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The poor ambient ionic transport properties of poly(ethylene oxide) (PEO)-based SPEs can be greatly improved through filler introduction. Metal fluorides are effective in promoting the dissociation of lithium salts via the establishment of the Li–F bond. However, too strong Li–F interaction would impair the fast migration of lithium ions. Herein, magnesium aluminum fluoride (MAF) fillers are developed. Experimental and simulation results reveal that the Li–F bond strength could be readily altered by changing fluorine vacancy (VF) concentration in the MAF, and lithium salt anions can also be well immobilized, which realizes a balance between the dissociation degree of lithium salts and fast transport of lithium ions. Consequently, the Li symmetric cells cycle stably for more than 1400 h at 0.1 mA cm–2with a LiF/Li3N-rich solid electrolyte interphase (SEI). The SPE exhibits a high ionic conductivity (0.5 mS cm–1) and large lithium-ion transference number (0.4), as well as high mechanical strength owing to the hydrogen bonding between MAF and PEO. The corresponding Li//LiFePO4cells deliver a high discharge capacity of 160.1 mAh g–1at 1 C and excellent cycling stability with 100.2 mAh g–1retaining after 1000 cycles. The as-assembled pouch cells show excellent electrochemical stability even at rigorous conditions, demonstrating high safety and practicability.

The composite solid-state electrolytes (CSEs) are one of the most promising electrolytes for advanced solid-state Li metal batteries. However, it is unclear for the effect of the induced electric field inside CSEs on the Li-ion transport. Herein, we design a compact CSE by imbedding the lithium niobate (LiNbO3) with both high ionic conductivity and dielectric constant into poly(vinylidene fluoride) matrix (NPC). The LiNbO3significantly enhances the internal electric field of NPC along the LiNbO3particles and establishes uniform interfacial electric field between NPC and electrodes, which fundamentally facilitates the Li-ion transport, weakens the space-charge layer and inhibits the growth of Li dendrites. Continuous fast ion-conducting channels with high concentration of Li-ions are constructed inside NPC, which contributes to a quite high ionic conductivity (7.39×10−4S cm−1, 25°C) and ultra-low activation energy (0.112 eV). The LiNi0.8Co0.1Mn0.1O2/NPC/Li solid-state batteries exhibit quite stable cycling performance at 25°C.

The ionic conductivity of composite solid-state electrolytes does not meet the application requirements of solid-state lithium (Li) metal batteries owing to the harsh space charge layer of different phases and low concentration of movable Li+. Herein, we propose a robust strategy for creating high-throughput Li+transport pathways by coupling the ceramic dielectric and electrolyte to overcome the low ionic conductivity challenge of composite solid-state electrolytes. A highly conductive and dielectric composite solid-state electrolyte is constructed by compositing the poly(vinylidene difluoride) matrix and the BaTiO3–Li0.33La0.56TiO3–xnanowires with a side-by-side heterojunction structure (PVBL). The polarized dielectric BaTiO3greatly promotes the dissociation of Li salt to produce more movable Li+, which locally and spontaneously transfers across the interface to coupled Li0.33La0.56TiO3–xfor highly efficient transport. The BaTiO3–Li0.33La0.56TiO3–xeffectively restrains the formation of the space charge layer with poly(vinylidene difluoride). These coupling effects contribute to a quite high ionic conductivity (8.2 × 10−4S cm−1) and lithium transference number (0.57) of the PVBL at 25 °C. The PVBL also homogenizes the interfacial electric field with electrodes. The LiNi0.8Co0.1Mn0.1O2/PVBL/Li solid-state batteries stably cycle 1,500 times at a current density of 180 mA g−1, and pouch batteries also exhibit an excellent electrochemical and safety performance.

