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Cathode interface instability is a significant obstacle for the practical application of sulfide-based all-solid-state lithium-ion batteries (ASSLIBs). However, the origin of cathode interface degradation is lack of comprehensive understanding. In this paper, X-ray characterizations combined with electrochemical analysis are adopted to investigate the underlying degradation mechanism at cathode interface. The results indicate that residual lithium compounds on the surface of Ni-rich LiNi0.8Mn0.1Co0.1O2 (NMC811) are the main reason that triggering the oxidation of sulfide solid-state electrolytes (SSEs), therefore inducing severe side-reactions at cathode interface and structural degradation of NMC811. The degradation of the cathode interface can be significantly suppressed when the cathode surface is cleaned. As a result, the surface cleaned NMC811 without coating demonstrates significantly improved electrochemical performance in both Li5.5PS4.5Cl1.5 (LPSCl) and Li10GeP2S12 (LGPS) based ASSLIBs, proving the universal application of this strategy.

The development of high-performance sulfide electrolyte-based all-solid-state lithium-ion batteries (ASSLIBs) has been inhibited by problematic ionic transport and side reactions at the cathode interface, and their success is dependent on the functionalized interface upon charging and discharging. Despite recent progresses, it has proven challenging to design a favorable interface that can suppress the side reactions and enable smooth motion of Li+ ions. Herein, a favorable Zr-based cathode interface is elaborately manipulated by the atomic layer deposition (ALD) for sulfide-based ASSLIBs. Flexile control over the Li sub-cycle during the preparation process is demonstrated to be crucial for achieving a robust cathode interface with a desirable Li+ ionic conductivity. The ASSLIBs equipped with this functional interface exhibit excellent cycling stability and rate capability at room temperature (RT). Various electrochemical and spectroscopic characterizations reveal that the ionic conductive interface can significantly limit side reactions and induce a low polarization of the (de)intercalation toward cathode materials. The interfacial manipulation regarding ionic conductivity and structure realized by ALD provides a new strategy to achieve high-performance ASSLIBs.

Li–O2 battery is a promising rechargeable battery candidate due to its ultrahigh theoretical energy density. However, safety issues and poor cycling stability of Li–O2 batteries caused by the forma...

The separator is used to isolate the cathode and anode material, playing an important role in the safety of battery, which prevents internal short circuit of battery and provides lithium ions free flow channels. In this paper, based on the commercial ceramic-coated polyethylene (PE) separator (CPES), low-melting point PE microspheres were mixed in ceramic-coating to form the functionalized PE separator (FPES) for improving the safety tolerance of large scale lithium-ion batteries (LIBs). Compared to the CPES shutdown temperature of ~135 °C, the shutdown temperature of FPES significantly decreased to ~110 °C. Compared with 27 Ah pouch battery assembled by CPES, the FPES can effectively improve the tolerance of overcharge and internal short circuit without sacrificing the electrochemical performance. In addition, a novel internal short circuit of FPES protection mechanism model was proposed. Molten PE microspheres of FPES would flow along the edge of broken hole, reducing the contact probability between the cathode and anode, and ultimately increasing the resistance of internal short circuit by 41% compared to CPES. Therefore, the obtained results provide important implications for the development of safer separator and LIBs.

All-solid-state lithium-ion batteries (ASSLIBs) are receiving significant attention owing to their improved safety and energy density over liquid counterparts. However, single-crystal cathodes have never been investigated in ASSLIBs. In this work, single-crystal Li(Ni0·5Mn0·3Co0.2)O2 (SC-NMC532) is used as the cathode material for ASSLIBs, which exhibits 6–14 times higher Li+ diffusion coefficient than polycrystalline Li(Ni0·5Mn0·3Co0.2)O2 (PC-NMC532). As a result, SC-NMC532 exhibits an initial specific capacity of 156.4 ​mAh.g−1 while PC-NMC532 shows an initial capacity of only 127.5 ​mAh.g−1. After 150 cycles, SC-NMC532 retains the capacity of 94.5 ​mAh.g−1. More impressively, under a high current density of 1.3 ​mA ​cm−2, SC-NMC532 exhibits a capacity of 82 ​mAh.g−1, much higher than that of PC-NMC532 (2.1 ​mAh.g−1). This work demonstrates that single-crystal NMC cathodes could enable both high power density and high energy density of ASSLIBs.

One of the primary obstacles that has inhibited the development of solid-state batteries is the lower conductivity of solid electrolytes compared to liquid electrolytes. Li6PS5Br is a promising solid electrolyte for solid-state batteries due to its high ionic conductivity and low cost. Herein, we enhance the lithium conductivity by replacing S with Br and systematically tailor the composition and synthesis parameters to optimize the conductivity. Li5.5PS4.5Br1.5 exhibits higher ionic conductivity and better lithium compatibility than the bare Li6PS5Br. Although lithium metal is chemically unstable with Li5.5PS4.5Br1.5, stable cycling behavior in lithium symmetrical cells with small overpotential and resistance after 2500 ​h are achieved. Both the bare NCM622 and LiNbO3-coated NCM622 shows long cycling life with Li5.5PS4.5Br1.5 electrolyte in combination with In or lithium metal anodes. The LiNbO3 layer can effectively improve the capacity and cycling behavior of the solid-state battery using different anodes. Moreover, the electrochemical performances of Li5.5PS4.5Br1.5-based solid-state batteries are influenced by the charge/discharge voltage windows.

Recently, halide solid-state electrolytes (SSEs) have been reported to exhibit high ionic conductivity and good compatibility with cathode materials. However, the air stability of halide-based elec...

