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Developing laminar composite solid electrolyte with ultrathin thickness and continuous conduction channels in vertical direction holds great promise for all‐solid‐state lithium batteries. Herein, a thin, laminar solid electrolyte is synthesized by filtrating –NH2 functionalized metal‐organic framework nanosheets and then being threaded with poly(ethylene oxide) chains induced by the hydrogen‐bonding interaction from –NH2 groups. It is demonstrated that the threaded poly(ethylene oxide) chains lock the adjacent metal‐organic framework nanosheets, giving highly enhanced structural stability (Young's modulus, 1.3 GPa) to 7.5‐μm‐thick laminar composite solid electrolyte. Importantly, these poly(ethylene oxide) chains with stretching structure serve as continuous conduction pathways along the chains in pores. It makes the non‐conduction laminar metal‐organic framework electrolyte highly conductive: 3.97 × 10−5 S cm−1 at 25 °C, which is even over 25 times higher than that of pure poly(ethylene oxide) electrolyte. The assembled lithium cell, thus, acquires superior cycling stability, initial discharge capacity (148 mAh g−1 at 0.5 C and 60 °C), and retention (94% after 150 cycles). Besides, the pore size of nanosheet is tailored (24.5–40.9 Å) to evaluate the mechanisms of chain conformation and ion transport in confined space. It shows that the confined pore only with proper size could facilitate the stretching of poly(ethylene oxide) chains, and meanwhile inhibit their disorder degree. Specifically, the pore size of 33.8 Å shows optimized confinement effect with trans‐poly(ethylene oxide) and cis‐poly(ethylene oxide) conformation, which offers great significance in ion conduction. Our design of poly(ethylene oxide)‐threaded architecture provides a platform and paves a way to the rational design of next‐generation high‐performance porous electrolytes. [ABSTRACT FROM AUTHOR]

Inorganic superionic conductor holds great promise for high‐performance all‐solid‐state lithium batteries. However, the ionic conductivity of traditional inorganic solid electrolytes (ISEs) is always unsatisfactory owing to the grain boundary resistance and large thickness. Here, a 13 μm‐thick laminar framework with ≈1.3 nm interlayer channels is fabricated by self‐assembling rigid, hydrophilic vermiculite (Vr) nanosheets. Then, Li0.33La0.557TiO3 (LLTO) precursors are impregnated in interlayer channels and afterwards in situ sintered to large‐size, oriented, and defect‐free LLTO crystal. We demonstrate that the confinement effect permits ordered arrangement of LLTO crystal along the c‐axis (the fastest Li+ transfer direction), permitting the resultant 15 μm‐thick Vr‐LLTO electrolyte an ionic conductivity of 8.22×10−5 S cm−1 and conductance of 87.2 mS at 30 °C. These values are several times' higher than that of traditional LLTO‐based electrolytes. Moreover, Vr‐LLTO electrolyte has a compressive modulus of 1.24 GPa. Excellent cycling performance is demonstrated with all‐solid‐state Li/LiFePO4 battery. [ABSTRACT FROM AUTHOR]

[Display omitted] • LLZO nanosheets with lateral size of 3–5 μm and thickness of ~4.5 nm are synthesized. • LLZO laminar inorganic solid electrolyte with thickness of 12 μm is fabricated. • Ultrahigh ionic conductance of 0.17 S and energy density of 340 Wh kg−1 are achieved. • The compressive strength of LLZO laminar electrolyte reaches 3.2 GPa. • A superior cell performance of 143.2 mAh g−1 after 200 cycles is obtained. The development of thin solid-state electrolytes with high ionic conductivity and mechanical strength is essential for high-performance all-solid-state lithium batteries. Although Inorganic solid electrolytes (ISEs) possess high ionic conductivity, fabricating thin and mechanically stable ISEs is still challenging. Herein, Li 7 La 3 Zr 2 O 12 (LLZO) nanosheets with lateral size of 3–5 μm and thickness of ~4.5 nm were prepared, and then self-assembled into thin, defect-free, and freestanding LLZO laminar ISE (LLISE). Compared to LLZO pellet (>200 μm) obtained by cold-pressing method, LLISE with a thickness of 12 μm attains an almost 10-times higher ionic conductivity of 1.30 × 10−4 S cm−1 at 30 °C because of the short Li-ion diffusion distance. Importantly, this thin thickness gives high ionic conductance (0.17 S at 30 °C) and energy density of 340 Wh kg−1, ranking one of the highest values among reported solid-state electrolytes. Meanwhile, the compressive strength of LLISE with a thickness of 20 μm (LLISE-20) reaches 3.2 Gpa. The Li symmetrical cell assembled with LLISE-20 can work over 1500 h without obvious polarization under a current density of 0.2 mA cm−2 at 60 °C. The LFP/Li cell exhibits superior cycling stability of 143.2 mAh g−1 at 0.5C and 60 °C after 200 cycles with low capacity decay of 0.05% per cycle. [ABSTRACT FROM AUTHOR]

