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A vital approach to accessing high‐safety and high‐energy‐density lithium batteries is to develop solid‐state electrolytes (SSEs) instead of liquid electrolytes. However, lithium‐ion transport and interface stability issues puzzle the construction of solid‐state lithium batteries (SSLBs). Thus, developing fast‐ionic conductors with high electrochemical performances and chemical stability is crucial to SSLBs. Nanowires (NWs) possess high aspect ratios for maintaining carrier transport along the radial direction, thus being extensively employed in SSLBs for the enhancement of ion transport efficiency, mechanical properties, thermostability, flame retardancy, and interface stability between electrodes and electrolytes, consequently boosting the cycle stability and safety of SSLBs. In this work, the advances in NWs for SSLBs, from rational design and synthesis strategies to applications in composite cathodes, anode materials, and SSEs of SSLBs, are systematically reviewed. The key role of NWs in electrodes and the enhancement mechanism of SSE performance by introducing NWs are concluded in detail. Finally, the existing challenges and anticipated prospects for the future development of advanced nanowire‐based SSLBs are summarized and demonstrated. This review aims to provide a comprehensive understanding to facilitate the application of NWs in SSLBs. [ABSTRACT FROM AUTHOR]

Lithium–Sulfur (Li─S) batteries are renowned for their high theoretical specific capacity and cost‐effectiveness. Nevertheless, their performance could be impeded by obstacles including lithium dendrite growth and lithium polysulfide (LiPS) shuttle, particularly under harsh conditions. Herein, an economical strategy is reported for modifying polyolefin separators (PP) with covalent organic polymer networks (TPE) to alter Li solvent structure, enhance lithium‐ion transport, and suppress shuttle effects. Combining in situ/ex situ characterization and theoretical calculations, it is demonstrated that the lithiophilic groups (‐C═N‐) in the TPE@PP separator form strong interaction with lithium, facilitating the dissociation of Li─Solvent/LiPS‐solvent to release freer lithium ion and shape a stable solid electrolyte interface rich in LiF and Li3N. The polymer network serves as a "highway" that accelerates Li transport and promotes uniform nucleation behavior. Therefore, the Li|TPE@PP|CNT/S cell enables 60% capacity retention after 2000 cycles at 1.0 C and exhibits stable cycling performance of 100 cycles from ‐40 to 80 °C. Moreover, the pouch cell maintains a capacity of more than 600 mA h g−1 after 30 cycles at 0 °C. This study provides a promising avenue for the application of high‐performance batteries in harsh environment from the perspective of separator engineering. [ABSTRACT FROM AUTHOR]

Fully solid-state lithium-ion cells have the benefits of excellent safety, remarkable electrochemical stability, and extended cycle life. They are categorized as prospective candidates for new-generation energy storage devices capable of safe and stable operation for relatively long periods. In whole solid-state Li-ion cells, polymer-based solid electrolyte membranes (SEMs) are expected to serve as both the solid electrolyte and the partition material. Remarkably high ionic conductivity and efficient ion diffusion can be achieved in SEMs by incorporating inorganic filler materials. In the present work, solid electrolyte membranes are developed by a simple solution cast method. The addition of Al2O3 nanoparticles is found to enhance the ionic conductivity of SE membranes to 1.25 × 10−4 S cm−1 for optimum concentrations of lithium salt and filler material. These SE membranes show relatively high electrochemical stability window up to 4.75 V. Transparent and freestanding SE membranes developed using PEO-PVDF-LiNO3-Al2O3 have excellent thermal stability, ideal ion transport number, and good electrochemical properties, suitable for applications in solid-state lithium-ion cells. Assembled LiFePO4-MWCNT//SEM//Li metal half-cells are found to deliver an initial discharge capacity of 128 mAh g−1 at 0.1 C and an initial Coulombic efficiency of 98%. [ABSTRACT FROM AUTHOR]

[Display omitted] The electrolytes with high lithium-ion transference number (t Li+) can reduce the formation of concentration polarization during charge/discharge process and improve the electrochemical performance of lithium-ion batteries (LIBs). Herein, we report triblock copolymer electrolytes (PBOEE) containing borate. The sp2 hybridized boron atoms acting as Lewis acids can anchor the anions of lithium salts, enabling PBOEE to achieve high t Li+ of up to 0.53. Also, the borate groups can promote the formation of stable organic-rich solid electrolyte interphase (SEI) film, which enables the Li symmetric cell to cycle stably at 0.1 mA cm−2/0.1 mAh cm−2 for more than 3100 h with a low overpotential of 0.08 V under 50 °C. The optimized PBOEE_24 has an ionic conductivity of 1.41 × 10−4 S cm−1 and electrochemical stability window of 4.8 V vs. Li+/Li at 50 °C. Combining these advantages, the LiFePO 4 /PBOEE_24/Li cell exhibits an initial discharge specific capacity of 157.3 mA h g−1 at 0.5C with a capacity retention of 85 % after 600 cycles under 50 °C. At a higher current density of 1C, the discharge capacity maintains at 128.0 mA h g−1 after 400 cycles with a capacity retention of 84.88 %. These results suggest that block copolymer containing sp2 hybridized boron atoms is a promising all-solid-state polymer electrolyte. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs)‐incorporated solid‐state polymer electrolytes (iono‐SPEs) have high ionic conductivities but show non‐uniform Li+ transport in different phases. This work greatly promotes Li+ transport in polymer phases by employing a poly (vinylidene fluoride‐trifluoroethylene‐chlorotrifluoroethylene) [P(VDF‐TrFE‐CTFE), PTC] as the framework of ILs to prepare iono‐SPEs. Unlike PVDF, PTC with suitable polarity shows weaker adsorption energy on IL cations, reducing their possibility of occupying Li+‐hopping sites. The significantly higher dielectric constant of PTC than PVDF facilitates the dissociation of Li‐anions clusters. These two factors motivate Li+ transport along PTC chains, narrowing the difference in Li+ transport among varied phases. The LiFePO4/PTC iono‐SPE/Li cells cycle steadily with capacity retention of 91.5 % after 1000 cycles at 1 C and 25 °C. This work paves a new way to induce uniform Li+ flux in iono‐SPEs through polarity and dielectric design of polymer matrix. [ABSTRACT FROM AUTHOR]