Li–O2 batteries have attracted significant interest in the past decade owing to their superior high specific energy density in contrast to conventional lithium ion batteries. An 8.7-Ah Li–O2 pouch cell with 768.5 Wh kg−1 was fabricated and characterized in this investigation and the factors that influenced the electrochemical performance of the Li–O2 pouch cell were studied. In contrast to coin/Swagelok-type Li–O2 cells, it was demonstrated that the high-loading air electrode, pulverization of the Li anode, and the large-scale inhomogeneity of the large pouch cell are the major reasons for the failure of Li–O2 batteries with Ah capacities. In addition, safety tests of large Li–O2 pouch cells were conducted for the first time, including nail penetration, crushing, and thermal stability. It was indicated that a self-limiting mechanism is a key safety feature of these batteries, even when shorted. In this study, Li–O2 batteries were investigated in a new size and capacity-scale, which may provide useful insight into the development of practical pouch-type Li–O2 batteries.

All-solid-state lithium sulfur batteries (ASSLSBs) are considered promising candidates for next-generation energy-storage systems due to their enhanced safety and high theoretical energy density. However, usually both solid-state electrolyte (SSE) and conductive carbon need to be incorporated into the cathode composite to provide Li+/electron pathways, leading to the reduced energy density and inevitable SSE decomposition. Moreover, the real electrochemical behavior of S or Li2S cathodes can not be reflected due to the partially overlapped redox reaction of SSE. Herein, a series of unique P4S10+n cathodes for high-performance ASSLSBs that totally do not need any extra SSE additives are reported. Synchrotron-based X-ray absorption near edge structure coupled with other analyses confirmed that ionic conductive Li3PS4 together with Li4P2S6 components can be electrochemically self-generated during lithiation process and partially maintained to provide fast Li+ transport pathways within the cathode layer. This is further evidenced by a 30–43-fold higher reversible capacity for P4S10+n/C cathodes compared to a S/C cathode. Bulk-type ASSLSBs based on the P4S34/C cathode show a highly reversible capacity of 883 ​mAh g−1 and stable cycling performance over 180 cycles with a high active material content of 70 ​wt%. The present study provides a promising approach for generating ionic conductive components from the electrode itself to facilitate Li+ migration within electrodes in ASSLSBs.

All-solid-state lithium-ion batteries (ASSLIBs) are expected as safe and high-performance alternatives to replace the conventional liquid-based lithium-ion batteries. However, the incompatible interface between the most cathode materials and sulfide-based solid electrolytes is still challenging the stable delivery of electrochemical performance for ASSLIBs. Herein, a dual-functional Li3PO4 (LPO) modification is designed for Ni-rich layered oxide cathodes in sulfide-based ASSLIBs to realize the high performance. The modified cathode demonstrates a significantly improved initial capacity of 170.6 ​mAh g-1 at 0.1C, better rate capability, and reduced polarization compared to the bare cathode. More importantly, a stable long-term cycling is achieved with a low capacity degradation rate of 0.22 ​mAh g-1 per cycle for 300 cycles at 0.2C. The detailed surface chemical and structural evolutions are studied via X-ray absorption near edge spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The results indicate that the LPO modification not only significantly suppresses the side-reactions with sulfide electrolyte but also helps to alleviate the deterioration of the microstructural cracks during the electrochemical reactions. This work provides an ideal and controllable interfacial design for realizing high performance sulfide-based ASSLIBs, which is readily applicable to other solid-state battery systems.

Solid polymer electrolytes (SPEs)-based all-solid-state lithium batteries (ASSLBs) with high-safety and high-performance have been regarded as promising next-generation energy storage devices. A fly in the ointment is that the cycling life is significantly limited by the Li dendrite growth. To tackle the Li dendrite issue, a selective Li deposition strategy is proposed, for the first time, to suppress Li dendrite formation via the rational design of a patterned Li anode. Through a facile and low-cost template-press method, the Li anode was divided into numerous square Li with deep grooves around 100 ​μm. Benefiting from the focused current density in the grooves, the Li preferentially deposits in the grooves instead of on the surface, thus suppressing the Li dendrite formation during the Li plating/stripping process. With this in mind, both cycling life of the assembled Li–Li symmetric cells and Li–LiFePO4 (LFP) full cells is prolonged for over 5 times. The Li–Li symmetric cells assembled with the patterned Li exhibit excellent cycling stability for 800/400 ​h ​at 0.1/0.2 ​mA ​cm−2. More importantly, the 3–4 ​mg ​cm−2 LFP-loaded patterned Li/PEO/LFP cell achieves high capacity retention of 91.3% within 100 cycles at 0.5C, while different degrees of short-circuits occurred for the bare Li/PEO/LFP cells.

The enabling of high energy density of all-solid-state lithium batteries (ASSLBs) requires the development of highly Li+-conductive solid-state electrolytes (SSEs) with good chemical and electrochemical stability. Recently, halide SSEs based on different material design principles have opened new opportunities for ASSLBs. Here, we discovered a series of LixScCl3+x SSEs (x = 2.5, 3, 3.5, and 4) based on the cubic close-packed anion sublattice with room-temperature ionic conductivities up to 3 × 10-3 S cm-1. Owing to the low eutectic temperature between LiCl and ScCl3, LixScCl3+x SSEs can be synthesized by a simple co-melting strategy. Preferred orientation is observed for all the samples. The influence of the value of x in LixScCl3+x on the structure and Li+ diffusivity were systematically explored. With increasing x value, higher Li+, lower vacancy concentration, and less blocking effects from Sc ions are achieved, enabling the ability to tune the Li+ migration. The electrochemical performance shows that Li3ScCl6 possesses a wide electrochemical window of 0.9-4.3 V vs Li+/Li, stable electrochemical plating/stripping of Li for over 2500 h, as well as good compatibility with LiCoO2. LiCoO2/Li3ScCl6/In ASSLB exhibits a reversible capacity of 104.5 mAh g-1 with good cycle life retention for 160 cycles. The observed changes in the ionic conductivity and tuning of the site occupations provide an additional approach toward the design of better SSEs.

