ transport channel is conducted within the homogeneous polymer electrolyte, which enables its application at ultra-low temperature (−20 to 25 °C). The composite solid-state electrolyte utilizes dynamic hydrogen-bonding domains and ion-conducting domains to achieve a low interfacial charge transfer resistance (<600 Ω) at −20 °C and high ionic conductivity (25 °C, 3.7 × 10⁻⁴ S cm⁻¹). As a result, the LiFePO₄|Li battery based on composite electrolyte exhibits outstanding electrochemical performance with 81.5% capacity retention after 1200 cycles at −20 °C and high discharge specific capacities of 141.1 mAh g⁻¹ with high loading (16.1 mg cm⁻²) at 25 °C. Moreover, the solid-state SNCM811|Li cell achieves excellent safety performance under nail penetration test, showing great promise for practical application.