The urgent demand for high energy and safety batteries has generated the rapid development of Li6.4La3Zr1.4Ta0.6O12 (LLZTO) type solid-state lithium metal batteries. However, severe dendritic lithium growth, which is caused by poor interfacial contact of the Li/LLZTO interface and loss of electrical contact during cycles due to low intrinsic Li+ diffusion coefficient of lithium, greatly hampers its practical application. Here, from the point of view of reducing surface tension and improving ion diffusion of lithium, a composite lithium anode (CLA) with high wettability and ion diffusion coefficient is prepared by adding GaP into molten lithium, thus strengthening the CLA/LLZTO interface even in cycling. As envisioned, compared to pure lithium, CLA presents lower surface tension, larger adhesion work, and higher ion diffusion coefficient, ensuring close contact of the CLA/LLZTO interface. Therefore, the assembled symmetric cells exhibit a low area specific resistance of 4.5 Omega cm(2), a large critical current density of 2.5 mA cm(-2), and ultra-long lifespan of 5700 h at 0.3 mA cm(-2) at 25 degrees C. Meanwhile, full cells coupled with LiFePO4 cathode show a high-capacity retention of 97.32% after 490 cycles at 1C. This work provides a new solution to the interfacial challenges of solid-state lithium-metal batteries.

Li6.4La3Zr1.4Ta0.6O12 (LLZTO) based solid-state lithium metal batteries (SSLMBs) have a broad application prospect because of the nonflammable nature as well as the high energy density. However, the loose contact and the contact degradation of Li/LLZTO in the stripping process result in the serious lithium dendrites growth. Herein, these issues are addressed by a composite lithium anode (CLA), which is prepared through the reaction between black phosphorus and molten lithium. In comparison to pure lithium, a higher adhesion work (722.67 mJ m-2) and Li+ diffusion coefficient (2.45x10- 12 cm2 s-1) are achieved for CLA, thus assuring the intimate interfacial contact of CLA/LLZTO interface during the lithium stripping process. As a result, a small interfacial resistance of 3.7 Omega cm2, a high critical current density of 1.5 mA cm- 2, and extra-long cycle life of 8200 h at 0.3 mA cm- 2 are achieved for CLA symmetric cell at 25 degrees C. More importantly, the full cell coupled with high mass loading LiFePO4 cathode (10.6 mg cm-2) still shows a large discharge capacity of 156.3 mAh g-1 and cycles stably at 25 degrees C. This work provides an alternative approach to develop the long lifespan and high capacity of SSLMBs.

This paper proposes to prepare hydrophobic alkali-activated slag (AAS) mortars with methyl-terminated polydimethylsiloxane (PDMS), a hydrophobic polymer with low surface energy, to minimize its water sorptivity and efflorescence. To depict the efflorescence process of PDMS-modified AAS mortars, visual inspections of efflorescence features, the leaching behavior of sodium ions, water absorption characteristics of mortars and contact angle tests were conducted. Additionally, the hydration process, microscopic morphology, and chemical structure of PDMS-modified AAS mortars and pastes were examined by compressive strength, isothermal calorimetry, TEM, SEM, FT-IR, 29 Si NMR, enabling the explanation of PDMS working mechanisms. The results demonstrated that the addition of PDMS successfully mitigated esthetic issues and the spalling of mortars caused by efflorescence. Furthermore, PDMS reduced the risk of long-term durability issues of AAS mortars by restricting the loss of sodium ions after efflorescence. At the same time, the introduction of PDMS with dosage below 5 % did not significant retarder the hydration reaction process or the development of strength of AAS. However, it did alter the micromorphology and chemical structure of the hydration product. PDMS linked to the hydration products through covalent bonds and acted as a bridging role to alter the micromorphology of the hydration products. The resulting multi-structured material exhibited micropapillary and nano-coating layers with hydrophobic methyl functional groups, imparting hydrophobicity to the PDMS-AAS hydration product.