High‐frequency actuators are reported based on non‐flammable lithium‐ion conducting phosphate liquid crystal–polymer composite electrolytes, which exhibit a bending response at frequencies up to 80 Hz under an AC voltage of 2 V, owing to its high ionic conductivity reaching 10−4 S cm−1 at room temperature. An equimolar complex of a phosphate‐containing mesogenic molecule and lithium bis(trifluoromethylsulfonyl)imide through the ion‐dipole interactions induced a room‐temperature smectic A liquid‐crystalline (LC) phase forming 2D ion‐transport pathways comprising the 2D array of the phosphate moieties. A blend of 80 wt% LC electrolyte and 20 wt% polymers (poly(vinyl chloride) and poly(vinylidene fluoride‐co‐hexafluoropropylene)) formed a flexible, mechanically robust LC–polymer composite film. Scanning electron microscopy and white light interference microscopy revealed a microphase‐segregated structure consisting of a continuous LC phase and a porous polymer matrix. In addition, the continuity of porous structure across the film is confirmed by permeation experiments of solvents thorough the membrane with a homemade filter in a dead‐end filtration mode. The LC–polymer composite film sandwiched between two poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonic acid) electrodes is found to simultaneously exhibit high bending strain (0.63%) and high output force (0.35 mN), owing to the high ion migration into the composite electrolyte and electrode. [ABSTRACT FROM AUTHOR]

The rapid development of the electronics market necessitates energy storage devices characterized by high energy density and capacity, alongside the ability to maintain stable and safe operation under harsh conditions, particularly elevated temperatures. In this study, a semi-solid-state electrolyte (SSSE) for Li-metal batteries (LMB) is synthesized by integrating metal-organic frameworks (MOFs) as host materials featuring a hierarchical pore structure. A trace amount of liquid electrolyte (LE) is entrapped within these pores through electrochemical activation. These findings demonstrate that this structure exhibits outstanding properties, including remarkably high thermal stability, an extended electrochemical window (5.25 V vs Li/Li + ), and robust lithium-ion conductivity (2.04 × 10 -4  S cm -1 ), owing to the synergistic effect of the hierarchical MOF pores facilitating the storage and transport of Li ions. The Li//LiFePO 4 cell incorporating prepared SSSE shows excellent capacity retention, retaining 97% (162.8 mAh g -1 ) of their initial capacity after 100 cycles at 1 C rate at an extremely high temperature of 95 °C. It is believed that this study not only advances the understanding of ion transport in MOF-based SSSE but also significantly contributes to the development of LMB capable of stable and safe operation even under extremely high temperatures., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

The localisation and quantitative analysis of lithium (Li) in battery materials, components, and full cells are scientifically highly relevant, yet challenging tasks. The methodical developments of MeV ion beam analysis (IBA) presented here open up new possibilities for simultaneous elemental quantification and localisation of light and heavy elements in Li and other batteries. It describes the technical prerequisites and limitations of using IBA to analyse and solve current challenges with the example of Li-ion and solid-state battery-related research and development. Here, nuclear reaction analysis and Rutherford backscattering spectrometry can provide spatial resolutions down to 70 nm and 1% accuracy. To demonstrate the new insights to be gained by IBA, SiOx-containing graphite anodes are lithiated to six states-of-charge (SoC) between 0–50%. The quantitative Li depth profiling of the anodes shows a linear increase of the Li concentration with SoC and a match of injected and detected Li-ions. This unambiguously proofs the electrochemical activity of Si. Already at 50% SoC, we derive C/Li = 5.4 (< LiC6) when neglecting Si, proving a relevant uptake of Li by the 8 atom % Si (C/Si ≈ 9) in the anode with Li/Si ≤ 1.8 in this case. Extrapolations to full lithiation show a maximum of Li/Si = 1.04 ± 0.05. The analysis reveals all element concentrations are constant over the anode thickness of 44 µm, except for a ~6-µm-thick separator-side surface layer. Here, the Li and Si concentrations are a factor 1.23 higher compared to the bulk for all SoC, indicating preferential Li binding to SiOx. These insights are so far not accessible with conventional analysis methods and are a first important step towards in-depth knowledge of quantitative Li distributions on the component level and a further application of IBA in the battery community. [ABSTRACT FROM AUTHOR]