Sulfide-based solid-state electrolytes (SSEs) are considered a key part in the realization of high-performance all solid-state lithium-ion batteries (ASSLIBs). However, the incompatibility between ...

All-solid-state Li metal batteries (ASSLMBs) have attracted significant attention because of their high energy density and improved safety. However, the poor stability at the Li anode/solid-state e...

Sulfide solid electrolytes have recently attracted significant interest for use in all-solid-state lithium batteries (ASSLBs) due to their high ionic conductivity. However, one of the main challeng...

All-solid-state lithium batteries (ASSLBs) are promising energy storage devices for application in electric transportation and large-scale energy storage systems. Polyethylene oxide (PEO)-based solid polymer electrolytes (SPEs) are attractive solid-state electrolytes for ASSLBs due to their high ionic conductivity, light weight, and low cost. However, the low electrochemical oxidation potential window of PEO seriously restricts its implementation with high voltage cathodes for high-energy-density ASSLBs. Effective interfacial engineering between high voltage cathodes and SPEs can be a solution. Most of the reported conventional cathode protection approaches have been focused on building coating layers on active material particles, which, however, can be insufficient because the conductive carbon is able to accelerate the decomposition of SPEs. In this work, atomic layer deposition (ALD) coating on the electrode instead of active material particles realizes a unique method to protect the cathode/SPE interface. As a successful example, a thin ALD-derived lithium tantalate coating on the high-voltage LiCoO2 electrode demonstrated good compatibility with PEO-based SPEs, significantly enhancing the cycling performance of the ASSLBs. The inner mechanism is attributed to the fact that the protection of the conductive carbon/SPE interface helps reduce the electrochemical oxidation of PEO-based SPEs. This work shall give new insights for the interfacial engineering of high voltage cathodes and solid polymer electrolytes.

Due to higher energy density, high-voltage all-solid-state lithium batteries (ASSLBs) have attracted increasing attention. However, they require solid-state electrolytes (SSEs) with wide electrochemical stability windows (ESW, typically >4.2 V) and high-stability against the Li anode. Nevertheless, poly(ethylene oxide) (PEO), the most widely used solid polymer electrolyte (SPE), can’t tolerate a high-voltage over 4 V. Whether the main chain (–C–O–C–) or the terminal hydroxide group (–OH) is the limiting factor for the narrow ESW remains unknown. Herein, poly(ethylene glycol) (PEG) and poly(ethylene glycol)dimethyl ether (PEGDME) with different terminal groups are selected to answer this question. The results show that the reactive terminal –OH group is the limiting factor towards applicability against high voltage and the Li anode. Replacing –OH with more stable –OCH3 can significantly extend the ESW from 4.05 to 4.3 V, while improving the Li-anode compatibility as well (Li–Li symmetric cells stably run for 2500 h at 0.2 mA cm−2). Its practical application is further proved by developing PEGDME-based ASSLB pouch cells. The 0.53 mA cm−2 Li–LiFePO4 and 0.47 mA h cm−2 Li–LiNi0.5Mn0.3Co0.2O2 cells demonstrated high capacity retention of 97% and 90% after 210 cycles and 110 cycles, respectively. This work offers a new strategy for PEO-based high-voltage ASSLB development by changing the unstable terminal groups.

Silicon nanowires of high purity and regular morphology are of prime importance to ensure high specific capacities of lithium-ion batteries and reproducible electrode assembly process. Using nickel formate as a metal catalyst precursor, straight silicon nanowires (65–150 nm in diameter) were directly prepared by electrolysis from the Ni/SiO2 porous pellets with 0.8 wt% nickel content in molten CaCl2 at 900 °C. Benefiting from their straight appearance and high purity, the silicon nanowires therefore offered an initial coulombic efficiency of 90.53% and specific capacity of 3377 mAh/g. In addition, the silicon nanowire/carbon composite exhibited excellent cycle performance, retaining 90.38% of the initial capacity after 100 cycles. Whilst further study on the charge storage performance is still ongoing, these preliminary results demonstrate that nickel formate is an efficient and effective metal catalyst precursor for catalytic preparation of high purity straight silicon nanowires via the molten salt electrolysis, which is suitable for large-scale production.

All-solid-state batteries are expected to be promising next-generation energy storage systems with increased energy density compared to the state-of-the-art Li-ion batteries. Nonetheless, the electrochemical performances of the all-solid-state batteries are currently limited by the high interfacial resistance between active electrode materials and solid-state electrolytes. In particular, elemental interdiffusion and the formation of interlayers with low ionic conductivity are known to restrict the battery performance. Herein, we apply a nondestructive variable-energy hard X-ray photoemission spectroscopy to detect the elemental chemical states at the interface between the cathode and the solid-state electrolyte, in comparison to the widely used angle-resolved (variable-angle) X-ray photoemission spectroscopy/X-ray absorption spectroscopy methods. The accuracy of variable-energy hard X-ray photoemission spectroscopy is also verified with a focused ion beam and high-resolution transmission electron microscopy. We also show the significant suppression of interdiffusion by building an artificial layer via atomic layer deposition at this interface.

