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Practical application of lithium metal anodes in high-energy rechargeable batteries is impeded by the issue of Li dendrite growth. Herein, an exceptional hydrophobic MAF-6 material is utilized to modify polypropylene (PP) separator to yield a superorganophilic MAF-6/PP composite separator. Owing to a combination of superorganophilicity with three-dimensional ordered porosity, the MAF-6/PP achieves a Li ion transference number of 0.78. Homogeneous and dense Li plating behaviors are present in cells with MAF-6/PP which can afford uniform Li ion flux. The MAF-6/PP enables Li|Cu cells to run steadily for over 350 cycles at 0.5 mA cm−2-1 mAh cm−2 with an average coulombic efficiency (CE) of 98.8%, symmetric Li|Li cells to work stably for 2200 h without short-circuit at 0.5 mA cm−2-1 mAh cm−2, and Li|LiFePO4 cells to retain a reversible capacity of 102.4 mAh g−1 after 1500 cycles at 1C with a capacity retention of 73.2% and a CE of 99.9%.

Low-cost, high-activity, non-precious metal electrocatalysts are needed to enhance the bifunctional oxygen activities of rechargeable Zn-Air batteries. In this study, a Fe-enriched FeNi3 inter-metallic nanoparticle/nitrogen-doped carbon (Fe-enriched-FeNi3/NC) electrocatalyst was designed and prepared using a facile method based on plasma engineering. The excess Fe-ions in the Fe-enriched FeNi3 nanoparticles led to a high degree of lattice distortion that produced abundant oxygen-active sites. The electrocatalyst exhibited excellent oxygen evolution reaction (OER) activity as well as favorable oxygen reduction reaction (ORR) activity in an alkaline electrolyte. In addition, the electrocatalyst revealed a lower potential difference (ΔE = 0.80 V vs. RHE) in a bifunctional oxygen reaction compared to that of the benchmark 20 wt% Pt/C + Ir/C (ΔE = 0.84 V vs. RHE), and most of the reported FeNi3 alloy-doped carbon catalysts. Based on DFT calculations, the lattice distortion in Fe-enriched-FeNi3/NC promoted a higher density of active electrons around the Fermi level. Owing to its great bifunctional oxygen activities, Fe-enriched FeNi3/NC was applied as an ORR/OER catalyst in the air cathode in a homemade zinc-air battery and exhibited an excellent discharge–charge voltage gap (0.89 V), peak power density (89 mW/cm2), and high specific capacity of 734 mAh/g at 20 mA/cm2, which outperformed the benchmark 20 wt% Pt/C + Ir/C electrocatalyst. In summary, this research provides a novel strategy to enhance the OER/ORR activities of transition metal-based alloys through lattice distortion defects. In addition, it provides a new pathway for achieving noble metal-free air cathode materials for the next generation Zn-air battery.

Construction of three-dimensional (3D) composite lithium metal anodes (LMAs) based on Li melt-infusion into a 3D porous scaffold has been demonstrated to be effective for solving the issue of the considerable relative volume change of LMAs during Li plating/stripping. However, little attention has been paid to controllable regulation of the structure and interface of 3D composite LMAs. In this study, 3D composite LMAs, namely Li–AuLi3@CF electrodes, are firstly fabricated by infusion of molten Li into carbon fiber (CF) paper modified with nanoporous gold (NPG) which is converted to AuLi3 after infusion. We herein demonstrate a synergistic structure and interface engineering strategy realized by a simple and effective pre-stripping protocol to initially expose a portion of the 3D AuLi3@CF scaffold to create “PS-Li-AuLi3@CF” electrodes, which greatly boosted the electrochemical performance. Symmetrical Li|Li cells with PS-Li-AuLi3@CF electrodes show an overpotential of 111 ​mV after cycling at a current density of 0.5 ​mA ​cm−2 for 1800 ​h. Additionally, Li|LiFePO4 (LFP) and Li|sulfurized polyacrylonitrile (SPAN) full cells with PS-Li-AuLi3@CF electrodes exhibit a high capacity retention of 96.1% with a Coulombic efficiency (CE) of 99.2% after 1000 cycles at 5C, and a capacity retention of 70.6% with a CE of 99.8% after 1000 cycles at 2C, respectively. This work provides a simple and highly effective method for engineering the structure and interface of 3D composite LMAs to boost their electrochemical performance for high-energy-density rechargeable lithium metal batteries (LMBs).