Abstract LiNi0.8Co0.15Al0.05O2 (NCA) secondary particles with high tap density have a great potential for high volumetric energy density lithium (Li)‐ion power battery. However, the ionic conductivity mechanism of NCA with compact structure is still a suspense, especially the function of grain boundaries. Herein, we systematically investigate the Li‐ion transport behavior in both the primitive NCA (PNCA) secondary sphere densely grown by single‐crystal primary grains and ball‐milled NCA (MNCA) nanosized particle to reveal the role of grain boundaries for Li‐ion transport. The PNCA and MNCA have comparable Li‐ion diffusion coefficients and rate performance. Moreover, the graphene nanosheet conductive additive only mildly affects the Li‐ion diffusion in PNCA cathode, while which severely blocks the Li‐ion transport in MNCA cathode. Through high‐resolution transmission electron microscopy and electron energy loss spectroscopy, we clearly observe Li‐ion depletion at lower state of charge (SOC) and Li‐ion aggregation at high SOC along the grain boundaries of PNCA secondary particles during high‐rate lithiation process. The grain boundaries can construct an interconnected Li‐ion transport network for highly efficient Li‐ion transport, which contributes to excellent high‐rate performance of compact PNCA secondary particles. These findings present new strategy and deep insight in designing compact materials with excellent high‐rate performance.

Herein, we demonstrate a novel and feasible strategy to stabilize the LiNi 0.83 Co 0.12 Mn 0.05 O 2 (NCM) structure via the in-situ formation of a superficial spinel layer with potassium (K) doping. While K+ doped NCM is not new, the formation of the protective spinel layer gives surprising results with even a trace amount of doping, which is unique and novel, and nowhere reported. The structural transformation from layered to spinel on the surface region of NCM is achieved with a K-doping level of 0.05 mol% (NCM-0.05K) and the formed spinel layer acted as a protective pillar for stabilizing the host structure, leading to substantially improved electrochemical performance. The X-ray photoelectron spectra demonstrate a large increase in nickel (Ni2+) distribution after cycling for pristine but almost no change for the NCM-0.05K, suggesting a stable preformed spinel layer. The above results reveal that the K+ doping can strongly reduce the Ni4+ to stable Ni2+ under the spinel phase formation and improves cell performances in terms of specific capacity, capacity retention, rate capability, and Li+ diffusivity. The internal micro-cracking of host NCM is also effectively suppressed by the low amount of K doping. Excessive K-doping, in contrast, leads to a reduction in (de)lithiation rate and greater polarization. • An in-situ formation of a passive spinel layer through a trace amount of K+ doping. • K+-doping improves the structure stability of the Ni-rich NCM. • K-NCM shows excellent Li+-diffusive properties than pristine-NCM. • K-NCM also suppresses the internal micro-cracking. [ABSTRACT FROM AUTHOR]

The addition of filler particles to polymer electrolytes is known to increment their ionic conductivity (IC). A detailed understanding of how the interactions between the constituent materials are responsible for the enhancement remains to be developed. A significant contribution is ascribed to an increment of the polymer amorphous fraction, induced by the fillers, resulting in the formation of higher ionic conductivity channels in the polymer matrix. However, the dependence of IC on the particle weight load and its composition on the polymer morphology is not fully understood. This work investigates Li-ion transport in composite polymer electrolytes (CPE) comprising Bi-doped LLZO particles embedded in PEO:LiTFSI matrixes. We find that the IC optimizes for very low particle weight loads (5–10%) and that both its magnitude and the load are required, strongly dependent on the garnet particle composition. Based on structural characterization results and electrochemical impedance spectroscopy, a mechanism is proposed to explain these findings. It is suggested that the Li-molar content in the garnet particle controls its interactions with the polymer matrix, resulting at the optimum loads reported, in the formation of high ionic conductivity channels. We propose that filler particle chemical manipulation of the polymer morphology is a promising avenue for the further development of composite polymer electrolytes. [ABSTRACT FROM AUTHOR]

We present the development of free-standing ionic liquid crystal-polymer composite electrolyte films aimed at achieving high-frequency response electromechanical actuators. Our approach entails designing novel layered ionic liquid-crystalline (LC) assemblies by complexing a mesomorphic dimethylphosphate with either a lithium salt or a room-temperature ionic liquid through the formation of ion-dipole interactions or hydrogen bonds. These electrolytes, exhibiting room-temperature ionic conductivities on the order of 10 -4 S cm -1 and wide LC temperature ranges up to 77 °C, were successfully integrated into porous polymer networks. We systematically investigated the impact of ions and electrodes on the performance of ionic electroactive actuators. Specifically, the Li + -based liquid crystal-polymer composite actuator with PEDOT:PSS electrodes demonstrated the highest bending deformation, achieving a strain of 0.68% and exhibiting a broad frequency response up to 110 Hz, with a peak-to-peak displacement of 3 μm. In contrast, the ionic-liquid-based liquid crystal-polymer composite actuator with active carbon electrodes showcased a bending response at a maximum frequency of 50 Hz and a force generation of 0.48 mN, without exhibiting the back relaxation phenomenon. These findings offer valuable insights for advancing high-performance electromechanical systems with applications ranging from soft robotics to haptic interfaces.