Solid-state polymer electrolytes (SPEs) are considered as one of the most promising candidates for the next-generation lithium metal batteries (LMBs). However, the large thickness and severe interfacial side reactions with electrodes seriously restrict the application of SPEs. Herein, we developed an ultrathin and robust poly(vinylidene fluoride) (PVDF)-based composite polymer electrolyte (PPSE) by introducing polyethylene (PE) separators and SiO2nanoparticles with rich silicon hydroxyl (Si-OH) groups (nano-SiO2). The thickness of the PPSE is only 20 μm but possesses a quite high mechanical strength of 64 MPa. The introduction of nano-SiO2fillers can tightly anchor the essential N,N-dimethylformamide (DMF) to reinforce the ion-transport ability of PVDF and suppress the side reactions of DMF with Li metal, which can significantly enhance the electrochemical stability of the PPSE. Meanwhile, the Si-OH groups on the surface of nano-SiO2as a Lewis acid promote the dissociation of the lithium bis(fluorosulfonyl)imide (LiFSI) and immobilize the FSI–anions, achieving a high lithium transference number (0.59) and an ideal ionic conductivity (4.81 × 10–4S cm–1) for the PPSE. The assembled Li/PPSE/Li battery can stably cycle for a record of 11,000 h, and the LiNi0.8Co0.1Mn0.1O2/PPSE/Li battery presents an initial specific capacity of 173.3 mA h g–1at 0.5 C, which can stably cycle 300 times. This work provides a new strategy for designing composite solid-state electrolytes with high mechanical strength and ionic conductivity by modulating their framework.

The low ionic conductivity of composite solid-state electrolytes due to the lack of free Li-ions and Li dendrite growth induced by the low transference number seriously hinder their application. Herein, we find that the giant dielectric ceramic of Li0.3Ti0.02Ni0.68O (LTNO) with ultra-high dielectric constant can greatly promote the dissociation of Li salt to generate abundant movable Li-ions and realize a high room-temperature ionic conductivity (4.09 × 10–4S cm−1) as well as a low activation energy (0.16 eV). The oxygen vacancies on the surface of LTNO can effectively immobilize the anions to achieve a high Li transference number (0.61). Furthermore, the enhanced dielectric properties of the composite electrolyte induce homogenous Li plating/stripping to suppress the growth of Li dendrites. As a result, the Li||Li symmetric cells exhibit long lifespan of 2400 h and 1150 h at 0.1 mA cm−2and 0.2 mA cm−2, respectively. The Li||LiNi0.8Co0.1Mn0.1O2solid-state full cells show a high capacity retention of 83% after 430 cycles at 2C. This work highlights the critical role of high dielectric property and oxygen defects of fillers in composite solid-state electrolytes, and provides a demonstration for the application of giant dielectric materials in solid-state Li metal batteries.

The coupling of high-capacity cathodes and lithium metal anodes promises to be the next generation of high-energy-density batteries. However, the fast-structural degradations of the cathode and anode challenge their practical application. Herein, we synthesize an electrolyte additive, tris(2,2,3,3,3-pentafluoropropyl) borane (TPFPB), for ultra-stable lithium (Li) metal||Ni-rich layered oxide batteries. It can be preferentially adsorbed on the cathode surface to form a stable (B and F)-rich cathode electrolyte interface film, which greatly suppresses the electrolyte-cathode side reactions and improves the stability of the cathode. In addition, the electrophilicity of B atoms in TPFPB enhances the solubility of LiNO3by 30 times in ester electrolyte to significantly improve the stability of the Li metal anode. Thus, the Li||Ni-rich layered oxide full batteries using TPFPB show high stability and an ultralong cycle life (up to 1500 cycles), which also present excellent performance even under high voltage (4.8 V), high areal mass loading (30 mg cm−2) and wide temperature range (−30∼60°C). The Li||LiNi0.9Co0.05Mn0.05O2(NCM90) pouch cell using TPFPB with a capacity of 3.1 Ah reaches a high energy density of 420 Wh kg−1at 0.1 C and presents outstanding cycling performance.Boron-based electrolyte additives are preferentially adsorbed on cathode surface to form a stable cathode electrolyte interface, which greatly suppresses side reactions of electrolyte with high-voltage cathode and improves their stability.

The practical use of lithium–sulfur (Li–S) batteries is limited by serious self-discharge, fast capacity loss, and severe lithium anode erosion due to the shuttling of lithium polysulfides (LiPSs). Herein, we developed a highly efficient ion and electron conductive interlayer composed of Ti2(SO4)3/carbon composite layer-coated Li1.3Al0.3Ti1.7(PO4)3(CLATP) and graphene to effectively block the diffusion of polysulfide anions but allow rapid Li ion transfer, therefore significantly inhibiting the self-discharge and boosting the cyclic stability of Li–S batteries. The Ti2(SO4)3/carbon thin protective layer endows an optimized adsorption ability toward LiPSs and avoids the side reactions between LATP and LiPSs. The high electronic conductivity of graphene and high ionic conductivity of CLATP ensures the hybrid interlayer rapid electron and fast Li ion transport. As a result, the Li–S battery with the hybrid interlayer shows a high discharge capacity of 671 mAh g–1after 500 cycles with an extremely low capacity fading of 0.022% per cycle at 1 C. Moreover, the battery shows no self-discharge even after rest for 12 days. This work opens up a new way for the design of functional separators to significantly improve the electrochemical performance of Li–S batteries.