Poly(ethylene oxide) (PEO) based solid polymer electrolytes (SPEs) have been regarded as promising electrolytes for next-generation all-solid-state lithium batteries (ASSLBs). However, they have achieved limited cycling stability due to their inability to suppress Li dendrite growth. Herein, a self-healing electrostatic shield (SHES) is proposed to force uniform lithium deposition by introducing 0.05 M Cs+. At this situation, the Cs+ shows a lower reduction potential compared to the Li+ reduction potential (1.7 M). During lithium deposition, the Cs+ forms a positively charged electrostatic shield around the initial Li tips, which forces further deposition of lithium to adjacent regions of the anode and results in a dendrite-free Li deposition. With this in mind, the Li–Li symmetric cells can operate for 1000 and 500 h at current densities of 0.1 and 0.2 mA cm−2, respectively, which are 10 times longer than Cs+-free PEO electrolyte. Moreover, the Li/PEO-Cs+/LiFePO4 (LFP) cell achieves high capacity retention of 90% within 100 cycles at 0.5C and retains a high capacity of 113 mAh g−1 at 0.8C, while short-circuits are observed for the Li/PEO/LFP cell, even at 0.2C. This strategy will generate substantial interest and shed light on the development of other dendrite-free SPEs and ASSLBs systems.

All-solid-state lithium-ion batteries (SSLIBs) are promising candidates to meet the requirement of electric vehicles due to the intrinsic safety characteristics and high theoretical energy density....

All-solid-state lithium batteries (ASSLBs) assembled with solid polymer electrolytes (SPEs) have been regarded as promising next-generation rechargeable batteries with improved safety and high energy densities. However, the Li dendrites and poor Li+ transport greatly inhibit their practical applications when coupled with relatively high loading cathodes. Herein, we combine a glass fiber (GF)-reinforced composite polymer electrolyte based on poly(ethylene oxide) (labeled as PEO@GF) to suppress Li dendrite growth with a freeze-casted vertically-aligned (VL) electrode to facilitate Li+ transport in the high loading cathode. Benefiting from the enhanced mechanical strength and uniformed Li deposition enabled by the implanted GF, the Li–Li symmetric cells exhibit significantly improved cycling stability up to 2000 h (0.2 mA cm−2, 0.2 mAh cm-2) and 1000 h (0.42 mA cm−2, 0.4 mAh cm−2), which are over one order of magnitude longer than those of the pure PEO electrolyte. Furthermore, VL-LiFePO4 (LFP) cathode divides the thick electrode into numerous vertically-aligned “thin electrodes”, which significantly decreases the Li+ transport distance and enables the Li | PEO@GF | VL-LFP cell with a high LFP loading of 10.5 mg cm-2 to deliver a high areal capacity of 1.52 mAh cm−2. The rational structure design of both electrolyte and electrode offers an opportunity for developing high-performance ASSLBs with high active material loadings.

Li- and Mn-rich (LMR) layered materials with large specific capacities are one of the most promising cathodes for high-energy Li-ion batteries. However, the oxygen redox reaction induced by the activation of the Li2MnO3 component leads to lattice oxygen release and transition metal migration from the surface, which result in a large irreversible capacity loss, poor rate capability and inferior cycle stability compared with other cathodes. In this study, an integrated surface modification of combining a coating and chemical treatment is proposed to achieve modified LMR cathode materials with graphene wrapping layers and surface spinel phases. The graphene layer promotes electron transfer, and the spinel phase interlayer accelerates Li+ diffusion. Simultaneously, the combination of the two components increases the structural stability of LMR materials. As a result, the surface-modified LMR cathode exhibits a high rate capability of 154.3 mA h g−1 at 5C and an excellent cycle stability with a capacity retention of 84.2% after 200 cycles at 1C. In addition, the structural evolution of the surface-modified LMR cathode material was studied by in situ synchrotron X-ray diffraction analysis during the charge–discharge process, which illustrates that the surface modification has a significant effect on mitigating oxygen release by enhancing the surface structural stability.

Most inorganic solid-state electrolytes (SSEs) suffer from incompatibility with oxide cathode materials and instability in ambient air, presenting major barriers for their application in high performance all-solid-state batteries (ASSLBs). Herein, we report a rationally designed halide-based Li3InCl6 SSE with a high ionic conductivity of 1.49 × 10−3 S cm−1 (25 °C). The Li3InCl6 SSE is stable towards oxide cathode materials (e.g., LiCoO2) without any interfacial treatment. By applying the Li3InCl6 SSEs, significantly enhanced electrochemical performances are achieved in terms of capacity and durability. Experimental investigations reveal that the Li3InCl6 can avoid side reactions between the SSEs and the oxide cathode materials and thus effectively improve the Li+ migration across the interface. Moreover, Li3InCl6 is highly stable in ambient air and possesses good ionic conductivity retention after a reheating process, further making it an attractive electrolyte for next-generation ASSLBs.

The Li metal anode is an ideal candidate for next-generation batteries due to its ultra-high specific capacity (3860 mAh g−1) and low electrochemical potential (−3.040 V vs. standard hydrogen electrode). However, the large volume fluctuations, side reactions, and dendrite growth are serious problems that need to be solved before Li metal batteries (LMBs) can be commercialized. Herein, we develop a lithiophilic 3D Cu nanowire (3D CuNW) host that can enable molten Li infusion into the structure. Interestingly, the 3D host undergoes a structural transformation upon contact with molten Li and forms Cu-Li alloy crystallites on the surface, leading to the development of an ultra-high performance Li metal anode (3D Li@CuLi). The symmetrical cell performance of the 3D Li@CuLi electrode is found to be among the best reported for carbonate-based electrolytes and can achieve greater than 200 cycles at an ultra-high current density of 10 mA cm−2. Furthermore, full cells coupled with LiFePO4 cathodes show excellent cycling stability at a C-rate of 2 C for over 400 cycles with negligible capacity fade. This work provides a scalable and highly effective approach towards the fabrication of high performance 3D hosts with pre-stored Li metal for next-generation battery systems.