All-solid-state lithium metal batteries can address crucial challenges regarding insufficient battery cycling life and energy density. The demonstration of long-cycling dendrite-free all-solid-state lithium metal batteries requires precise tailoring of lithium-ion transport of solid-state electrolytes (SSEs). In this work, a proof of concept is reported for precise tailoring of lithium-ion transport of a halide SSE, Li 3 InCl 6 , including intragranular (within grains) but also intergranular (between grains) lithium-ion transport. Lithium-ion migration tailoring mechanism in crystals is developed by unexpected enhanced Li, In, and Cl vacancy populations and lower energy barrier for hopping. The lithium-ion transport tailoring mechanism between the grains is determined by the elimination of voids between grains and the formation of unexpected supersonic conducting grain boundaries, boosting the lithium dendrite suppression ability of SSE. Due to boosted lithium-ion conduction and dendrite-suppression ability, the all-solid-state lithium metal batteries coupled with Ni-rich LiNi 0.83 Co 0.12 Mn 0.05 O 2 cathodes and lithium metal anodes demonstrate breakthroughs in electrochemical performance by achieving extremely long cycling life at a high current density of 0.5 C (2000 cycles, 93.7% capacity retention). This concept of precise tailoring of lithium-ion transport provides a cost, time, and energy efficient solution to conquer the remaining challenges in all-solid-state lithium-metal batteries for fast developing electric vehicle markets., (© 2023 Wiley‐VCH GmbH.)

The localisation and quantitative analysis of lithium (Li) in battery materials, components, and full cells are scientifically highly relevant, yet challenging tasks. The methodical developments of MeV ion beam analysis (IBA) presented here open up new possibilities for simultaneous elemental quantification and localisation of light and heavy elements in Li and other batteries. It describes the technical prerequisites and limitations of using IBA to analyse and solve current challenges with the example of Li-ion and solid-state battery-related research and development. Here, nuclear reaction analysis and Rutherford backscattering spectrometry can provide spatial resolutions down to 70 nm and 1% accuracy. To demonstrate the new insights to be gained by IBA, SiOx-containing graphite anodes are lithiated to six states-of-charge (SoC) between 0–50%. The quantitative Li depth profiling of the anodes shows a linear increase of the Li concentration with SoC and a match of injected and detected Li-ions. This unambiguously proofs the electrochemical activity of Si. Already at 50% SoC, we derive C/Li = 5.4 (< LiC6) when neglecting Si, proving a relevant uptake of Li by the 8 atom % Si (C/Si ≈ 9) in the anode with Li/Si ≤ 1.8 in this case. Extrapolations to full lithiation show a maximum of Li/Si = 1.04 ± 0.05. The analysis reveals all element concentrations are constant over the anode thickness of 44 µm, except for a ~6-µm-thick separator-side surface layer. Here, the Li and Si concentrations are a factor 1.23 higher compared to the bulk for all SoC, indicating preferential Li binding to SiOx. These insights are so far not accessible with conventional analysis methods and are a first important step towards in-depth knowledge of quantitative Li distributions on the component level and a further application of IBA in the battery community.

All-solid-state batteries (ASSBs) are gaining traction in the arena of energy storage due to their promising results in producing high energy density and long cycle life coupled with their capability of being safe. The key challenges facing ASSBs are low conductivity and slow charge transfer kinetics at the interface between the electrode and the solid electrolyte. Garnet solid-state electrolyte has shown promising results in improving the ion conductivity but still suffers from poor capacity retention and rate performance due to the interfacial resistance between the electrodes. To improve the interfacial resistance, we prepared a composite consisting of Li7La2.75Ca0.25Zr1.75Nb0.25O12 (LLCZN) garnet material as the ceramic, polyethylene oxide (PEO) as the polymer, and lithium hexafluorophosphate (LiPF6) as the salt. These compounds are mixed in a stoichiometric ratio and developed into a very thin disc-shaped solid electrolyte. The LLCZN provides a lithium-ion transport path to enhance the lithium-ion conduction during charging and discharging cycles, while the LiPF6 contributes more lithium ions via the transport path. The PEO matrix in the composite material aids in bonding the compounds together and creating a large contact area, thereby reducing the issue of large interfacial resistance. FESEM images show the porous nature of the electrolyte which promotes the movement of lithium ions through the electrolyte. The fabricated LLCZN/PEO/LiPF6 solid-state electrolyte shows outstanding electrochemical stability that remains at 130 mAh g−1 up to 150 charging and discharging cycles at 0.05 mA cm−2 current. All the specific capacities were calculated based on the mass of the cathode material (LiCoO2). In addition, the coin cell retains 85% discharge capacity up to 150 cycles with a Coulombic efficiency of approximately 98% and energy efficiency of 90% during the entire cycling process.

To prevent global warming, ESS development is in progress along with the development of electric vehicles and renewable energy. However, the state-of-the-art technology, i.e., lithium-ion batteries, has reached its limitation, and thus the need for high-performance batteries with improved energy and power density is increasing. Lithium-sulfur batteries (LSBs) are attracting enormous attention because of their high theoretical energy density. However, there are technical barriers to its commercialization such as the formation of dendrites on the anode and the shuttle effect of the cathode. To resolve these issues, a boron nitride nanotube (BNNT)-based separator is developed. The BNNT is physically purified so that the purified BNNT (p−BNNT) has a homogeneous pore structure because of random stacking and partial charge on the surface due to the difference of electronegativity between B and N. Compared to the conventional polypropylene (PP) separator, the p−BNNT loaded PP separator prevents the dendrite formation on the Li metal anode, facilitates the ion transfer through the separator, and alleviates the shuttle effect at the cathode. With these effects, the p−BNNT loaded PP separators enable the LSB cells to achieve a specific capacity of 1429 mAh/g, and long-term stability over 200 cycles.