Solid-state lithium metal batteries (SSLMBs) are regarded as an important development direction due to their high energy density and safety. Nevertheless, the application of SSLMBs is hampered by the poor interfacial contact with large resistance and dendrite issue, as well as volume variation of metallic lithium anode. Here, a high-performance Li-BiF3 composite lithium having successive ion-conducting phase was constructed via the conversion reaction between commercial BiF3 powders and molten lithium, which shows reduced surface tension of lithium and improved wettability toward Li6.4La3Zr1.4Ta0.6O12 electrolytes. The as-formed Li3Bi in the anode with high ionic diffusion coefficient can quickly transport lithium from the bulk to the solid-state interface to compensate for the lithium depletion during stripping, thus ensuring tight interface contact, inhibiting the generation of gaps, and homogenizing current and Li+ flux. The Li-BiF3/LLZTO/Li-BiF3 symmetric cells present small interfacial resistance (7.4 omega cm2), large critical current density (1.1 mA cm-2) and superior cyclic stability of 850 h under 0.3 mA cm-2 at 25 degrees C. In addition, full cells assembled together with LiFePO4 and LiNi0.8Co0.1Mn0.1O2 cathodes demonstrate exceptional cyclic performance with 92.9% and 86.5% capacity maintenance upon 100 cycles under 0.5 C.

Introducing sodium as anode to develop sodium metal batteries (SMBs) is a promising approach for improving the energy density of sodium‐ion batteries. However, fatal problems, such as uncontrollable sodium dendrite growth, unstable solid electrolyte interphase (SEI) in low‐cost carbonate‐based electrolytes, and serious safety issues, greatly impede the practical applications. Here, a multifunctionalized separator is rationally designed, by coating PP separator (<25 µm) with a solid‐state NASICON‐type fast ionic conductor layer (NZSP@PP) to replace the widely used thick glass fiber separator (>200 µm) and successfully solves all of the above problems, and for the first time creats high performance SMBs by using Na 3 V 2 (PO 4 ) 3 (NVP) cathodes in pouch cell. The Na||NVP full cells can stably cycle over 1200 times with capacity retention of 80% at a high rate of 10 C and deliver a specific capacity of 80 mAh g −1 even at high rate of 30 C, indicating extraordinary fast‐charging characters. The full SMBs can also stably cycle 200 times with a retention of 96.4% under high NVP loading of 10.7 mg cm −2 . Most importantly, the SMB pouch cell can also deliver a long‐life cycles as well as high‐temperature battery performance, which guarantees the safety of SMBs in practical application.

Lithium-ion capacitors (LICs) possess high energy density and power density simultaneously. However, for balancing electrochemical performance, mechanical properties and safety issues, the development of highperformance electrodes and electrolytes is still a challenge in this field. Herein, a 3D nitrogen-doped carbonaceous foam (N-C) was synthesized by chemical vapor deposition (CVD), and the covering of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) dramatically increase its flexibility without decreasing the electrochemical performance. The complete quasi-solid-state LICs using N-C/PVDF-HFP as anode, N-C/activated carbon (AC)/PVDF-HFP as cathode and PVDF-HFP as the skeleton of gel electrolyte are fabricated and shows good cycle stability (72.2 % after 2000 cycles). Meanwhile, the power density of the LIC can reach up to 342.5 W/kg when the energy density is 209.3 Wh/kg, and the power density can reach as high as 7632.2 W/kg at energy density of 77.6 Wh/kg, which is higher than many other dual-carbon and quasi-solid-state LICs.

The use of Li anode is critical for the energy density of solid-state Li-metal batteries (SSLMBs) to surpass that of lithium-ion batteries. However, the practical applications are hampered by the large interfacial resistance and poor physical contact at the solid-state interface, as well as dendrite issues and volume changes of Li anode. Here, a composite lithium anode with continuous electron/ion conductive networks is fabricated, which shows a significant improvement in wettability towards garnet-type Li6.4La3Zr1.4Ta0.6O12 electrolytes. The intimate interface and its high charge-transfer kinetics of composite Li anode endows the symmetric cell a small over -potential (45 mV) at 0.3 cm(-2), ultra-low interfacial resistance (-2.0 omega cm(2)), high critical current density (1.1 mA cm(-2)), and outstanding cycling performance (> 3000 h at 0.1 mA cm(-2)) at 25 ?. The SSLMB paired with LiFePO4 delivers a high discharge specific capacity of 161.7 mAh g(-1) at 0.1 C, good cycle performance of 100 cycles with capacity retention of 80%. Moreover, the NMC811-based SSLMB can also realize a high capacity of 219.5 mAh g(-1), superior rate capability and cyclic stability. This work lays the foundation to develop composite Li anodes for practical applications of SSLMBs with high performance.

In this work, a lithiophilic Ni-Al@LDH interlayer is engineered at the Li6.4La3Zr1.4Ta0.6O12 (LLZTO) electrolyte and Li anode interface. The Ni-Al@LDH interlayer can significantly reduce the interfacial resistance as well as give excellent cycling performance both in a symmetric Li//Li cell and solid full lithium metal batteries.