The short life span of lithium metal anodes (LMAs) due to dendrite growth and low coulombic efficiency (CE) has been regarded as the bottleneck in developing next-generation high-energy-density lithium metal based secondary batteries. Employing three-dimensional (3D) current collectors is one approach to reduce the effective current density and delay dendrite growth. Commercial Ni foam, in spite of its high electronic conductivity and 3D topology, has not been considered for this application due to its low specific surface area and lithiophobic nature. In this study, we develop a surface engineering strategy to uniformly coat lithiophilic AuLi3 particles on Ni foam skeletons through lithiation of electrodeposited gold nanoparticles. In comparison with the bare Ni foam, the AuLi3@Ni foam is more lithiophilic, significantly lowering the nucleation energy barrier and enhancing the uniformity for Li deposition. Such a structure results in effective suppression of Li dendrite growth in the void space of the foam. As a result, the AuLi3@Ni foam current collector based LMAs can run for 740 h without cell failure in a symmetric cell. Furthermore, the Li-AuLi3@Ni foam|LiFePO4 full cell shows an excellent capacity retention of 43.8% with a high CE of 99.2% at 1C for 500 cycles. This work further illustrates the critical importance of surface lithiophilicity in guiding lithium cycling and suggests engineering the skeleton surface of commercial metal foam current collectors is important to improve 3D structured LMAs.

Cu2P7-black P-MWCNT (CuP5/MWCNT) is prepared by a facile mechanical milling method. When used as anodes for Li/Na-ion batteries, the composite delivers high comprehensive performances: initial Coulombic efficiency up to 90/84%, 1455/1170 mA h g−1 after 200 cycles, and 960/580 mA h g−1 at 5 A g−1 for Li/Na-ion batteries, respectively. The performances can be attributed to the hybridized strategy of two-dimension layered structure of Cu2P7, black P, and one-dimension multiwall carbon nanotubes. The former offers a fast transport channel for Li/Na-ions and the latter provides for fast transport of electrons and accommodates the volume variation during cycling. In addition, the synergistic effect among different phases also leads to enhanced performance. The integrated strategy of one-dimensional and two-dimensional advantages can excite more research interest in the energy-storage field.

Transition metal sulfides such as Ni–Co sulfides are promising electrode materials for supercapacitors owing to their advantageous electrical conductivity. Current approaches for the synthesis of Ni–Co sulfides normally involve wet chemical sulfurization. In this work, we demonstrate a facile method for synthesizing CoxNi1-xS2 (0

Phosphides are promising anode candidates profiting from their relatively smaller voltage hysteresis which thus are promising to be high energy efficiency and power capabilities for secondary batteries, compared with the corresponding fluorides, oxides and sulfides. Herein we for the first time synthesized ternary Cu 2 P 7 /CuP 2 /graphite composite by a facile ball milling method. When initiated as anodes for Li-ion batteries, the as-synthesized ternary composite provides 1415 mA h g −1 after 100 cycles and 684 mA h g −1 at a high current density of 10 A g −1 . When initiated as anodes for Na-ion batteries, the as-synthesized ternary composite provides 1254 mA h g −1 after 100 cycles and 200 mA h g −1 at a high current density of 5 A g −1 . These electrochemical performances are comparable or even surpass the P/C, CuP 2 /C and other transition metal phosphides reported before. The enhanced performances can be attributed to the high P concentration, layered structure and small band gap of the Cu 2 P 7 phase and the heterointerface between these phases, which not only assists electron and Li-ion transportation and but also creates more active sites endowed by interfacial coupling and positive electrochemical synergistic effect. The multiphase design strategy can further excite more research interest in the energy-storage field.