The severe lithium (Li) dendrite growth leads to poor cycling stability and serious safety hazards of Li metal batteries, which completely impedes their practical applications. Herein, a novel Li nucleation-diffusion-growth mechanism based on Li-Sn alloy/Li3N electrolyte (LS/LN) composite interface layer is proposed, which synergistically guides the horizontal deposition of Li to suppress the vertical growth of Li dendrite and side reactions with the electrolyte. The lithiophilic Li-Sn alloy captures Li ions to nucleate preferentially on the alloy sites, and simultaneously the Li3N with low diffusion energy barrier and high Li-ion conductivity efficiently transports Li ions to nucleation sites during Li plating, consequently promoting the Li horizontal deposition. As a result, the LS/LN-Li symmetric cells can stably cycle 1600 h even at a high current density of 5 mA cm−2and deposition capacity of 5 mA h cm−2. The LiFePO4∣LS/LN-Li cells with a high loading of 8.2 mg cm−2present a high capacity retention of 93.4% after 1000 cycles, much higher than that using bare Li (64.8%). Furthermore, the LiNi0.8Co0.1Mn0.1O2∣LS/LN-Li cells present more excellent cycling stability than the cells using bare Li. The Li nucleation-diffusion-growth mechanism opens a promising route to solve the challenge of the vertical growth of Li dendrite and achieve highly stable Li metal batteries.

Enormous research focusing on solid-state electrolyte promotes the development of solid-state batteries. Compared to lithium-ion batteries using liquid electrolyte, the solid-state batteries feature the high energy density and non-flammability, which accelerates the revolution in portable electronics and transportation. Garnet-type Li7La3Zr2O12(LLZO) solid-state electrolyte is considered as the promising solid-state electrolyte due to high ionic conductivity, Li transference number and shear modulus. However, surface contaminant and poor contact with lithium inhibit its practical application in lithium metal batteries. The review provides a brief introduction about structure and properties of LLZO. Then, we conclude the modification strategies for increasing ionic conductivity, enhancing interfacial contact and inhibiting lithium dendrite. At last, the challenge and perspectives are discussed for development of LLZO in solid-state batteries.

The charge storage mechanism of α-Mn2O3as cathode of aqueous Zinc-ion batteries greatly depends on the discharge current density and its discharging products present obviously different morphologies changing from flower-like to large plate-like products.

All-solid-state batteries have become the most potential next-generation energy-storage devices. However, it is quite difficult to simultaneously achieve a single solid-state electrolytes (SSEs) layer with both dendrite-free Li metal plating and low interfacial resistance between the cathode and SSEs. Herein, an integrated structure of cathode and double-layer solid electrolyte membrane (IS-CDL) is designed, which greatly improves the interfacial contact and suppresses the Li dendrite growth. The first “polymer in ceramic” solid electrolyte layer (SL1) consists of 80 wt % Li1.4Al0.4Ti1.6(PO4)3(LATP) nanoparticles and 20 wt % polyethylene oxide (PEO), and the second polymer electrolyte layer is PEO-based solid electrolyte layer (SL2). The SL1 with high mechanical properties can hinder the growth of Li dendrites and reduce the interfacial resistance with the cathode. The SL2 can inhibit the side reaction between the Li metal and LATP. The Li symmetric cells with sandwich-type hierarchical electrolyte (SL2/SL1/SL2) can stably cycle over 3200 h at 0.1 mA cm–2at 45 °C. The obtained all-solid-state LiFePO4–IS-CDL/Li batteries present a capacity of 142.6 mA h g–1at 45 °C with the capacity retention of 91.7% after 100 cycles, and all-solid-state NCM811–IS-CDL/Li batteries deliver a specific capacity of 175.5 mA h g–1at 60 °C. This work proposes an effective strategy to fabricate all-solid-state lithium batteries with high electrochemical performance.