To explore the feasibility and rationality of a hydrogen‐terminated diamond surface film as an solid electrolyte interface (SEI) for lithium‐sulfur batteries, the adsorption and migration behavior of lithium atoms on the hydrogen‐terminated diamond surface with different amounts of hydrogen defects are determined by first‐principles calculations. Since a hydrogen deficiency in the row direction is denser than a hydrogen deficiency in the chain direction, hydrogen deficiency can drive lithium‐ion deposition. Thus, lithium atoms are more stable on the surface of hydrogen‐terminated diamonds with a hydrogen deficiency in the direction of the dimer row. The adsorption of lithium atoms on hydrogen‐terminated diamond films lacking three hydrogens is more stable due to the absence of dangling chemical bonds on the surface of the hydrogen‐terminated diamond. Therefore, lithium atoms cannot be adsorbed on an all‐H‐diamond surface. The low adsorption energy of lithium atoms on a clean diamond surface indicates that it is a simple physical adsorption. H termination increases the adsorption energy and migration activation energy of Li on the diamond surface. H termination changes the migration path of Li on the diamond surface. The atomic deposition of Li is driven by the center of the H defect region on the H‐diamond surface. [ABSTRACT FROM AUTHOR]

• Effect of Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) particle size in composite cathodes was studied. • Smaller LATP particles promote Li+ pathways formation in a composite cathode. • Comprehensive analysis results provide unique insights into the reaction mechanism. Solid electrolytes (SEs) are key materials for all-solid-state lithium-ion batteries (ASSLBs), and are being studied for various applications. Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP), a NASICON-type SE, is noteworthy due to its wide voltage range for cathode operation and economic feasibility. However, fabricating well-contacted interparticle interfaces in composite cathodes using LATP is challenging because of its high grain-boundary resistance. To address this issue, we investigated the correlation between lithium-ion transport in composite cathodes and the particle size of LATP. We successfully synthesized two LATPs with different size distributions and prepared composite cathodes. Performance evaluation and various advanced analyses of composite cathodes were conducted, the results revealed that LATP with a smaller particle-size distribution formed more a uniform Li+ transfer network in the composite cathode than the larger particles, which contributed to the stable and fast electrochemical characteristics of the ASSLB. Additionally, we also observed real-time structural changes during electrochemical reactions in composite cathodes through in situ X-ray diffraction analysis. The results of our comprehensive analysis are expected to provide valuable insights into the reaction mechanisms of LATP-based ASSLBs, as they have not been extensively explored before. [ABSTRACT FROM AUTHOR]

Solid electrolytes are safer alternatives to liquid electrolytes. Adding Ga to lithium lanthanum zirconium oxide (LLZO) garnet-like solid-state electrolytes effectively improves their performance. The properties of solid-state electrolytes prepared using the two mainstream methods, namely, electrospinning and sol-gel, vary and directly affect the electrochemical performance of assembled batteries. In this study, we prepared Li 6.25 Ga 0.25 La 3 Zr 2 O 12 (Ga-LLZO) nanoparticles and nanofibers using the sol-gel and electrospinning methods, respectively. The battery was also assembled with composite film consisting of the poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer substrate within Ga-LLZO ceramic fillers. The electrolyte of the battery prepared by Ga-LLZO nanofibers has better conductivity. We fabricated a Li|10 wt% Ga-LLZO nanofiber/PVDF-HFP/60 wt% lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)|LiFePO 4 button battery using the optimal concentration. The device demonstrated a stable cycle lasting up to 700 h, a Coulombic efficiency of 98%, a capacity retention rate of 96.5%, and an electrochemical window up to 5 V vs Li/Li+ at room temperature. Over time, a suitable contact interface generated a positive feedback loop. The ionic conductivity was 1.1 × 10−4 S·cm−1. The newly prepared electrolyte films aid the fabrication of future solid electrolytes. [Display omitted] • Successful doping of Ga into Li 7 La 3 Zr 2 O 12 to form Li 6.25 Ga 0.25 La 3 Zr 2 O 12. • Ga-LLZO nanofibers demonstrated high crystallinity and conductivity. • High Coulombic efficiency (98%) and capacity retention rate (96.5%) were observed. • Electrochemical stability window of the electrolyte was extended up to 5 V vs Li/Li+. [ABSTRACT FROM AUTHOR]

The safety and cycle life of lithium-ion batteries (LIBs) are largely determined by the solid electrolyte interphase (SEI) formed on the surface of the anode. However, there is still a lack of understanding regarding the structure and properties of the individual SEI components. Among others, lithium oxide (Li 2 O), lithium carbonate (Li 2 CO 3 ), and lithium fluoride (LiF) are known to be the main components of the inorganic SEI layer in conventional LIBs, but their intrinsic protective roles remain controversial. Herein, we present the transformational effects of their amorphous phase on the mechanical and transport characteristics, based on first-principles calculations. Our studies clearly demonstrate that their amorphous phases exhibit significantly improved Li-ion conductivity when compared to the crystalline structures. Additionally, among them, amorphous LiF emerges as a frontrunner for fast Li + ion transportation, reversing the conventionally understood hierarchy. Under ambient conditions, the amorphous phases of LiF, Li 2 O, and Li 2 CO 3 are thermodynamically unstable and tend to undergo recrystallization. However, this work highlights that exceptionally ductile and resilient amorphous phases can form if SEI formation and growth would involve some admixing of lithiophilic impurities like nitrogen (N) within the host matrices.