Various P-Ge compounds including GeP5 and GeP3 can be easily synthesized by a direct ball milling method while GeP can not. Herein, we successfully synthesize binary-phase Ge2P3 composite which derived from layered GeP and black P. When applied as anodes for Li-ion batteries, the as-synthesized binary-phase composite delivers a large reversible capacity of 1605 mA h g−1 with a high initial Coulombic efficiency of 89%, retains 1380 mA h g−1 after 100 cycles and even achieves 920 mA h g−1 at a current density of at 5 A g−1. Also, for sodium-storage it shows a reversible capacity of 970 mA h g−1 with an initial Coulombic efficiency of 88% and retains 890 mA h g−1 after 100 cycles. The performance can be attributed to the following merits: the binary Li/Na-storage components host more Li/Na ions, the layered structure favors Li/Na-ion transportation and the abundant heterointerfaces increase the amount of active sites.

Recently, rechargeable Zn-ion batteries (ZIBs) have attracted incremental attention as prospective energy storage devices for grid-scale applications and flexible devices, due to their low cost, environmental benignity, high safety and unique properties of the Zn metal. However, the sustained development of high-performance ZIBs is hindered by the limited availability of cathode materials. Here, for the first time, we demonstrate MoS2 with expanded inter-layer spacing (E-MoS2) can be a promising cathode candidate for rechargeable and flexible ZIBs. By X-ray diffraction (XRD) and Raman studies, a reversible Zn2+ ion intercalation/deintercalation mechanism was revealed. The E-MoS2 electrode delivers a specific capacity of 202.6 mA h g−1 at 0.1 A g−1, a desirable energy density of 148.2 Wh kg−1 and good cycle stability with a capacity retention ratio of 98.6% over 600 cycles. By using the newly-developed starch/ polyacrylamide (PAM) based polymer electrolyte with high zinc ion conductivity, a quasi-solid Zn/E-MoS2 battery was developed, which exhibits decent electrochemical performance even under various heavy deformations, holding great potential for applications in future flexible and wearable devices.

In this work, a unique artificial interface combing characteristics of both high ionic and electronic conductivities has been successfully constructed at the surface of Ni-rich LiNi0·8Co0·1Mn0·1O2 (NCM811). The ionic conductor layer is fabricated through reacting H3PO4 with the lithium residuals on the surface of NCM811 to form Li3PO4. The interface with high electronic conductivity is constructed by attaching graphene fragments to the NCM811 spherical particles. Due to the synergistic effect of the Li3PO4 coating layer and the graphene network, the modified sample (GN-LPO-NCM811) exhibits high capacity retention of 94.3% after 150 cycles at 0.5C between 3.0 and 4.3 V, while the pristine material shows a much lower retention of only 88.1%. In addition, the GN-LPO-NCM811 also presents improved cycling stability at elevated temperature of 55 °C. Even at an extremely high rate of 10C, the GN-LPO-NCM811 still remains 70% of its original capacity, while the pristine NCM811 only delivers 50% of the capacity. The stable cycling performance of GN-LPO-NCM811 is demonstrated in a full cell with graphite anode at ambient temperatures. Importantly, the thermal stability of the modified samples is also greatly enhanced. This study provides an effective method to improve the electrochemical performance of LiNi0·8Co0·1Mn0·1O2.

Nanocomposites LiMnxFe1-xPO4/C (x = 1, 5/6, 2/3, 1/2) are synthesized by a sol-gel route combined with freeze drying. Fe2+ substituted samples coated by high-ordered carbon have the same olivine structure of LiMnPO4/C but reduced cell volumes. Fe2+ substituting greatly influences magnetic characteristics of LiMnPO4/C and slight amounts of Fe2P impurity in Fe2+ doped samples are verified by magnetic tests. Fe2+ substituted samples exhibit much better electrochemical properties. Among them, LiMn1/2Fe1/2PO4/C displays the best rate capacity and cyclic stability. Its initial discharge capacity reaches 140.1 mAh g−1 and remains at 132.5 mAh g−1 after 100 cycles at 2C, remarkably higher than those of LiMnPO4/C. The superior electrochemical performances are mainly attributed to small charge-transfer impedance, fast Li+ diffusion, residual carbon and existence of Fe2P with excellent electronic conductivity.