To boost the energy density as well as address the safety issues, an effective strategy is to replace the liquid electrolytes with solid-state electrolytes (SSEs). However, the current SSEs usually show low ionic conductivity at room temperature and large interfacial impedance with electrodes, which hinders the operation of the all-solid-state lithium batteries (ASSLBs) at room temperature. In this Review, we summarize the recent progress related the fundamental properties, preparation techniques, and electrochemical performance of room-temperature ASSLBs using different types of SSEs, such as polymer-based, oxides-based, and sulfides-based SSEs. We analyze the progress in resolving the issues associated with the low ionic conductivity of polymer-based SSEs and high interfacial resistance and instability of inorganic SSEs. Furthermore, the key issues and critical perspectives to develop high-performance ASSLBs at room temperature are discussed.

We prepared a cross-linked binder for the cathode of Lithium-Sulfur battery by in-situpolymerizing polycarbonate diol (PCDL), triethanolamine (TEA) and hexamethylene diisocyanate (HDI) through a facile method. The binder could effectively restrain the volume expansion of S cathode and the shuttle effect of polysulfide.

Recently, crystal-phase engineering has been emerging as a promising strategy to tune the physicochemical properties of noble metal catalysts and further improve their catalytic performance. However, the synthesis of noble metal catalysts with an unconventional crystal phase as well as desired composition and morphology still remains a great challenge. Herein, a series of PdM (M = Zn, Cd, ZnCd) nanosheets (NSs) with thickness less than 5 nm have been synthesized viaa facile one-pot wet-chemical method. In particular, different from the conventional face-centered cubic (fcc) phase, PdM NSs possess an unconventional face-centered tetragonal (fct) phase. As a proof-of-concept application, the fctPdZn NSs exhibit significantly enhanced mass activity and stability in ethanol oxidation reaction, compared to the pure Pd NSs and commercial Pd black catalyst.

Li4Ti5O12(LTO) as the anode of lithium (Li) ion batteries has high interfacial side reactivity with the electrolyte, which leads to severe gassing behavior and poor cycling stability. Herein, the capacity loss mechanism of the high-tap density LTO microsphere anode under different temperatures (25, 45, and 60 °C) and charge/discharge rates (1 and 5 C) is systematically investigated. The capacity retentions of the LTO/Li cell after 500 cycles at 1 C are 95.6, 90.0, and 87.1% under three temperatures, which drop to 91.9, 58.3, and 20.9% when cycling at 5 C, respectively. Results show that the high temperature and rate almost do not damage the structure of LTO, but greatly affect the thickness and components of the solid electrolyte interface (SEI), and consequently reduce the performance of the LTO/Li cells. An SEI mainly consisting of inorganic species forms on LTO after 500 cycles at 1 C, while organic compounds are observed after 500 cycles at 5 C. The capacity of cycled LTO cannot recover again because of the thick SEI although using new Li metal anodes, separators, and electrolytes. This work demonstrates that it is of great significance for LTO to construct a stable SEI for achieving excellent cycling performance at a high rate and temperature.

Designing composite structures of active materials is critical for high-performance lithium-ion batteries, as it determines the reversibility of lithium-ion insertion and extraction of the electrodes. The V2O3anode has a high specific capacity but presents poor cycling stability due to a large volume change. Herein, a novel C@V2O3–Li4Ti5O12composite with ultrastable cycling stability is constructed. In this composite structure, the interconnected ultrasmall V2O3and Li4Ti5O12nanoparticles (5–10 nm) construct robust interfaces in the carbon matrix. The Li4Ti5O12nanoparticles with excellent cycling stability and a minor volume change act as fixtures that effectively restrict the volume change of V2O3nanoparticles and improve the cycling stability of the C@V2O3–Li4Ti5O12composite. The C@V2O3–Li4Ti5O12composite maintains no degradation during 500 cycles under a current density of 100 mA g–1. The results demonstrate that constructing a highly stable interface between the active nanoparticles with smaller and larger volume changes is of great significance to suppress their pulverization and achieve high reversibility. This work contributes to a new strategy to design the structure of long-cycling anode materials for highly stable lithium-ion batteries.