Safe and high-energy-density lithium rechargeable batteries are urgently required for vehicle electrification and grid energy storage. All-solid-state lithium metal batteries (ASSLMBs) are regarded as a good choice to meet these stringent requirements. However, interfacial instability between Li metal and solid-state sulfide electrolytes (SEs) and lithium dendrite formation are main challenges to be overcome. In this work, molecular layer deposition (MLD) is employed for the first time to develop an inorganic-organic hybrid interlayer (alucone) at the interface between the Li metal and SEs. It is found that the alucone layer can serve as an artificial solid electrolyte interphase (SEI). As a result, interfacial reactions between Li and SEs are significantly suppressed by intrinsically blocking electron transfer at the interface. In addition, lithium dendrites are also suppressed. Coupled with a LiCoO2 cathode, ASSLMBs with 30 MLD cycles of alucone on Li metal exhibit a high initial capacity of 120 mAh g−1 and can retain a capacity of 60 mAh g−1 after 150 cycles. This work exemplifies the use of MLD to stabilize the interface between SEs and Li metal for ASSLMBs.

The development of all-solid-state Li metal batteries (ASSLMBs) has attracted significant attention due to their potential to maximize energy density and improved safety compared to the conventional liquid-electrolyte-based Li-ion batteries. However, it is very challenging to fabricate an ideal solid-state electrolyte (SSE) that simultaneously possesses high ionic conductivity, excellent air-stability, and good Li metal compatibility. Herein, a new glass-ceramic Li3.2 P0.8 Sn0.2 S4 (gc-Li3.2 P0.8 Sn0.2 S4 ) SSE is synthesized to satisfy the aforementioned requirements, enabling high-performance ASSLMBs at room temperature (RT). Compared with the conventional Li3 PS4 glass-ceramics, the present gc-Li3.2 P0.8 Sn0.2 S4 SSE with 12% amorphous content has an enlarged unit cell and a high Li+ ion concentration, which leads to 6.2-times higher ionic conductivity (1.21 × 10-3 S cm-1 at RT) after a simple cold sintering process. The (P/Sn)S4 tetrahedron inside the gc-Li3.2 P0.8 Sn0.2 S4 SSE is verified to show a strong resistance toward reaction with H2 O in 5%-humidity air, demonstrating excellent air-stability. Moreover, the gc-Li3.2 P0.8 Sn0.2 S4 SSE triggers the formation of Li-Sn alloys at the Li/SSE interface, serving as an essential component to stabilize the interface and deliver good electrochemical performance in both symmetric and full cells. The discovery of this gc-Li3.2 P0.8 Sn0.2 S4 superionic conductor enriches the choice of advanced SSEs and accelerates the commercialization of ASSLMBs.

Electrolyte is the key to constructing the ionic transport paths and O2 gas diffusion routes in the cathode as well as maintaining the electrode interfacial stability in view of the complex chemistry of Li–O2 batteries. A novel poly(vinyl formal) (PVFM)-based Janus membrane, which is prepared via coating multiwalled carbon nanotubes (MWCNTs) on the porous side of the cross-linked PVFM membrane, has been proposed herein to achieve membrane-supporting gel polymer electrolyte (GPE) for Li–O2 batteries. Within Li–O2 batteries, the dense side of PVFM-based Janus membrane demonstrates a good compatibility with lithium metal anode, while the other side with MWCNTs coating reserves much more solvent on the surface, assisting the cathode to form enlarged electrolyte-wetted interface. Moreover, the comparative studies indicate that PVFM-based Janus membrane also can provide a conductive pathway, modulate the morphology of the discharge products, and produce accommodation space for the products. So, the Li–O2 batter...

Lithium-rich layered oxides are promising cathode materials for high-energy-density lithium-ion batteries. However, the development of cathode materials based on these layered oxides has been limited by voltage fading, poor rate performance, and the low tap density of these materials. In this work, we prepared a material consisting of micrometer-scale spherical lithium-rich layered oxide particles with a three-dimensional conductivity network design and modified the surface of the primary particles with ruthenium. The as-obtained product with a maximum tap density of 2.1 g cm–3 shows a superior high reversible capacity with 280 mA h·g–1 at 0.1 C, a capacity retention of 98.1% after 100 cycles, and an outstanding rate capability. More importantly, enrichment of the primary particle surface with ruthenium can effectively suppress voltage decay. This cathode is feasible to construct high-energy and high-power lithium-ion batteries. This novel design may furthermore open the door to new material engineering a...