Lithium metal deposition is strongly affected by the intrinsic properties of the solid-electrolyte interphase (SEI) and working electrolyte, but a relevant understanding is far from complete. Here, by employing multiple electrochemical techniques and the design of SEI and electrolyte, we elucidate the electrochemistry of Li deposition under mass transport control. It is discovered that SEIs with a lower Li ion transference number and/or conductivity induce a distinctive current transition even under moderate potentiostatic polarization, which is associated with the control regime transition of Li ion transport from the SEI to the electrolyte. Furthermore, our findings help reveal the creation of a space-charge layer at the electrode/SEI interface due to the involvement of the diffusion process of Li ions through the SEI, which promotes the formation of dendrite embryos that develop and eventually trigger SEI breakage and the control regime transition of Li ion transport. Our insight into the very initial dendritic growth mechanism offers a bridge toward design and control for superior SEIs.

Abstract: Understanding Li‐ion migration mechanisms and enhancing Li‐ion transport in Li2ZrO3 (LZO) is important to its role as solid absorbent for reversible CO2 capture at elevated temperatures, as ceramic breeder in nuclear reactors, and as electrode coating in high‐voltage lithium‐ion batteries (LIBs). Although defect engineering is an effective way to tune the properties of ceramics, the defect structure of LZO is largely unknown. This study reports the defect structure and electrical properties of undoped LZO and a series of cation‐doped LZOs: (i) depending on their charge states, cation dopants can control the oxygen vacancy concentration in doped LZOs; (ii) the doped LZOs with higher oxygen vacancy concentrations exhibit better Li+ conductivity, and consequently faster high‐temperature CO2 absorption. In fact, the Fe (II)‐doped LZO shows the highest Li‐ion conductivity reported for LZOs, reaching 3.3 mS/cm at ~300°C that is more than 1 order of magnitude higher than that of the undoped LZO. [ABSTRACT FROM AUTHOR]

Achieving low-energy-barrier lithium ion transport is a fundamental issue for composite solid-state electrolytes (CSEs) in all-solid-state lithium metal batteries (ASSLMBs). In this work, a hydrogen bonding induced confinement strategy was proposed to construct confined template channels for low-energy-barrier lithium ion continuous transport. Specifically, the ultrafine boehmite nanowires (BNWs) with 3.7 nm diameter were synthesized and superiorly dispersed in a polymer matrix to form a flexible CSE. The ultrafine BNWs with large specific surface areas and abundant oxygen vacancies assist the dissociation of lithium salts and confine the conformation of polymer chain segments by hydrogen bonding between the BNWs and the polymer matrix, thus forming a polymer/ultrafine nanowire intertwined structure as template channels for dissociated lithium ions continuous transport. As a result, the as-prepared electrolytes displayed a satisfactory ionic conductivity of 0.714 mS cm -1 and low energy barrier (16.30 kJ mol -1 ), and the assembled ASSLMB delivered excellent specific capacity retention (92.8%) after 500 cycles. This work demonstrates a promising way to design CSEs with high ionic conductivity for high-performance ASSLMBs.

Lithium polymer batteries (LPBs) with a high energy density and safety are being actively studied for their use as an energy storage system. However, bottlenecks to their development include charge-transport resistance and poor interfacial contact. In this paper, we introduce carbon nanofiber (CNF) as a conductive additive and the optimization of porosity in the electrode by calendering to realize a high loading density LPB. A simple dispersion strategy is applied to homogeneously disperse nanofiber additives in the electrode to achieve high electronic conductivity. Calendering with optimized pressing degree was performed on the CNF-based electrode to enhance lithium-ion transport and electron conduction in the LPB. The optimal pressing conditions were confirmed by measuring the electronic conductivity, internal resistance, lithium-ion diffusion coefficient, and charge transport characteristics of the cells. When the electrode was pressed by 35%, optimum electrode wettability by solid polymer electrolyte and contact between particles and current collector were achieved, resulting in the high performance of the LPB. Finally, at the optimized pressing degree, we successfully demonstrate 90% cycle retention during 100 cycles and an improvement of the volumetric energy density by over seven-fold.