Lithium-ion capacitors (LICs) have become one of the most popular energy storage devices because of the combination of high energy densities and power densities. However, the kinetic imbalance of anode and cathode restricts the specific capacities and voltage windows of LICs. Herein, an in-situ nitrogen-doped activated porous carbon (ANMPC) material with high specific surface area (1894.9 m2/g) is proposed to act as both cathode and anode for the preparation of the 4.5 V “all carbon” LICs. The hierarchically porous ANMPC obtained by KOH activation and carbonization of polypyrrole (PPy) has plenty of mesopores created by surfactant (added during the PPy process) as well as micropores generated by KOH activation, thus can provide abundant active sites for ion intercalation and large area for electrostatic adsorption simultaneously, satisfying the critical requirements of high-performance anode and cathode, respectively. After coupling the pre-lithiated ANMPC anode and fresh ANMPC cathode, the complete LIC device delivers large energy density of 167.5 Wh/kg at a power density of 269.0 W/kg, and still remains 88.9 Wh/kg at an ultrahigh power density of 13,198.5 W/kg, exhibiting enormous potential for applications in high performance lithium-ion capacitors.

Rechargeable Li-S batteries (LSBs) have aroused wide research interest due to their high energy density, yet still have many intractable challenges such as the sluggish sulfur electrochemistry, polysulfide shuttling, as well as hazardous Li corrosion/dendrites issues to be addressed. Here, we have simultaneously addressed these chal-lenges by developing a multifunctional PP separator covered by functional layers to regulate the interfacial electrochemistry in LSBs. The functional layer consisting of VS4 and tannin acid can synergistically work as redox mediators to catalyze the sulfur conversion and a buffer layer to regulate Li ions stripping/deposition behaviors. The LSBs with the as-designed multifunctional separator can deliver a considerable capacity of more than 3 mA h cm(-2) after 400 cycles, realize a stable cycling performance for 1200 cycles, and show excellent thermal tolerance even at a high temperature of 130 ?. By combining with the feasible manufacturing process, this separator engineering strategy bridges the electrode reactions initially and demonstrates safe LSBs for practical application.

Challenges remain for the preparation of high-performance rechargeable Zinc-air batteries (ZABs). Herein, we propose a bifunctional on Fe- and N-modified carbon nanofibers. The NiFe LDH@Fe-N-CNFs with a cross-linked network nanostructure possess abundant Fe-N-C reactive locations in Fe/N-codoped carbon nanofibers and ultrathin NiFe LDH nanosheets, which could greatly enhance ORR/OER activities. Importantly, the assembled ZABs triggered by the NiFe LDH@Fe-N-CNFs electrocatalyst exhibits a high capacity of 695.2 mA h g-1. An energy density of 838.6 Wh kgZn-1 and an outstanding stability of 184 h at 10 mA cm-2 are demonstrated. The superior performance of NiFe LDH@Fe-N-CNFs bifunctional electrocatalysts benefits from the synergy between Fe/N-modified carbon nanofibers and ultrathin NiFe LDH nanosheets with respective ORR and OER active sites. This work affords a rational design principle and strategy to design the bifunctional electrocatalyst.

The development of active, robust, and nonprecious electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is essential to improve the performance of Zn-air batteries (ZABs). Here, we present the FeCo2O4@ FeCo2S4 heterostructure in situ decorated on Ni foam as bifunctional electrocatalysts to trigger ORR and OER. Owing to the large electrochemical active surface area and synergistic effects at interfaces, the FeCo2O4@FeCo2S4/NF exhibits an OER overpotential of 283 mV at 10 mA cm-2, excellent robustness with negligible variation during continuous linear sweep voltammetry cycles, and an onset potential (Eonset) of 0.89 V (vs RHE) for ORR. Furthermore, the FeCo2O4@FeCo2S4/NF-triggered ZAB achieves a high power density of 189.75 mW cm-2 at 10 mA cm-2. In particular, the rechargeable ZAB with FeCo2O4@FeCo2S4/NF displays a small charge-discharge voltage gap and good cycle performance of up to 227 h at 10 mA cm-2.