AP65 doped with different elements are rolled into the anode plates for Mg-air battery and higher-power seawater activated battery. The discharge and corrosion behaviour of their cross- section surfaces (CS) and rolling surfaces (RS) is systematically studied and the results show that the RS consisting of (0001) crystallographic planes have lower corrosion rates and inhibit the self- discharge at 180 mA cm−2, whereas the CS with ( 11 2 ¯ 0 ) and ( 10 1 ¯ 0 ) planes provide higher anodic efficiencies at 10 mA cm−2 and possess stronger discharge activity. Furthermore, the dissolution mechanisms of different surfaces are also elucidated based on microstructure characterization and electrochemical response.

Ni-rich layered oxide (LiNi0.8Co0.1Mn0.1O2) has become popular commercial cathode material for lithium ion batteries, due to its high working potential and high specific capacity. It is still a challenge, however, to maintain the structure and performance under extreme conditions, such as at high charging cutoff (≥4.5 V), high temperature (≥60 °C) and higher charge-discharge rate (≥3 C). Herein, Poly (pyrrole-co-citral nitrile) (PPC) optimized interfacial layer is designed and constructed on the surface of LiNi0.8Co0.1Mn0.1O2 by an in situ photopolymerization self-assembly technology. The sweater-like co-polymer coating provides an integral protection from side reaction, particle rupture and irreversible phase transition during cycling under the extreme conditions. Furthermore, the delocalized π bonds and cross-linked network structure of the co-polymer coating ensure the efficient and stable interface between electrolyte and electrode. This work offers a novel and useful strategy to enhance the electrochemical performance of Ni-rich cathode materials for high-energy lithium ion batteries at extreme conditions.

Rechargeable lithium oxygen batteries (LOBs) are one of the most promising energy storage systems by virtue of their high energy density and environmental amiability. However, the development of LOBs is still hindered by some critical issues. Herein, 3D hexapod-shaped Co-ZIFs-thiourea/dimethyl sulfoxide (H-Co-ZIFs-S) derived Co nanoparticles embedded into nitrogen and sulfur co-doped carbon (H-Co-NSC) are developed, and then low content of ruthenium nanoparticles are decorated on the surface to obtain Ru/H-Co-NSC as efficient catalyst for LOBs. The Ru/H-Co-NSC catalysts exhibits unique structure and catalytic properties, such as accommodating the insoluble discharge product Li2O2, promoting the transportation of ions/O2, enhancing the electronic conduction, demonstrating excellent OER/ORR kinetics as well. In addition, the Ru-decorated nanoparticles could effectively suppress some side-reactions caused by the exposed carbon of H-Co-NSC in LOBs. First-principles Density functional theory (DFT) calculations reveal the cooperative effect of multiple active sites in Ru/H-Co-NSC can effectively promote the ORR/OER kinetics in LOBs. Therefore, the LOBs with Ru/H-Co-NSC cathode provide a positive catalytic capacity with low overpotential, large specific capacities, long cycle life and superior reversibility. Our work may pave the way to design more advanced catalysts for metal-air batteries with superior electrochemical performance.

Constructing the M-N-C (M = Fe, Co, etc.) with meso- and macroporous structures is an effective strategy for designing the high-performance catalysts towards oxygen reduction reaction (ORR). However, these structures can hardly be achieved via the pyrolysis of classic metal-organic frameworks. Herein, we prepare the CoFe nanoparticles with surface oxides dispersed in Co/Fe-N-C support via carbonizing melamine and ethylenediaminetetraacetic acid chelated with metal ions. This hybrid exhibits high proportions of meso- and macropores along with excellent ORR catalytic activity, as evidenced by the half-wave potentials of 0.91 and 0.61 V (vs. RHE) in 0.1 M KOH and 3.5 wt% NaCl, respectively. The Al/Mg-air batteries with this catalyst exhibit superior performance to those employing Pt/C, primarily derived from the enlarged pore diameters and the exposed ORR active sites substantially enhancing the air-electrode performance. Our study provides an avenue to broaden the pore sizes of M-N-C for boosting its ORR catalytic activity.