Severe capacity fading and poor high rate performance of lithium sulfur (Li–S) battery caused by “shuttle effect” and low conductivity of sulfur hampers its further developments and applications. Li4Ti5O12(LTO) possesses high lithium ion conductivity, and it is also can be used as an active adsorbent for polysulfide. Herein, fine LTO particle coated carbon nanofibers (CNF) were prepared and a conductive network both for electron and lithium ion was built, which can greatly promote the electrochemical conversion of polysulfide and improve the rate performance of Li–S batteries. Meanwhile, a quantity of adsorption sites is constructed by defects of the surface of LTO-CNF membrane to effectively immobilize polysulfide. The multifunctional LTO-CNF interlayer could impede the shuttle effect and enhance comprehensive electrochemical performance of Li–S batteries, especially high rate performance. With such LTO-CNF interlayer, the Li–S battery presents a specific capacity of 641.9 mAh/g at 5 C rate. After 400 cycles at 1 C, a capacity of 618.0 mAh/g is retained. This work provides a feasible strategy to achieve high performance of Li–S battery for practical utilization.

Solid electrolytes are considered as strong alternatives for conventional liquid electrolytes to overcome the safety issues of next-generation high-energy-density lithium metal batteries (LMBs). Although Li1.5Al0.5Ge1.5(PO4)3(LAGP) has satisfied ionic conductivity at room temperature (∼10–4S cm–1), high stability in air, and can be easily sintered, it still suffers from instability of the lithium metal. Moreover, the large interfacial resistance between solid electrolytes and solid electrodes and the stress generated by the volumetric change of lithium metal anodes during cycling would deteriorate the performance of LMBs. Here, we report an effective solution to overcome the abovementioned problems by introducing a three-dimensional gel polymer electrolyte at the interface between LAGP pellets and lithium metal anodes, achieving stable cycling of LiFePO4//Li cells at room temperature for 300 cycles. Besides, the degeneration mechanisms of the interfaces of LAGP pellets under different conditions are compared, and peculiar properties different from their counterparts were found.

Poly(vinylidene fluoride) (PVDF)-based solid electrolytes with a Li salt-polymer-little residual solvent configuration are promising candidates for solid-state batteries. Herein, we clarify the microstructure of PVDF-based composite electrolyte at the atomic level and demonstrate that the Li+-interaction environment determines both interfacial stability and ion-transport capability. The polymer works as a “solid diluent” and the filler realizes a uniform solvent distribution. We propose a universal strategy of constructing a weak-interaction environment by replacing the conventional N,N-dimethylformamide (DMF) solvent with the designed 2,2,2-trifluoroacetamide (TFA). The lower Li+binding energy of TFA forms abundant aggregates to generate inorganic-rich interphases for interfacial compatibility. The weaker interactions of TFA with PVDF and filler achieve high ionic conductivity (7.0 × 10–4S cm–1) of the electrolyte. The solid-state Li||LiNi0.8Co0.1Mn0.1O2cells stably cycle 4900 and 3000 times with cutoff voltages of 4.3 and 4.5 V, respectively, as well as deliver superior stability at −20 to 45 °C and a high energy density of 300 Wh kg–1in pouch cells.

Oxide solid-state electrolytes (OSEs) with high ionic conductivity, wide electrochemical window and inherent safety are critical to achieve high-energy-density and safe performance of solid-state batteries (SSBs). However, the large interfacial impedance and severe side reactions between OSEs and electrodes remain challenging for ion transport in SSBs, which is attributed to the poor physical contact and chemical compatibility between OSEs and electrode materials. In this review, the recent research on solid-state interfaces in SSBs is summarized and discussed. These strategies can be categorized into interfacial structure design and interfacial modifications. Structure designs, including constructing architectural Li anode, three-dimension (3D) structure OSEs and integrated cathode can significantly increase the effective contact area between electrodes and OSEs to facilitate the interfacial ion transport. The interfacial modifications are utilized to improve the wettability of OSEs for lithium metal anode, enhance the interfacial ion transport, and stabilize the OSEs/electrodes interface. Interface architecture is crucial to enhance structural stability and reduce interface impedance for advanced oxide-based SSBs. At last, the future research direction of interfacial modification in SSBs is prospected.