• Metal–organic framework-based interfacial modifier for biphasic solid electrolytes. • The nanoporous metal–organic framework layer homogenizes the Li+ flux. • The interfacial modifier forms stable interfaces with intimate solid–solid contact. • The solid electrolyte with the interfacial modifier enables stable cycling. Solid-state lithium batteries (SSLBs) based on non-flammable inorganic solid electrolytes have been proposed as promising technical solutions to resolve safety issues caused by flammable organic liquid electrolytes of current Li-ion batteries. Biphasic solid electrolytes (BSEs) comprising Li+-conducting oxides and polymers have garnered significant interest for SSLBs because of their mechanical robustness and high Li+ conductivity. However, the non-uniform distribution of oxide particles and polymer species in BSEs may cause inhomogeneous Li+ conduction, thereby resulting in poor interfacial stability with electrodes during repeated charge–discharge cycles. Herein, we report a Li 7 La 3 Zr 2 O 12 -based BSE with homogeneous Li+ transport pathways achieved by a metal–organic framework (MOF) layer. To regulate and homogenize the Li+ flux across the interface between the BSE and electrode, a free-standing BSE is integrated with the MOF layer. The MOF-integrated BSE forms smooth and uniform interfaces with nanoporous channels in contact with the electrodes, effectively enhancing the interfacial solid–solid contact and facilitating homogeneous Li+ transport. An SSLB with the MOF-BSE membrane shows enhanced cycling stability and rate-capability compared to the battery with bare BSE. This study demonstrates that the proposed electrolyte design provides an effective approach for improving the conducting properties and interfacial stability of BSEs for high-performance and long-cycling SSLBs. [Display omitted] [ABSTRACT FROM AUTHOR]

Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO), a typical oxidizing ceramic solid electrolyte of excellent lithium-ion conductivity, is considered as a promising candidate for next-generation high-energy-density solid-state lithium metal batteries (SSLMBs). However, great challenges, such as the unexpected growth of lithium dendrites and the excessive resistance of electrolyte/electrode interface, need to be well addressed through their commercialization. Here, a local conjugated polymer solid-state electrolytes nanolayer was formed onto ceramic oxide particles via selective adsorption through an in-situ polymerization process. Li solid NMR spectra and TEM (ex-situ and in-situ) characterizations suggest that optimized layer provided effective pathways for Li+ conduction between SSEs and ceramic oxide. Consequently, this composite electrolyte possesses a high ionic conductivity of 0.69 mS cm−1 at 25 °C. Lithium symmetrical batteries exhibit a reduced charge voltage polarization and the critical current density could be increased up to 2.4 mA cm−2. Moreover, lithium metal batteries based on CPE show an excellent cycle stability over a broad temperature range from −20 to 70 °C, and super-long cycling performance (> 600 cycles) at 0.5 C under 0 °C. This new strategy creates a new route to resolve the LLZTO/electrode interface issue by constructing rich-large space charge layer and promoting Li+ conduction, it will be helpful for the commercialization and application of wide-temperatures SSLMBs. An asymmetric bilayer solid-stated electrolyte was synthesized via a simple selective adsorption and in-situ thermal polymerization process. Such a configuration can create a new route to resolve the LLZTO/electrode interface issue by constructing rich-large space charge layer and promote Li+ conduction. Assembled LiFePO 4 /Li battery could deliver excellent cycling performance at −20 – 70 ℃. [Display omitted] • Asymmetric bilayer SSEs were fabricated via an in-situ polymerization process. • Boosted ion transport was enabled by charge-rich space charge layer between SSEs and ceramic oxide. • Optimized asymmetric bilayer SSEs exhibit superior ionic conductivity and mechanical properties. • Solid state lithium metal batteries show excellent electrochemical performance over wide-temperature range. [ABSTRACT FROM AUTHOR]

To realize high-performance all-solid-state batteries, an efficient design for all-solid-state electrodes is vital. Composite electrode, which is comprised of well-mixed active material and solid electrolyte, is a typical structure to build well-percolated ionic pathways within the electrode. In contrast, diffusion-dependent electrode, which consists mostly of active material, is an emerging approach that utilizes interparticle diffusion between active material particles for charge/discharge. This design enables maximization of energy density and simplification of the fabrication process. Herein, we present a hybrid all-solid-state electrode that combines the merits of each electrode as a new electrode concept. This electrode consists of a bilayer structure of the composite electrode and the diffusion-dependent electrode, and its electrochemical features such as initial Coulombic efficiency, capacity retention, and energy density are systematically analyzed. Owing to the active utilization of lithium-ion transports via percolated solid electrolyte particles and interparticle diffusion of active material particles, the graphite-based hybrid electrode with a practically meaningful capacity (∼4 mA h cm−2) is demonstrated to deliver moderately high energy densities at various C-rates. In particular, silicon/graphite-based hybrid electrode can exhibit high normalized capacities of 5.83 mA h cm−2 and 1300 mA h cm−3, which are among the highest values reported to date for all-solid-state batteries. [Display omitted] • Hybrid electrode design is proposed as a high-performance all-solid-state electrode. • This electrode utilizes lithium-ion conduction and diffusion for charge/discharge. • The silicon/graphite-based hybrid electrode realizes excellent energy density. [ABSTRACT FROM AUTHOR]

To prevent global warming, ESS development is in progress along with the development of electric vehicles and renewable energy. However, the state-of-the-art technology, i.e., lithium-ion batteries, has reached its limitation, and thus the need for high-performance batteries with improved energy and power density is increasing. Lithium-sulfur batteries (LSBs) are attracting enormous attention because of their high theoretical energy density. However, there are technical barriers to its commercialization such as the formation of dendrites on the anode and the shuttle effect of the cathode. To resolve these issues, a boron nitride nanotube (BNNT)-based separator is developed. The BNNT is physically purified so that the purified BNNT (p−BNNT) has a homogeneous pore structure because of random stacking and partial charge on the surface due to the difference of electronegativity between B and N. Compared to the conventional polypropylene (PP) separator, the p−BNNT loaded PP separator prevents the dendrite formation on the Li metal anode, facilitates the ion transfer through the separator, and alleviates the shuttle effect at the cathode. With these effects, the p−BNNT loaded PP separators enable the LSB cells to achieve a specific capacity of 1429 mAh/g, and long-term stability over 200 cycles. [ABSTRACT FROM AUTHOR]