Solid-state lithium batteries have attracted significant attention recently due to their superior safety and energy density. Nevertheless, the large interfacial resistance has limited the development of SSLBs. To tackle this problem, a general strategy is to add liquid electrolytes (LE) at the interface to form a solid-liquid hybrid electrolyte. However, the effects and interfacial properties of LE in the solid-liquid hybrid electrolyte have not been well-understood. In this work, we quantitatively add LE at the interface to eliminate the large interfacial resistance and study its interfacial properties. As little as 2 µL of LE at the interface enables a hybrid LiFePO4/LATP/Li battery to deliver a specific capacity of 125 mA h g−1 at 1 C and 98 mA h g−1 at 4 C. Excess LE has no further contribution to the electrochemical performance. Furthermore, the rigid SSE could suppress the formation of lithium dendrites, especially in the case with a high cathode loading (9.1 mg/cm2), suggesting the feasibility of high energy density SSLBs using Li metal anodes. The interfacial analysis reveals that an interfacial solid-liquid electrolyte interphase (SLEI) was formed at the interface, preventing the reduction of LATP by Li metal, thus ensuring the long-term durability of LATP in LE.

LiNi0.6Co0.2Mn0.2O2 (NCM) is a highly potential cathode material for lithium-ion batteries (LIBs). However, its poor rate capability and cycling performance at high cutoff voltages have seriously hindered further commercialization. In this study, we successfully design an ultra-thin lithium aluminum oxide (LiAlO2) coating on NCM for LIBs. Compared to Al2O3, the utilization of lithium-ion conducting LiAlO2 significantly improves the NCM performance at high cutoff voltages of 4.5/4.7 V. The study reveals that the LiAlO2-coated NCM can maintain a reversible capacity of more than 149 mA h g−1 after 350 cycles with 0.078% decay per cycle. Furthermore, LiAlO2-coated NCM exhibits higher rate capacities [206.8 mA h g−1 at 0.2 C (50 mA g−1) and 142 mA h g−1 at 3 C] than the Al2O3-coated NCM (196.9 mA h g−1 at 0.2 C and 131.9 mA h g−1 at 3 C). Our study demonstrates that the ultra-thin LiAlO2 coating is superior to Al2O3 and significantly improves the capacity retention and rate capability of NCM for LIBs.

All-solid-state lithium–sulfur batteries (ASSLSBs) are promising candidates as the power source for future electric vehicles due to their high energy density and superior safety properties. However, one of the major challenges of state-of-the-art ASSLSBs is related to the high interfacial resistance resulting from the instability between the solid-state electrolyte (SSE) and electrodes and/or the side reactions between polysulfides and SSE. Herein, we propose and demonstrate the significant enhancement of the cycling stability of an ASSLSB through atomic layer deposition interfacial engineering on the polymer/oxide ceramic/polymer sandwich-structured SSE. The results show that as few as 10 cycles of ALD Al2O3 on the LATP can endow ASSLSBs with a discharge capacity of 823 mA h g−1 after 100 charge/discharge cycles, which is almost two times higher than that of the ASSLSB without an ALD coating and that of a Li–S battery with a liquid-based electrolyte. Such improvement is attributed not only to the blocking of the polysulfide shuttling effect via the use of a sandwich SSE but also the significant reduction of the side reaction between the polysulfide and oxide ceramic SSE, which introduces high interfacial resistance and degrades the electrochemical performance. The protection role and mechanism of the ALD layer is also confirmed and revealed by XRD, SEM and XPS measurements.

Li-rich and Mn-based oxides (LRMO) have been an obvious choice of high specific energy batteries owing to their unique anion redox behavior based on the main component Li2MnO3. However, there are still electrochemical behaviors that cannot perfectly match the theoretical structure. So far, most theoretical research on LRMO has been carried out around the ideal Li2MnO3 structure. Nevertheless, there are a great number of non-ideal local configurations in the pristine materials under the case of practical situations. Herein, the ubiquitous complex local structures (defect-like) in the interior of Li2MnO3 particle, some of which have not been observed in the past, are directly presented through the atomic-level observation. We summarized these structures and proposed for the first time the great influence of these local structures on the electrochemical and the oxygen redox behavior of LRMO by combining observation, DFT calculation, XAS, XPS and electrochemical experiments. These micro-structures have been roughly divided into four categories by the advanced AC-STEM, including the so-called stacking faults caused by the slip of the adjacent TM layer, the local multi-Li or multi-Mn arrangement due to the combination of different stacking type along a–b plane, the expansion of the interlayer spacing, and even the distribution of polycrystalline domains, of which the second and third configurations were observed for the first time. These types of local structures dominate the electrochemical reaction of electrodes in some aspects by improving the activity of oxygen non-bonding 2p states, along with the improvement of (de)intercalation ability for Li ions in the bulk through reducing the energy barrier, and they are even one of the sources of voltage hysteresis by affecting the energy level distribution of oxygen unoccupied 2p states after delithiation. This research has perfected a more comprehensive and practical understanding of LRMO under the case of practical situations, laying a key foundation for the further modification and application of LRMO cathode materials.

Lithium-manganese-rich transition metal oxides have attracted substantial R&D attention due to their potential for high energy-density lithium-ion batteries. In this work, in situ high-energy X-ray diffraction was deployed to investigate the phase evolution during the solid-state synthesis of Li[Li0.2Mn0.54Ni0.13Co0.13]O2. A step-wise consumption of the starting materials was observed during the one-step heating process primarily due to the heterogeneous nature of the precursor. According to observations from in situ high-energy X-ray diffraction, a two-step process was adopted to minimize the elemental heterogeneity of the final product. The electrochemical characterization results showed a substantial improvement on the reversible specific capacity for the material synthesized through the two-step process.