Garnet-type oxide Li 7 La 3 Zr 2 O 12 (LLZO) has attracted considerable attention as promising solid-state electrolyte (SSE) owing to the exceptional bulk ion conduction. However, the Li+ transfer capacity of most LLZO-based solid electrolytes remains inadequate, primarily due to the presence of extensive grain boundaries and excessive thickness. Herein, we report the fabrication of a LLZO-based lamellar composite inorganic solid electrolyte (LLZO/LIC LISE) by in-situ sintering Li 3 InCl 6 (LIC) in LLZO lamellar framework. LIC can act as an effective Li+-conductive grain boundary modifier within the electrolyte, leading to a remarkable reduction in grain boundary resistance of LLZO/LIC LISE (<9.2 Ω cm2), which is much lower than that of LLZO lamellar framework (827.2 Ω cm2). Together with the reduced internal grain boundary of LLZO nanosheet, a high ionic conductivity of 3.22 × 10−4 S cm−1 at 25 °C is obtained for LLZO/LIC LISE. In addition, combining with the thin thickness of 29 μm, LLZO/LIC LISE obtains high ionic conductance of 223 mS and exceptional energy density of 246 Wh kg−1, surpassing most developed SSEs. As a result, the cell assembled with LLZO/LIC LISE achieves superior cycling performance of 144.2 mAh g−1 after 200 cycles at 0.5C with a capacity decay of only 0.055% per cycle. This study may present a facile approach to effectively eliminate the grain boundary resistance of inorganic solid electrolytes toward high-performance all-solid-state lithium batteries. [Display omitted] • A 29 μm-thick LLZO/LIC lamellar composite solid electrolyte is fabricated. • The presence of LIC imparts ultralow grain boundary resistance (<9.2 Ω cm2). • The interfacial interaction between LLZO and LIC improves electrolyte stability. • The thin thickness affords high ionic conductance and energy density. • Superior performance with capacity of 144.2 mA h g−1 after 200 cycles is attained. [ABSTRACT FROM AUTHOR]

Inorganic superionic conductors hold great promise for all-solid-state lithium battery. However, the ionic conductivity of developed inorganic solid electrolytes (ISEs) is often insufficient owing to the enormous grain boundary resistance and large thickness. Herein, a 30 μm-thick Li 7 La 3 Zr 2 O 12 (LLZO) lamellar inorganic solid electrolyte (LLZO/CN LISE) is fabricated by assembling LLZO nanosheets into lamellar framework, followed by in-situ growing g-C 3 N 4 in the interlayer spacing. Based on the regular and unambiguous lamellar structure, g-C 3 N 4 is found to be an ideal grain boundary modifier, and the Li-ion transfer process at grain boundary is thus investigated in detail. We demonstrate that this LLZO/CN LISE achieves an ultralow grain boundary resistance (<12.3 Ω cm2 vs. 1608 Ω cm2 for LLZO pellet) and hence high ionic conduction properties (the ionic conductivity is 2.50 × 10−4 S cm−1 and the ionic conductance is 167 mS at 25 °C). The assembled Li symmetrical cell can stably cycle over 1500 h at 0.2 mA cm−2 and 60 °C. The assembled LiFePO 4 |Li cell also exhibits excellent cycling performances with a discharge capacity of 147.7 mAh g−1 at 0.5C and 60 °C after 150 cycles. This insight should present new opportunities in designing and developing high-performance ISEs. [Display omitted] • A 30 μm-thick Li 7 La 3 Zr 2 O 12 /g-C 3 N 4 lamellar inorganic solid electrolyte is prepared. • High ionic conductivity of 0.25 mS cm−1 and ionic conductance of 167 mS are gained. • The lamellar inorganic solid electrolyte exhibits an elastic modulus of 3.06 GPa. • With LiFePO 4 cathode, the energy densities reach 236 Wh kg−1. • A superior cell performance of 147.7 mAh g−1 after 150 cycles is obtained. [ABSTRACT FROM AUTHOR]