LiNi0.5Mn1.5O4 is a promising cathode material for high power lithium ion batteries (LIBs) for electric vehicles (EVs) and hybrid electric vehicles (HEVs). For the first time we design a tri-functional coating to improve the cycling performance of LiNi0.5Mn1.5O4. With the designed BiPO4 coating, the capacity retentions of LiNi0.5Mn1.5O4 are largely improved from 84.3% to 93.6% at 0.5 C after 50 cycles and from 80.6% to 96.2% at 10 C after 100 cycles. The tri-functional coating reduces the charge transfer resistance of LiNi0.5Mn1.5O4 cathode and plays a critical role in enhancing the electrochemical performance and lifetime. This strategy provides a new way to modify electrode materials to elevate the performance of LIBs.

High-performance energy storage devices are in urgent need due to the fast development of wearable electronics, while the challenge of achieving outstanding flexibility has not been properly addressed yet, let alone the safety, another critical issue determines their practicability. Herein, we report a quasi-solid-state aqueous rechargeable lithium-ion battery (ARLIB) based on carbon cloth substrates and PVA-LiNO3 gel polymer electrolyte (GPE). Thanks to the protective PPy coating layer on LiV3O8 and the use of solid GPE, the as-assembled ARLIB exhibits a good cycling stability of 98.7% and 79.8% capacity retention after 100 and 500 cycles, respectively. It also demonstrates exceptional flexibility to sustain various deformations including bending, squeezing, twisting and folding because of its solid-state design. Moreover, the ARLIB can be tailored into any desired shapes, and even be punched penetrative holes, exhibiting excellent safety. Thus, the creation of numerous tiny through-holes across the whole ARLIB body is testified feasible, and a designed breathability catering to the demand of comfortability in wearable devices is subsequently realized. Obviously, our study offers a promising strategy to construct flexible energy storage device with outstanding stability, flexibility, safety and breathability towards various wearable electronics.

Cathode materials LiMn 0.5 Fe 0.5 PO 4 /C and LiMnPO 4 /C were synthesized by a high-energy ball-milling assisted sol-gel method. The LiMn 0.5 Fe 0.5 PO 4 consists of nanorods and nanoparticles homogeneously wrapped with highly ordering carbon. The increased Neel-temperature and decreased effective magnetic moment of LiMn 0.5 Fe 0.5 PO 4 /C revealed the microstructure differences from LiMnPO 4 /C. Meanwhile, tiny amount of ferromagnetic impurities is detected in LiMn 0.5 Fe 0.5 PO 4 /C by magnetic tests. The synergetic effects of Fe substitution and carbon coating remarkably improve rate capacity and cyclic stability of LiMn 0.5 Fe 0.5 PO 4 /C. This solid solution delivers initial discharge capacities of 128.6 mAh g −1 and 116.3 mAh g −1 and capacity retentions of 93.5% and 90.3% after 100 cycles at 1C and 2C respectively, significantly better than LiMnPO 4 /C.

Well-aligned Zn 3 P 2 nanowires-assembly bundles/Ti foil integrated anodes were for the first time successfully synthesized by a facile chemical vapor deposition. When directly applied as anodes for lithium/sodium ion batteries, they show excellent lithium/sodium storage performance especially in high-rate capability. Specifically, applied as anode material for lithium ion batteries, it showed 1100 mA h g −1 after 100 cycles and an ultrahigh rate performance with 300 mA h g −1 even at 40 A g −1 ; as anode material for sodium ion batteries, it was, for the first time, investigated and delivered a high initial specific capacity of 1120 mA h g −1 , and excellent rate capability with 280 mA h g −1 at 5 A g −1 , demonstrating that Zn 3 P 2 nanowires-assembly bundles/Ti foil integrated anodes are a promising anode candidate for lithium/sodium ion batteries. The Ex-situ XRD and HRTEM were for the first time, carried out to investigate the sodium storage mechanism of Zn 3 P 2 . Such superior lithium/sodium storage performances can be attributed to this well-aligned Zn 3 P 2 nanowires-assembly bundles structure, which not only mitigates the volume expansion of Zn 3 P 2 during cycling but also provides the direct electron transfer to ensure high-rate performances.