Lithium metal is considered to be the most promising anode material for the next-generation rechargeable batteries. However, the uniform and dendrite-free deposition of Li metal anode is hard to achieve, hindering its practical applications. Herein, a lightweight, free-standing and nitrogen-doped carbon nanofiber-based 3D structured conductive matrix (NCNF), which is characterized by a robust and interconnected 3D network with high doping level of 9.5 at%, is prepared by electrospinning as the current collector for Li metal anode. Uniform Li nucleation with reduced polarization and dendrite-free Li deposition are achieved because the NCNF with high nitrogen-doping level and high conductivity provide abundant and homogenous metallic Li nucleation and deposition sites. Excellent cycling stability with high coulombic efficiency are realized. The Li plated NCNF was paired with LiFePO4to assemble the full battery, also showing high cyclic stability. 锂金属是未来二次电池实现高能量密度化的关键负极材料, 然而, 如何实现锂金属的均匀和无枝晶沉积是目前制约其实际应用的关键问题. 本论文采用静电纺丝技术及高温碳化方法制备了一种轻质、 高掺氮量(9.5 at%)的三维碳纳米纤维集流体. 该集流体较低的密度能提升基于整个电池的能量密度, 而且高掺氮量使其具备亲锂的特性, 从而有效降低锂离子在其表面的初始形核过电位, 得到均匀的金属锂种子层, 实现后续金属锂的均匀沉积. 这种三维结构有效抑制了锂枝晶的产生, 降低了电池的极化, 金属锂沉积/脱除测试中其库伦效率在循环250圈后仍可保持在98%以上. 将其沉积金属锂后与LiFePO4组装全电池, 电池极化降低, 在循环300圈后容量保持率可达82.4%, 表现出很好的应用前景.

Bismuth (Bi), a uniquely stable pnictogen element, is deemed a promising anode material for lithium-ion batteries owing to its high volumetric capacity, moderate operating voltage and environmental friendliness. However, the application of Bi as anode is hindered by its low conductivity and large volume change during cycling. Herein, we introduce an advanced surface engineering strategy to construct Bi@C-TiOxmicrospheres encapsulated by ultra-large graphene interfacial layer. Ultrafine Bi nanoparticles are confined and uniformly dispersed inside the C-TiOxmatrix, which is the pyrolysis derivative of the newly developed Bi-Ti-EG bimetal organic frameworks, with the aid of a selective graphene interfacial barrier. A three-dimensional (3D) long-range conductive network is successfully constructed by the ultra-large graphene and the carbonized derivative of Bi-Ti-EG. Additionally, the 3D carbon network and the in-situ formed TiOxcoupled with a porous structure act as soft buffer and hard suppressor to alleviate the huge volume change of Bi during cycling, and they also are the important electrochemically active components. Thanks to the synergistic effects intrigued by the aforementioned interfacial engineering strategy, the newly developed ultra-large graphene encapsulated Bi@C-TiOxmicrospheres exhibit an exceptional superpower and outstanding cycle stability (namely, 333.3, 275 and 225 mAh g−1at 1, 5 and 10 A g−1, respectively, with remarkable capacity retention upon 5000 cycles), surpassing other reported Bi-based anode materials so far. This study underpins that the nanoscale surface design of electrode materials for batteries is an effective approach to significantly enhance the power capability, capacity and cyclic stability of new metal anodes.

The relentless development and modularization of electronics have urgently required the all-round improvement of performance, flexibility, safety, miniaturization and integration of micro-batteries. However, traditional cell design in stacked geometry fails to meet these comprehensive demands, especially high-temperature performance. Herein, we report the prototype construction of all-solid-state planar lithium ion micro-batteries (LIMBs), with characteristics of superior volumetric energy density, exceptional flexibility, extraordinary high-temperature performance, and outstanding integration of bipolar cells. The planar LIMBs were manufactured based on the interdigital patterns of lithium titanate nanospheres/graphene as anode and lithium iron phosphate microspheres/graphene as cathode, free of polymer binder and separator, working in ionogel electrolyte. The resulting LIMBs deliver ultrahigh volumetric energy density of 125.5 mWh cm−3, ultralong-term cyclability without capacity loss after 3300 times at room temperature, and outstanding rate capability due to the multi-directional Li-ion diffusion mechanism. Furthermore, our micro-batteries present exceptional flexibility without capacity decay under repeated bending, remarkable high-temperature performance up to 1000 cycles operated at 100 °C, superior miniaturization and simplified modularization of constructing intergrated LIMBs that readily control over the output voltage and capacity, all of which can’t be simultaneously achieved by the conventional techniques. Therefore, our planar LIMBs hold tremendous opportunities for future miniaturized and integrated electronics.