With the significant obstacles that have been conquered in lithium-sulfur (Li-S) batteries, it is urgent to impel accelerating development of room-temperature Li-S batteries with high energy density and long-term stability. In view of the unique solid-liquid-solid conversion processes of Li-S batteries, however, designing effective strategies to address the insulativity and volume effect of cathode, shuttle of soluble polysulfides, and/or safety hazard of Li metal anode has been challenging. An atomic layer deposition (ALD) is a representative thin film technology with exceptional capabilities in developing atomic-precisely conformal films. It has been demonstrated to be a promise strategy of solving emerging issues in advanced electrical energy storage (EES) devices via the surface modification and/or the fabrication of complex nanostructured materials. In this review, the recent developments and significances on how ALD improves the performance of Li-S batteries were discussed in detail. Significant attention mainly focused on the various strategies with the use of ALD to refine the electrochemical interfaces and cell configurations. Furthermore, the novel opportunities and perspective associated with ALD for future research directions were summarized. This review may boost the development and application of advanced Li-S batteries using ALD.

To promote the development of solid-state batteries, polymer-, oxide-, and sulfide-based solid-state electrolytes (SSEs) have been extensively investigated. However, the disadvantages of these SSEs, such as high-temperature sintering of oxides, air instability of sulfides, and narrow electrochemical windows of polymers electrolytes, significantly hinder their practical application. Therefore, developing SSEs that have a high ionic conductivity (>10-3 S cm-1 ), good air stability, wide electrochemical window, excellent electrode interface stability, low-cost mass production is required. Herein we report a halide Li+ superionic conductor, Li3 InCl6 , that can be synthesized in water. Most importantly, the as-synthesized Li3 InCl6 shows a high ionic conductivity of 2.04×10-3 S cm-1 at 25 °C. Furthermore, the ionic conductivity can be recovered after dissolution in water. Combined with a LiNi0.8 Co0.1 Mn0.1 O2 cathode, the solid-state Li battery shows good cycling stability.

Li1.3Al0.3Ti1.7(PO4)3 (LATP) is a popular solid electrolyte used in solid-state lithium batteries due to its high ionic conductivity. Traditionally, the densification of LATP is achieved by a high-temperature sintering process (about 1000 °C). Herein, we report the compaction of LATP by a newly developed cold sintering process and post-annealing. LATP pellets are first densified at 120 °C and then annealed at 650 °C, yielding an ionic conductivity of 8.04 × 10-5 S cm-1 at room temperature and a relative density of 93% with a low activation energy of 0.37 eV. High-resolution transmission electron microscopy of the cold sintered pellets is investigated as well, showing that the particles are interconnected with some nanoprecipitates at the grain boundaries. Such nanocrystalline-enriched grain boundaries are beneficial for lithium-ion transportation, which leads to higher ionic conductivity of the cold sintered sample. This new sintering process can direct new horizons for development of all solid-state batteries due to its simplicity.

Solid-state lithium batteries (SSLBs) are the promising next-generation energy storage systems because of their attractive advantages in terms of energy density and safety. However, the interfacial engineering and battery building are of huge challenges, especially for stiff oxide-based electrolytes. Herein, we construct SSLBs by a cosintering method using Li

The pursuit of high energy density and safe lithium ion batteries (LIBs) is a urgent goal for the development of next-generation electric vehicles (EVs). All-solid-state batteries (ASSBs) with the combination of poly(ethylene oxide) (PEO)-based solid polymer electrolyte (SPE) and Ni-rich lithium nickel manganese cobalt oxide LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode are promising candidates for EVs due to their improved energy density and safety. However, the low electrochemical oxidation window of PEO-based SPE and the instability of NMC811 at the charge/discharge process seriously restrict the battery performance. Herein, a high voltage stable solid-state electrolyte layer lithium niobium oxide (LNO) is coated on the NMC811 electrode surface by atomic layer deposition for stabilizing NMC811-PEO solid polymer batteries. Electrochemical tests show that LNO coating can stabilize the NMC811 active materials and mitigate the decomposition of SPE upon the cycling process, rendering a good performance of NMC811-PEO solid polymer battery. Mechanism studies by SEM, STEM, XAS, and XPS disclose that the uncoated NMC811 suffers from chemomechanical degradations along with oxygen release triggering the decomposition of SPE, which results in unstable cathodic electrolyte interphase. With LNO coating, chemomechanical degradations and oxygen release are inhibited and the decomposition of SPE is mitigated. This work renders a stable and high-performance high-energy-density SSB for high voltage application, which paves the way toward next-generation solid-state LIBs.

Lithium halide electrolytes with high ion conductivity and good cathode compatibility have shown great potential for solid-state batteries. Li3YBr6, with a conductivity of 0.39 mS/cm at room temperature, synthesized by mechanical milling (BM-Li3YBr6), which can be further increased by heat treatment. The annealing parameters are tailored to obtain pure Li3YBr6 (AN-Li3YBr6) with a higher conductivity of 3.31 mS/cm by annealing the BM-Li3YBr6 at 500 °C for 5 h. The higher conductivity of AN-Li3YBr6 compared to the previously-reported results is due to the lower activation energy. NMR and simulation results show that the lithium ion migration between Li-1 and Li-2 sites along the [001] direction is the major obstacle for lithium diffusion in AN-Li3YBr6. The K- and L3-edge X-ray absorption near-edge structure (XANES) of Y for BM-Li3YBr6 and AN-Li3YBr6 showed that Y exists with similar local structures. The increased vibrations of AN-Li3YBr6 due to increased temperatures increase the rate of lithium jumping from one site to another, yielding higher lithium ion mobility. Lithium nuclear density maps prove that the mobile lithium on the 4g(Li) site is more sensitive to the varying temperatures. Both BM- and AN-Li3YBr6 are incompatible with Li, however, an annealing process can improve the electrochemical stability. Both the experimental and simulation results confirm the anode incompatibility between In and AN-Li3YBr6. To mitigate the cathode and anode incompatibility with AN-Li3YBr6, a LiNbO3 coating layer and a Li5.7PS4.7Cl1.3 buffer layer are introduced at the cathode side and anode side, respectively, to assemble all-solid-state batteries with improved capacity and cyclability.