Fabricating the magnesium alloy with fine grains, low dislocation density, and weak grain orientation is of crucial importance to enhance its anode performance for primary aqueous battery. However, this structure mode can hardly be realized for bulk magnesium alloy via the conventional approaches such as plastic working. Herein, we construct an AZ31 magnesium alloy with ultrafine grains (667.28 ± 291.35 nm) by using the spark plasma sintering of the alloy powder that has been treated via high-energy ball milling. This alloy exhibits weak grain orientation and its dislocation density is not increased compared to the precursor alloy. Benefiting from the unique microstructure, the modified AZ31 displays significantly more active behaviour with enhanced capacity during the discharge of Mg-air battery, as compared with the precursor AZ31 that has the grain size of 472.89 ± 154.31 μm. Furthermore, the impact of ultrafine grains on the discharge behaviour is also analysed based on microstructure characterization and electrochemical response.

Biomass walnut shell was used to prepare activated carbon (AC) through a carbonization treatment and an activation procedure with potassium hydroxide (KOH). AC showed hierarchical pores: 0.6 nm micropores, 2.7 nm mesopores and macropores with average diameter of 50 nm, providing a large specific surface area of 2318 m 2 g −1 . This highly porous AC was tested as a host material to encapsulate sulfur via a vapor phase infusion process. The developed AC-S electrode showed a high initial specific capacity of 1350 mAh g −1 and good capacity retention over 100 cycles at 0.1 C for lithium–sulfur battery.

Nano-sized 5LiFePO 4 ·Li 3 V 2 (PO 4 ) 3 /C composite was synthesized via improved carbothermal reduction combined high-energy ball milling. XRD results reveal that the composite is composed of olivine LiFePO 4 and monoclinic Li 3 V 2 (PO 4 ) 3 phases. Meanwhile small amounts of V 3+ and Fe 2+ as dopants entered into the lattices of LiFePO 4 and Li 3 V 2 (PO 4 ) 3 , respectively. Trace amounts of Fe 2 O 3 in LiFePO 4 /C and Fe 2 P in 5LiFePO 4 ·Li 3 V 2 (PO 4 ) 3 /C were identified and quantified by magnetic tests. And magnetic parameters of 5LiFePO 4 ·Li 3 V 2 (PO 4 ) 3 /C are significantly different from LiFePO 4 /C. The 5LiFePO 4 ·Li 3 V 2 (PO 4 ) 3 /C presents initial discharge specific capacities of 145.2 mAh g −1 and 133.9 mAh g −1 and no capacity attenuations after 50 cycles can be observed at 2C and 5C respectively. Compared with LiFePO 4 /C, its rate capability and cyclic stability are both enhanced greatly. The mutual doping, synergistical effect of LiFePO 4 and Li 3 V 2 (PO 4 ) 3 and contribution of Fe 2 P are mainly responsible for the excellent electrochemical performances.

The gel formation and transformation to crystal of moxidectin (Form I) during the anti-solvent crystallization was studied in this paper. Several characterization techniques were used to monitor and identify this process, including online and offline instruments, such as X-ray powder diffraction (PXRD), polarizing microscope(POM), differential scanning calorimetry (DSC), focused beam reflectance measurement (FBRM) and On-line Forier transform infrared (FTIR). The results demonstrated that tiny crystal nucleus could be found after certain amount water was added into the solution, and then the tiny crystal nucleuses served as gelators and induced the system to form gel through the hydrogen bonds between moxidectin and water molecules. Finally, the gel would transform to form I due to the instability of gel.