The severe lithium polysulfide (LiPS) shuttling and self-discharge behavior of lithium-sulfur (Li-S) batteries remarkably hinder their practical application. The construction of interlayer is an effective strategy to obstruct the diffusion of LiPS. However, the simplex physical block or chemical absorption of monotonous interlayer is difficult to reuse sulfur species, reduce impedance and restrain self-discharge of the Li-S battery simultaneously. In this study, a multicomponent sandwich-type interlayer was integrated by vanadium disulfide and carbon nanotubes composite (VS2/CNT), carbon nanofibers (CNF) substrate and graphene coating layer. The VS2/CNT presented strong affinity towards LiPS and effectively restrained the self-discharge of Li-S batteries. The CNF substrate as supporting framework increased the wettability of electrolyte and reduced the diffusion impedance of lithium ion. The graphene coating layer acting as the second collector effectively recovered the inactivated sulfur species. The multiple components of VS2/CNT adsorbent, CNF substrate and graphene coating layer exhibited favorable synergetic effects to suppress the LiPS shuttling and self-discharge of Li-S batteries. Besides, this interlayer endowed Li-S batteries with boosted redox kinetics and outstanding rate performance. The specific capacities at 0.1, 1 and 10 C were 1525, 834 and 621 mAh g−1, respectively. More importantly, the Li-S batteries with this multicomponent interlayer performed a high residual capacity of 605 mAh g−1after 1145 cycles at 1 C. Even at a high sulfur loading of 5.6 mg cm−2, the cell still had high capacity of 1150 mAh g−1and 750 mAh g−1at 0.1 C and 0.3 C, respectively. The synergetic effects of multicomponent sandwich-type composite interlayer provided a new strategy for ultra-small self-discharge and stable of Li-S batteries.

A nitrogen (N)-doped porous carbon sheet is prepared by in situ polymerization of pyrrole on both sides of graphene oxide, following which the polypyrrole layers are then transformed to the N-doped porous carbon layers during the following carbonization, and a sandwich structure is formed. Such a sheet-like structure possesses a high specific surface area and, more importantly, guarantees the sufficient utilization of the N-doping active porous sites. The internal graphene layer acts as an excellent electron pathway, and meanwhile, the external thin and porous carbon layer helps to decrease the ion diffusion resistance during electrochemical reactions. As a result, this sandwich structure exhibits prominent catalytic activity toward the oxygen reduction reaction in alkaline media, as evidenced by a more positive onset potential, a larger diffusion-limited current, better durability and poison-tolerance than commercial Pt/C. This study shows a novel method of using graphene to template the traditional porous carbon into a two-dimensional, thin, and porous carbon sheet, which greatly increases the specific surface area and boosts the utilization of inner active sites with suppressed mass diffusion resistance.

Porous current collectors are conducive to enhance the property of Li metal anode. Unfortunately, congestion in diffusion path during plating process damages the effects of current collectors. Herein, we developed a 3D Cu skeleton with open micrometer-sized pores by NaCl-assisted powder-sintering method. The unobstructed pores of 3D Cu skeleton help to reduce congestion during plating, thus most of Li deposited inside the current collector. Besides, the large smooth surface promotes the deposition of Li with smooth spherical shape, which mitigating Li dendrite growth. As a result, better safety and rechargeability of Li metal anode were achieved in this design.

Abstract

The development of efficient oxygen evolution reaction (OER) electrocatalysts is of vital importance for acidic water decomposition. Currently, the rutile structured RuO2is considered to be the best candidate and has been studied widely. However, the state-of-the-art rutile RuO2still suffers from unsatisfactory activity and stability, while other crystalline structures of Ru-based oxides are seldom reported as OER electrocatalysts. The present work, for the first time, successfully synthesizes orthorhombic (Ru, Mn)2O3electrocatalyst through cation exchange. The orthorhombic (Ru, Mn)2O3particles exhibit the outstanding electrocatalysis performance as OER electrocatalyst, showing an ultralow overpotential of 168 mV at 10 mA cm−2in acidic water and good stability in 40 h of OER. The outstanding electrocatalysis performance is attributed to the distinct Ru d-band structure together with the larger surface density of Ru active site, which reduces the free energy of the rate-limiting step during OER.