All-solid-state batteries (ASSBs) are gaining traction in the arena of energy storage due to their promising results in producing high energy density and long cycle life coupled with their capability of being safe. The key challenges facing ASSBs are low conductivity and slow charge transfer kinetics at the interface between the electrode and the solid electrolyte. Garnet solid-state electrolyte has shown promising results in improving the ion conductivity but still suffers from poor capacity retention and rate performance due to the interfacial resistance between the electrodes. To improve the interfacial resistance, we prepared a composite consisting of Li7La2.75Ca0.25Zr1.75Nb0.25O12 (LLCZN) garnet material as the ceramic, polyethylene oxide (PEO) as the polymer, and lithium hexafluorophosphate (LiPF6) as the salt. These compounds are mixed in a stoichiometric ratio and developed into a very thin disc-shaped solid electrolyte. The LLCZN provides a lithium-ion transport path to enhance the lithium-ion conduction during charging and discharging cycles, while the LiPF6 contributes more lithium ions via the transport path. The PEO matrix in the composite material aids in bonding the compounds together and creating a large contact area, thereby reducing the issue of large interfacial resistance. FESEM images show the porous nature of the electrolyte which promotes the movement of lithium ions through the electrolyte. The fabricated LLCZN/PEO/LiPF6 solid-state electrolyte shows outstanding electrochemical stability that remains at 130 mAh g−1 up to 150 charging and discharging cycles at 0.05 mA cm−2 current. All the specific capacities were calculated based on the mass of the cathode material (LiCoO2). In addition, the coin cell retains 85% discharge capacity up to 150 cycles with a Coulombic efficiency of approximately 98% and energy efficiency of 90% during the entire cycling process. [ABSTRACT FROM AUTHOR]

To prevent global warming, ESS development is in progress along with the development of electric vehicles and renewable energy. However, the state-of-the-art technology, i.e., lithium-ion batteries, has reached its limitation, and thus the need for high-performance batteries with improved energy and power density is increasing. Lithium-sulfur batteries (LSBs) are attracting enormous attention because of their high theoretical energy density. However, there are technical barriers to its commercialization such as the formation of dendrites on the anode and the shuttle effect of the cathode. To resolve these issues, a boron nitride nanotube (BNNT)-based separator is developed. The BNNT is physically purified so that the purified BNNT (p-BNNT) has a homogeneous pore structure because of random stacking and partial charge on the surface due to the difference of electronegativity between B and N. Compared to the conventional polypropylene (PP) separator, the p-BNNT loaded PP separator prevents the dendrite formation on the Li metal anode, facilitates the ion transfer through the separator, and alleviates the shuttle effect at the cathode. With these effects, the p-BNNT loaded PP separators enable the LSB cells to achieve a specific capacity of 1429 mAh/g, and long-term stability over 200 cycles.

The application of lithium (Li) metal anodes in Li metal batteries has been hindered by growth of Li dendrites, which lead to short cycling life. Here a Li‐ion‐affinity leaky film as a protection layer is reported to promote a dendrite‐free Li metal anode. The leaky film induces electrokinetic phenomena to enhance Li‐ion transport, leading to a reduced Li‐ion concentration polarization and homogeneous Li‐ion distribution. As a result, the dendrite‐free Li metal anode during Li plating/stripping is demonstrated even at an extremely high deposition capacity (6 mAh cm−2) and current density (40 mA cm−2) with improved Coulombic efficiencies. A full cell battery with the leaky‐film protected Li metal as the anode and high‐areal‐capacity LiNi0.8Co0.1Mn0.1O2 (NCM‐811) (≈4.2 mAh cm−2) or LiFePO4 (≈3.8 mAh cm−2) as the cathode shows improved cycling stability and capacity retention, even at lean electrolyte conditions. [ABSTRACT FROM AUTHOR]

With the increased need for high-rate Li-ion batteries, it has become apparent that new electrode materials with enhanced Li-ion transport should be designed. Interfaces, such as twin boundaries (TBs), offer new opportunities to navigate the ionic transport within nanoscale materials. Here, we demonstrate the effects of TBs on the Li-ion transport properties in single crystalline SnO2 nanowires. It is shown that the TB-assisted lithiation pathways are remarkably different from the previously reported lithiation behavior in SnO2 nanowires without TBs. Our in situ transmission electron microscopy study combined with direct atomic-scale imaging of the initial lithiation stage of the TB-SnO2 nanowires prove that the lithium ions prefer to intercalate in the vicinity of the (101̅) TB, which acts as conduit for lithium-ion diffusion inside the nanowires. The density functional theory modeling shows that it is energetically preferred for lithium ions to accumulate near the TB compared to perfect neighboring lattice area. These findings may lead to the design of new electrode materials that incorporate TBs as efficient lithium pathways, and eventually, the development of next generation rechargeable batteries that surpass the rate performance of the current commercial Li-ion batteries.