Lithium–sulfur batteries with a high energy density are promising energy storage devices. The realization of lithium–sulfur batteries is mainly hindered by the dissolution of the intermediate polysulfides. In the present work, a new physical and chemical entrapment method of the polysulfides has been proposed, which used CMK-3 as the carbon scaffolds and a MnO 2 coating layer for chemisorption. Such a bi-functional framework provides efficient trapping for the polysulfides, achieving a reversible capacity of 600 mAh g −1 after 100 cycles at 0.1 C with a 73.4 wt% sulfur loading in the composite.

Using electrical vehicles instead of traditional ones is very important for reducing fossil oil consumption and carbon emissions. Spinel LiNi0.5Mn1.5O4 is considered as a promising cathode material for advanced lithium ion batteries owing to its high power density. Nevertheless, it suffers badly from the interfacial reactions with the electrolyte at high operation potential, which degrades its electrochemical performance. The strategy of the present study is to prevent direct contact between LiNi0.5Mn1.5O4 and the electrolyte by using a surface coating in order to reduce solid electrolyte interfacial reactions and consequently enhance its cycling performance. The experimental results indicated that as-prepared LiNi0.5Mn1.5O4 sintered at 900 °C possessed the highest initial specific capacity of 132.4 mA h·g−1 at 0.2 C rate, with 81.0% initial capacity retention after 50 cycles. Coating AlF3 on the particle surfaces of LiNi0.5Mn1.5O4 using a modified solid-state method can improve its electrochemical properties by enhancing its initial specific capacity from 104.6 to 109.1 mA h·g−1 and increasing its capacity retention from 80.6 to 92.1% at the 10 C rate after 100 cycles.

High specific-capacity pseudocapacitive transition-metal-hydroxide (TMH) materials are desirable for future high performance transparent supercapacitors, but have been rarely reported previously. The successful synthesis of TMH materials with desired nanostructures is a key factor for their transparency. Here, Ni(OH)2 nanosheet transparent film (NNS-TF) was developed simply through a gas-liquid diffusion method. The nanostructures were enwrapped in graphene shells (NNS@Gr-TF) for using as transparent electrodes. The unique encapsulation structures build up rapid three-dimensional electron and ion transport pathways together with the underlying ITO layer. The specific areal capacitance (18.9 mF/cm2 at 0.1 mA/cm2) was greatly improved, at least a thousand times higher than the reported value for transparent devices based on planer CVD graphene, and ten times as that for 3D micro-structured graphene membrane.

The δ-MnO2 nanowires are fabricated and chemically bonded with the carbon black that has appropriate amounts of oxygen containing functional groups. These short δ-MnO2 nanowires are (006) crystal plane-dominated and the hybrid (δ-MnO2 nanowires/carbon black) exhibits enhanced electrocatalytic activity towards oxygen reduction reaction (ORR). The half-wave potential (0.82 V (vs. RHE)) and limiting-current density (5.47 mA cm−2) of the hybrid in alkaline medium are close to those of 20 wt% Pt/C, respectively. The hybrid is used as cathodic catalyst in a Zn-air battery cell, which displays a peak power density of 138.0 mW cm−2, comparable to that using Pt/C catalyst (142.8 mW cm−2). This excellent catalytic performance is attributed to the unique microstructure of the hybrid that accelerates the kinetics of ORR. Furthermore, the ORR catalytic mechanism is also systematically analysed based on the microstructural characterization and electrochemical response.

In order to improve the performance of Ni-rich cathode materials for lithium-ion batteries at high cut-off voltage, a highly effective TiO2 nano-coating is constructed on the surface of LiNi0.8Co0.1Mn0.1O2 by precisely controlling the hydrolytic dynamics of Ti4+, and the effect of this coating layer is systematically studied, especially at high upper cut-off voltage. The continuous TiO2 nano-coating layer provides a complete protection for LiNi0.8Co0.1Mn0.1O2 particles and enhances the reversibility of the phase transition between hexagonal and hexagonal (H2→H3) during cycling, which guarantees an excellent cycling stability under high upper cut-off voltage up to 4.5 V. Electrochemical impedance spectroscopy results confirm a stable interface between electrolyte and electrode and the fast kinetics at the surface of the modified sample. High Resolution Transmission Electron Microscopy (HR-TEM) measurement for the cycled electrodes further verifies the slight structure decay of the coated sample comparing with the pristine one. Thus, the modified sample presents excellent cycling stability with capacity retention of 72.2% after 500 cycles and 63.4% after 1000 cycles with the upper cut-off voltage of 4.5 V and 4.3 V, respectively. This work provides a universal method to prepare conformal TiO2 nano-coating and also offer guidance to properly evaluate the function of a coating.