[Display omitted] • Well-ordered vertical Li 7 La 3 Zr 2 O 12 sheet arrays are prepared. • An 8 μm-thick trilayer composite solid electrolyte with sheet arrays is fabricated. • Ultrahigh ionic conductance of 0.5 S and Young's modulus of 1.43 GPa are achieved. • Superior cycling behavior at low N/P ratio (80% retention at 158 cycles) is obtained. • The energy density of NCM/Li cell reaches 458.4 Wh kg−1. To achieve high energy density of all-solid-state lithium batteries, solid-state electrolytes (SSEs) are required to be thin and highly conductive. Although constructing efficient inorganic Li-ion transfer network can provide excellent conductivity for SSEs, it is still challenging for these SSEs to simultaneously realize thin thickness and mechanical stability. Herein, well-ordered vertical Li 7 La 3 Zr 2 O 12 sheet arrays (VLSA) were prepared, followed by introducing triple-layer ion-conducting polymers to fabricate 8 μm-thick VLSA composite solid electrolyte (CSE). We demonstrate that vertical and short VLSA (major path, accounting for 71.4% of Li-ion transfer) and VLSA/polymer interface (minor path, 27.8%) contribute to the high ionic conductivity of 2.60 × 10−4 S cm−1 and ionic conductance of 0.5 S at 30 °C, ranking one of the highest values among reported SSEs. The stiff VLSA enhances the mechanical strength of CSE, while the polymer existing in VLSA channels serves as a deformable buffer, endowing CSE with bendable property. Besides, the trilayer polymer structure permits this electrolyte to be compatible with lithium anode and high-voltage cathode. Therefore, the high-loading LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) cell can be cycled with limited lithium anode (N/P ratio = 1.18) over 158 cycles with capacity retention upon 80%, realizing a high energy density of 458.4 Wh kg−1. [ABSTRACT FROM AUTHOR]

Inorganic superionic conductor has been widely studied for potential application in all-solid-state lithium battery due to its high bulk ionic conductivity. However, the large grain boundary resistance and large thickness resulted from the poor film-forming ability, restricting its actual ionic conductivity. Inspired by the excellent film-forming ability and ultrathin thickness of 2D lamellar membrane, we reported an 11 μm-thick MOF lamellar membrane derived LLTO electrolyte (MLLTO). The electrolyte is prepared by impregnating LLTO precursors into the pores and interlayer channels of MOF lamellar membrane, followed by in situ sintering. It is demonstrated that the confined effect of interlayer channel in MOF lamellar membrane regulates the growth and arrangement of LLTO crystal, affording reduced grain boundary resistance. The porous structure of MOF nanosheet permits the construction of vertical Li+ transfer pathways between adjacent layers. Finally, MLLTO achieves a high ionic conductivity of 1.19 × 10−4 S cm−1 and ionic conductance of 0.215 S at room temperature, much higher than those of conventional LLTO electrolytes. The Li/MLLTO/Li symmetrical cell can stably cycle for 1000 h from 0.1 to 0.4 mA cm−2 at 60 °C without obvious polarization. The LFP/Li battery displays discharge capacity of 149.6 mAh g−1 at 0.5C after 200 cycles with low capacity decay of 0.04% per cycle. [Display omitted] • A thin MOF lamellar membrane derived LLTO electrolyte (MLLTO, 11 μm) is prepared. • Grain boundary resistance is reduced by controlling crystal growth and arrangement. • The porous structure of MOF permits the construction of vertical transfer pathways. • The ionic conductivity of MLLTO reaches 1.19 × 10−4 S cm−1 at room temperature. • Ultrahigh ionic conductance of 0.215 S is obtained due to the thin thickness. [ABSTRACT FROM AUTHOR]

• Thin solid electrolyte based on Vr-LLTO framework and permeated PEO is prepared. • LLTO crystals act as low-barrier Li+ conduction highways along Vr nanosheet surface. • High Li+ conduction property (1.04 × 10−4 s cm−1 at 25 °C and 67.45 mS) is achieved. • The covalently-bonded structure permits electrolyte superior structure stability. • Expected cell performances (e.g. low capacity decay after 200 cycles) are achieved. Inorganic superionic conductors hold great promise for all-solid-state lithium batteries because of their superior ionic conductivity. However, their application as electrolytes is limited by the trade-off between ion conduction and stability. Here, a thin composite solid electrolyte, vermiculite-Li 0.33 La 0.557 TiO 3 /poly(ethylene oxide) (Vr-LLTO/PEO), is prepared by in-situ co-sintering an interconnected Vr-LLTO framework and then impregnating PEO. Within this electrolyte, the continuous LLTO on Vr nanosheet surface acts as efficient pathways for vertical Li+ transfer with reduced grain boundary resistance. Together with the thin thickness (35 μm), Vr-LLTO/PEO electrolyte attains the ionic conductivity as high as 1.04 × 10−4 S cm−1 at 25 °C, over three times that of LLTO pellet and surpassing that of most reported ceramic electrolytes. Furthermore, the disordered stacked Vr nanosheets in framework are covalently linked by LLTO, together with the flexible PEO matrix, achieving highly enhanced structural stability with compressive strength of 319 MPa. In this manner, the trade-off between ion conduction and stability is overcome, which allows the assembled LiFePO 4 /Li cell achieving satisfactory cycling performances: an initial discharge capacity of 150.3 mAh g −1 at 1 C and capacity decay of only 0.08% per cycle after 200 cycles. This study may inspire insights into the subtle design of conductive and stable electrolytes for high-performance devices. [Display omitted] [ABSTRACT FROM AUTHOR]