Small amounts of two-dimensional (2D) graphene sheets are usually added into a polymer matrix to fabricate nanocomposites with improved mechanical and functional properties. Further enhancements of these properties beyond those of ordinary nanocomposites require much higher loadings of well-dispersed fillers, preferably in the form of an interconnected network with the preferential orientation along the direction of interest. However, the assembly of 2D fillers to form such a three-dimensional (3D) network remains a formidable task. Herein, a totally new approach is developed to fabricate a high-density 3D multilayer graphene web with interconnected, in-plane oriented graphene struts based on the versatile chemical vapor deposition technique. The continuous high-quality graphene network within the epoxy composites leads to exceptional electrical and thermal conductivities of 50 S cm−1and 8.8 Wm−1K−1, respectively. The high filler loading of 8.3 wt% also gives rise to a remarkable fracture toughness of 2.18 MPa m1/2, well over 100% enhancement over the neat epoxy. The simultaneous achievements of both remarkable transport properties and fracture toughness at these levels by an identical nanocomposite are unprecedented and have never been reported previously. The combination of unrivalled electrical and thermal conductivities with extraordinary fracture resistance offers the composites unique opportunities for multi-functional applications.

Vanadium pentoxide (V2O5) is considered a promising cathode material for advanced lithium-ion batteries owing to its high specific capacity and low cost. However, the application of V2O5-based electrodes has been hindered because of their inferior conductivity, cycling stability, and power performance. Herein, hierarchical sisal-like V2O5microstructures consisting of primary one-dimensional (1D) nanobelts with [001] facets orientation growth and rich oxygen vacancies are synthesized through a facile hydrothermal process using polyoxyethylene-20-cetyl-ether as the surface control agent, followed by calcination. The primary 1D nanobelt shortens the transfer path of electrons and ions, and the stable {001} facets could reduce the side reaction at the interface of electrode/electrolyte, simultaneously. Moreover, the formation of low valence state vanadium would generate the oxygen vacancies to facilitate lithium-ion diffusion. As a result, the sisal-like V2O5manifests excellent electrochemical performances, including high specific capacity (297 mA h g–1at a current of 0.1 C) and robust cycling performance (capacity fading 0.06% per cycle). This work develops a controllable method to craft the hierarchical sisal-like V2O5microstructures with excellent high rate and long-term cyclic stability.

Among various two-dimensional compounds, transition metal dichalcogenides (TMDs or MX2) are a group of materials attracting growing research interest for potential applications as battery electrodes. Here we systematically investigate the electrochemical performance of a series of MX2(M = Mo, W, Nb, Ta; X = S, Se) upon Li/Na intercalation through first-principles calculations. MoX2and WX2were found to have lower voltages while those of NbX2and TaX2were higher than 1.5 V. By applying the rigid-band model, we found that the energy gained for electrons to transfer from Li/Na to MX2could serve as a descriptor for characterizing voltages of MX2.The linear relation between the descriptor and voltages is useful for screening candidates for electrodes with desired voltage. Migration barriers for Li/Na ions were approximately 0.3 eV in MoX2/WX2and 0.5 eV in NbX2/TaX2. The low barriers suggest a reasonable rate performance when these TMDs are used as electrodes. By stacking different MX2with distinct properties, TMDs heterostructures could be adopted to provide tunable electrochemical properties, including voltage, capacity and electronic conductivity while keeping barriers for Li/Na ions little changed. Thus, this strategy offers another degree of freedom for rational design of layered electrode materials.

The rapid development of lithium (Li)-ion and sodium (Na)-ion batteries requires advanced solid electrolytes that possess both favorable electrochemical performance and safety assurance. Herein we report a hierarchical poly (ionic liquid)-based solid electrolyte (HPILSE) for high-safety Li-ion and Na-ion batteries. This hybrid solid electrolyte is fabricated via in situ polymerizing 1,4-bis[3-(2-acryloyloxyethyl)imidazolium-1-yl]butane bis[bis(trifluoromethanesulfonyl)imide] (C1-4TFSI) monomer in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMITFSI)-based electrolyte which is filled in poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PDDATFSI) porous membrane. The well-designed hierarchical structure simultaneously provides the prepared HPILSE with high ionic conductivity (>10−3Scm−1at 25°C), satisfied electrochemical stability, inherent incombustibility, good mechanical strength and flexibility. More intriguingly, the in situ assembled LiFePO4/Li and Na0.9[Cu0.22Fe0.30Mn0.48]O2/Na cells using HPILSE exhibit superior cycling performances with high specific capacities. Both the excellent performance of HPILSE and the simple fabricating process of HPILSE-based solid-state cells make it potentially as one of the most promising electrolyte materials for next generation Li-ion and Na-ion batteries.