All-inorganic solid-state batteries (AISSBs) have received considerable attention due to their excellent safety and high energy density. However, large interfacial challenges between oxide cathodes and inorganic solid electrolytes dramatically hinder AISSB development. Here we successfully eliminate the long-standing interfacial challenges by in-situ interfacial growth of a highly Li+-conductive halide electrolyte (Li3InCl6, LIC) on the cathode surface. Owing to strong interfacial interaction, high interfacial ionic conductivity (>1 mS cm−1), and excellent interfacial compatibility, LiCoO2 with 15 wt% LIC exhibits a high initial capacity of 131.7 mAh.g−1 at 0.1C (1C = 1.3 mA cm−2) and can be operated up to 4C at room temperature. The discharge capacity retains 90.3 mAh g−1 after 200 cycles. Moreover, a high areal capacity of 6 mAh cm−2 is demonstrated with a high loading of 48.7 mg cm−2. This work offers a versatile approach to eliminate interfacial challenges of AISSBs toward high-energy density and high-power density.

Silicon nanowires (SiNWs) were prepared by the electrochemical reduction of solid Ni/SiO 2 blocks in molten CaCl 2 at 1173 K. The SiNWs have diameter distributions ranging from 80 to 350 nm, and the nickel–silicon droplets are found on the tips of the nanowires. The growth mechanism of SiNWs was investigated, which confirmed that the nano-sized nickel–silicon droplets formed at the Ni/SiO 2 /CaCl 2 three-phase interline. The droplets lead to the oriented growth of SiNWs. Formation of nano-sized nickel–silicon droplets suggests that this method could be a potential way to produce nano-sized metal silicides.

A new positive temperature coefficient (PTC) electrode is prepared simply by coating a thin layer of redox-active poly (3-butylthiophene) (P3BT) in between the electroactive Li[Ni 0.5 Co 0.2 Mn 0.3 ]O 2 [523] layer and the Al foil substrate to improve the safety of lithium-ion batteries. The experimental results demonstrate that the electrical conductivity of the PF 6 − -doped P3BT decreases sharply at 120–150 °C, showing a remarkable PTC effect. As for the P3BT-523 composite electrodes, a rate capacity nearly reaching the reference electrode is obtained at less than 1C rate, while the rate discharge capacities increase obviously with the decrease of the P3BT solution concentration. Moreover, after being exposed to 150 °C for 5 min, the P3BT-523 composite electrodes are hardly discharged and the discharge voltage of the composite electrodes drop drastically below the cut-off voltage at a current density of 3 C, suggesting an effective thermal shutdown switch for lithium-ion batteries.

Various morphologies of silicon nanowires (SiNWs) were successfully prepared by the electrochemical reduction of silica mixed with different additives (Au, Ag, Fe, Co, Ni, and NiO, respectively). Straight SiNWs were extensively obtained by the electro-reduction of porous Ni/SiO2 blocks in molten CaCl2 at 900 °C. The SiNWs had a wide diameter distribution of 80 to 350 nm, and the Ni–Si droplets were found on the tips of the nanowires. The growth mechanism of SiNWs was investigated, which could reveal that the nano-sized Ni–Si droplets formed at the Ni/SiO2/CaCl2 three-phase interlines. Based on the mechanism proposed, NiO particles with sub-micrometer size were selected as the additive, and straight SiNWs with diameters of 60 to 150 nm were also prepared via the electrochemical process.

Solid-state electrolyte and solid-state air electrode design are the main bottlenecks inhibiting the development of solid-state Li–O2 batteries (SSLOBs). Herein, we report an ionically superconductive halide electrolyte which regulates the air electrode interface and enhances the performance of SSLOBs. As this is the first investigation of this halide electrolyte in a Li-O2 battery, a comprehensive study of the stability of this electrolyte is conducted. The high ionic conductivity of Li3InCl6 (up to 1.3 × 10−3 S cm−1) and its solution-based preparation method enable it to work like a liquid electrolyte modifier at the air electrode, uniformly regulating the function of the interface. As a result, Li–O2 batteries with Li3InCl6 exhibit decreased interfacial resistance and enhanced decomposition of discharge products. The present study may open a new window of opportunity toward the development of SSLOBs.

Advancement of all-solid-state lithium-ion (Li+) batteries (ASSLIBs) has been hindered by the large interfacial resistance mainly originating from interfacial reactions between oxide cathodes and solid-state sulfide electrolytes (SEs). To suppress the interfacial reactions, an interfacial coating layer between cathodes and SEs is indispensable. However, the kinetics of interfacial Li+ transport across the coating layer has not been well understood yet. Herein, we tune the interfacial ionic conductivity of the coating layer LiNb0.5Ta0.5O3 (LNTO) by manipulating post-annealing temperature. It is found that the interfacial ionic conductivity determines interfacial Li+ transport kinetics and enhancing the interfacial ionic conductivity can significantly boost the electrochemical performance of SE-based ASSLIBs. A representative cathode LiNi0.5Mn0.3Co0.2O2 coated by LNTO with the highest interfacial ionic conductivity exhibits a high initial capacity of 152 mAh.g−1 at 0.1 C and 107.5 mAh.g−1 at 1 C. This work highlights the importance of increasing interfacial ionic conductivity for high-performance SE-based ASSLIBs.