• A flexible, ion-conducting PEO-LLTO framework solid electrolyte is prepared. • The vertically bicontinuous transfer channels act as Li+ conduction highways. • Ultrahigh ionic conductivity (2.04 × 10−4 S cm−1 at 25 °C) is achieved. • The interconnected network offers PLLF electrolyte excellent structural stability. • Superior cell performances (~97.2% retention after 150 cycles) are achieved. All-solid-state lithium batteries, featuring high security and volume energy density, hold great potential as next-generation energy storage device. However, their development needs the fabrication of ionic conductive and structural stable solid electrolyte. Herein, Li 0.33 La 0.557 TiO 3 (LLTO) framework with interlocked porous structure is synthesized by sintering the gel permeated nylon. Then, poly(ethylene oxide) (PEO) is incorporated in the pores to produce PEO-LLTO framework solid electrolyte (PLLF electrolyte) with vertically bicontinuous phase. We demonstrate that LLTO framework fast transports Li+ through the intrinsic vacancy; meanwhile the confined PEO with low crystallization displays fast Li+ transfer ability, thus synergistically realizing efficient Li+ conduction. This novel PLLF electrolyte exhibits a remarkable ionic conductivity of 2.04 × 10−4 S cm−1, which is ~72 times higher than that of traditional PEO-based electrolytes and superior to most reported solid electrolytes. Moreover, the interconnected networks endow PLLF electrolyte with excellent structural stability. Thus, the LiFePO 4 (LFP)/Li cell exhibits extraordinary cycling stability: the discharge capacity of 154.7 mAh g−1 at 1 C after 150 cycles with capacity decay of only 0.03% per cycle. Briefly, such a vertically bicontinuous phase structure maximizes the cooperation between the conduction function of ceramic framework and the stability of polymer, offering a promising approach for all-solid-state batteries. [ABSTRACT FROM AUTHOR]

Solid-state polymer electrolytes (SPEs) show great potential owing to inherent flexibility and safety but limited by the low ionic conductivity. Herein, poly (ethylene glycol) grafted polymer-like quantum dots (PPQDs) with average diameter of ~2.5 nm and abundant conduction groups are synthesized as nanofillers for hybrid polymer electrolytes. The functionalization of poly (ethylene glycol) provides abundant Li+ transfer sites and meanwhile enhances the compatibility between PPQDs and poly (ethylene oxide) (PEO). Accordingly, these PPQDs uniformly disperse and form rich networks with PEO chains to effectively reduce the crystallinity of PEO and promote the dissociation of lithium salts, different from large-size or inorganic fillers. Consequently, efficient ion-conductive networks are constructed by PPQDs and PEO for vertical Li+ conduction: 5.53 × 10−5 S cm−1 at 30 °C, 16 times higher than that of PEO electrolyte. Furthermore, the hydrogen-bonding interactions at PPQD-PEO interfaces afford excellent stability and flexibility to electrolytes. And superior cycling performance of ~146 mAh g−1 after 150 cycles at 1.0C with capacity decay of 0.046% per cycle is therefore achieved. Compared with traditional fillers, PPQDs with inherent advantages, i.e. , molecular-level size and designable groups, endow hybrid electrolytes with dramatically enhanced ion conduction and stability, manifesting great potential for all-solid-state lithium batteries. Image 1 • Molecular-scale PPQDs are synthesized to hybridize polymer electrolytes. • Rich PPQD-PEO interfaces and continuous vertical transfer networks are constructed. • PPQDs offer 16 times' increase on ionic conductivity to the hybrid electrolyte. • Hydrogen interactions at PPQD-PEO interfaces afford excellent structural stability. • Superior battery performances (~146 mAh g−1 after 150 cycles at 1C) are achieved. [ABSTRACT FROM AUTHOR]