Solid-state lithium–metal batteries (SSLMBs) with ceramic Li[Formula: see text]La3Zr[Formula: see text]Ta[Formula: see text]O[Formula: see text] (LLZTO) electrolytes are widely deemed to be a viable candidate for high-energy storage devices with attractive safety. However, inadequate contact, dramatical volume variation and dendrite growth severally impede their practical applications. Herein, a composite Li metal anode consisting of LiF and CaLi2 alloy is constructed by in-situ alloying reaction of Li and minute amount of CaF2. The as-formed CaLi2 alloy and LiF in the composite Li metal anode not only improve the wettability of molten lithium to LLZTO by decreasing the surface tension, but also achieve the intimate contact and avoid anode volume collapse. The interfacial resistance is successfully decreased from 405.9 to 12.9 [Formula: see text] cm2 by adopting the composite Li as electrodes. The symmetric cells can cycle at 0.1 mA cm[Formula: see text] for 1000 h, and cycle at 0.2 mA cm[Formula: see text] for 580 h. In addition, SSLMB by using LiFePO4 (LFP) as the cathode exhibits a capacity retention of 70.9% after 125 cycles at 0.3 C as well as good rate performance. This work puts forward a rational and economic strategy to pave the path for the advance of SSLMBs.

Rational design of highly efficient, robust and nonprecious electrocatalysts for the oxygen reduction reaction（ORR）, oxygen evolution reaction（OER） and hydrogen evolution reaction（HER） is highly demanded and challenging. Here, heterostructural Co 3 O 4 @Ni 2 P arrays with numerous reaction sites, unique interfacial electronic structure and fast charge transfer kinetics are developed as electrocatalysts for rechargeable Zn-air batteries and overall water splitting. Both density functional theory calculation and X-ray absorption fine structure analysis manifest that the synergistic structural and abundant electronic modulations interfaces are formed, thus simultaneously promoting the electrocatalytic kinetics, activities and stabilities. Specifically, it can achieve an ultralow overpotential of 270 m V and 28 m V at 10 m A cm -2 for OER and HER, respectively. The water electrolyzer delivers a current density of 10 m A cm -2 at 1.563 V;furthermore, rechargeable Zn-air batteries triggered by this heterostructure can achieve excellent cyclic stability of 177 h（2 h per cycle） at 10 m A cm -2 ; both devices are superior to the Pt/C + Ir/C. This work not only designs an efficient trifunctional electrocatalyst but also paves an avenue to understand the heterostructure engineering for catalysts development and disclose the underlying relationship of interfacial electronic structures and catalytic properties.

All-vanadium redox flow batteries (VRFBs), with good operation flexibility and scalability, have been regarded as one of the most competitive substitutes for large-scale energy storage. However, because of the low electrochemical activities of traditional electrodes such as carbon felt and graphite felt, they will impede the interfacial charge transfer processes and decrease the efficiencies of VRFBs. In this work, Co-MOF (ZIF-67) was prepared as a precursor, and a cobalt mixed nitrogen 3D carbon nanostructure and carbon felt (Co-CN@CF) was prepared by chemical reaction and used in VRFBs as electrodes. With the unique structure and high efficiency catalyst on the carbon felt, the Co-CN@CF exhibited excellent electrochemical activity toward the VO2+/VO2+ redox couple in the VRFB, with an average cell voltage efficiency (VE) of 86% and an energy efficiency (EE) of 82% at 80 mA cm−2, which was increased by more than 10% compared with the traditional carbon felt. VRFBs with a Co-CN@CF electrode also showed much better long-term stability (over 1000 cycles) compared with the battery with a pristine CF electrode.

Solid-state lithium metal batteries (SSLMBs) promise high energy density and high safety by employing high-capacity Li metal anode and solid-state electrolytes. However, the construction of the composite Li metal electrode is a neglected but important subject when the extensive research focuses on the interface between the solid electrolyte Li6.4 La3 Zr1.4 Ta0.6 O12 and Li metal anode. Here, an electronic-ionic conducting composite Li metal anode consisting of Li-Al alloy and LiF is constructed to achieve the stable electronic-ionic transport channel and the intimate interface contact, which can realize the uniform Li deposition and the efficiency utilization of lithium in composite Li metal electrode. Therefore, the symmetric battery with composite Li metal electrode exhibits the high critical current density with 1.2 mA cm-2 and stable cycle for 1500 h at 0.3 mA cm-2 , 25 °C. Moreover, the SSLMBs matched with LiFePO4 and LiNi0.8 Co0.1 Mn0.1 O2 achieve the outstanding electrochemical performance, verifying the feasibility of composite Li metal electrode in various SSLMBs systems.

Solid-state lithium-metal batteries (SSLMBs) using garnet Li6.4La3Zr1.4Ta0.6O12 (LLZTO) as the solid electrolyte are expected to conquer the safety concerns of high energy Li batteries with organic liquid electrolytes owing to its nonflammable nature and good mechanical strength. However, the poor interfacial contact between the Li anode and LLZTO greatly restrains the practical applications of the electrolyte, because large polarization, dendritic Li formation and penetration can occur at the interfaces. Here, an effective method is proposed to improve the wettability of the LLZTO toward lithium and reduce the interfacial resistance by engineering universal lithiophilic interfacial layers. Thanks to the in-situ formed lithiophilic and ionic conductive Co/Li2O interlayers, the symmetric Li/CoO-LLZTO/Li batteries present much smaller overpotential, ultra-low areal specific resistance (ASR, 12.3 Ω cm2), high critical current density (CCD, 1.1 mA cm-2), and outstanding cycling performance (1696 h at a current density of 0.3 mA cm-2) at 25 °C. Besides, the solid-state Li/CoO-LLZTO/LFP cells deliver an excellent electrochemical performance with a high coulombic efficiency of ~100% and a long cycling time over 185 times. Surprisingly, the high-voltage (4.6 V) solid state Li/CoO-LLZTO/Li1.4Mn0.6Ni0.2Co0.2O2.4 (LMNC622) batteries can also realize an ultra-high specific capacity (232.5 mAh g-1) under 0.1 C at 25 °C. This work paves an effective way for practical applications of the dendrite-free SSLMBs.

A pore enriched CoNiO2@reduced graphene oxide hollow fiber (CoNiO2@rGOF) is constructed as battery-type materials via the combination of wet-spinning and hydrothermal approaches. Thanks to the in-situ nucleation and growth of the porous and ultrathin CoNiO2 nanosheets, as well as the good conductive and hollow structure of rGOF, the as-obtained CoNiO2@rGOF cathode delivers specific capacities of 645.8 and 460.0 C g(-1) at 2 and 50 A g(-1), respectively, displaying an extraordinary rate capability. Significantly, it can be cycled more than 50,00 0 times with an amazing capacity increase of 42.9%. The CoNiO2@rGOF//rGOF supercapacitor (SC)-battery hybrid device achieves an energy density of 43.99 Wh kg(-1) at a power density of 1.70 kW kg(-1); even at a high power density of 21.61 kW kg(-1), the energy density could stay as high as 38.41 Wh kg(-1). Importantly, a 2.0 V light emitting diode (LED) could be lit up for more than half an hour by two hybrid devices in series. This work describes here provides a versatile pathway to construct graphene hollow fibers-based hybrid materials for various applications. (C) 2020 Elsevier Ltd. All rights reserved.

As a typical metal selenide, CoSe is a kind of foreground anode material for lithium-ion batteries (LIBs) because of its two-dimensional layer structure, good electrical conductivity, and high theoretical capacity. In this work, the original CoSe/N-doped carbon (CoSe/NC) composites were synthesized using ZIF-67 as a precursor, in which the CoSe nanoparticles are encapsulated in NC nanolayers and they are connected through C–Se bonds. The coating structure and strong chemical coupling make the NC nanolayers could better effectively enhance the lithium storage properties of CoSe/NC composites. As a consequence, the CoSe/NC composites deliver a reversible capacity of 310.11 mAh g −1 after 500 cycles at 1.0 A g −1 . Besides, the CoSe/NC composites show a distinct incremental behavior of capacity.

As a member of transition metal chalcogenides (TMCs), alpha-MnSe is a prospective anode material for lithium-ion batteries (LIBs). However, there are few studies about its application in LIBs. In this work, two unique structures of alpha-MnSe/carbon nanofiber (alpha-MnSe/CNF) and alpha-MnSe/C microspheres were prepared using manganese-based metal organic framework (Mn-BTC) as forerunner that reacted with Se powder at elevated temperature. The MnSe nanoparticles of in-situ formation are uniformly anchored on CNF originated from the organic ligands of Mn-BTC. As a result, alpha-MnSe/CNF and alpha-MnSe/C microspheres exhibit excellent lithium storage performance. The alpha-MnSe/CNF delivers specific capacities of 845.54 mAh g(-1) after 100 cycles at 0.1 A g(-1). Even at 1.0 A g(-1) it still remains a reversible capacity of 544.6 mAh g(-1) after 500 cycles. As for alpha-MnSe/C microspheres, the corresponding capacities are 784.82 and 516.86 mAh g(-1), respectively.