A series of lithium borate added electrolyte compounds, xLi3BO3-(1−x)Li3.5Si0.5P0.5O4 (0 ≤ x ≤ 0.2), are synthesized and characterized. This so-called LISICON electrolyte system is analyzed by using X-ray diffraction (XRD), scanning electron microscopy (SEM), solid state nuclear magnetic resonance (ss-NMR), electrochemical impedance spectra (EIS), and direct current (DC) polarization methods. From 11B MAS NMR spectra, it is demonstrated that a small fraction of boron exists in the form of BO4, while its majority settles at grain boundaries in the form of BO3, indicating that lithium borate glasses play a role as sintering assistant. This prominently increases the relative density of samples, and is beneficial to the ionic conductivity. Further results show that the electrical conduction of lithium borate added LISICONs is dominated by Li+ ions, with a transference number of tLi+ ≥ 0.996 and a corresponding ionic conductivity of about 6.5 × 10−6 S cm−1 at room temperature, almost two times that of pristine Li3.5Si0.5P0.5O4.

Flexible lithium sulfur batteries are promising power sources for the next generation wearable electronics, due to their high energy density and low cost. Here, we demonstrate a metal current collector-free, binder-free, flexible sulfurized polyacrylonitrile film electrode with hollow tubular nanofibers (H-SPAN), which is fabricated via coaxial electrospinning and a simple heat treatment. The all-fibrous films H-SPAN not only provides three-dimensional continuous electron and ion transport paths, but also suppresses the shuttle effect, contributing to better redox kinetics, cycling performance, and flexibility. The H-SPAN film electrode delivers a high specific lithium storage capacity of 1250 mAh g−1sulfur or 514.75 mAh g−1electrode at 0.1C with stable cycling over 300 cycles. Additionally, when H-SPAN is applied as a cathode for room temperature Na–S batteries, it also exhibits superb capacity and cycling stability (717 mAh g−1sulfur or 295.2 mAh g−1electrode at 0.1C after 200 cycles). The working mechanism of H-SPAN is well elucidated by ex situ Raman spectroscopy and ex situ X-ray Photoelectron Spectroscopy (XPS). The excellent flexibility of the H-SPAN film electrode lends itself well to potential applications in wearable electronic devices.

Facile green and scalable synthesis of low-cost nonprecious metal electrocatalysts which favor a four-electron pathway for the oxygen reduction reaction (ORR) are in great need for high-performance metal-air batteries. Herein, an ultrasonication-assisted synthesis method of preparing MnO2 nanosheets anchored on carbon black (MnO2/Super P Li) ORR catalyst is proposed. Three kinds of MnO2 nanostructures can be controlled and conformably deposited on Super P Li backbone. The MnO2/Super P Li composites facilitates a four-electron ORR process and demonstrates superior stability than the benchmark catalyst Pt/C in alkaline solutions. Moreover, the Zn-air battery using one of the MnO2/Super P Li catalysts displays a specific capacity of 705mA h g−1 and the voltage platform is almost unchanged after discharge for 180 h. The high ORR activity of the hybrid catalyst can be attributed to the MnO2 nanosheets uniformly grown on the Super P Li three dimensional (3D) framework and the appropriate Mn(Ⅲ)/Mn(Ⅳ) of the MnO2/Super P Li composite which can magically catalyze the reduction of hydrogen peroxide. Due to the high ORR activity and the superior stability, low cost MnO2/Super P Li catalysts lends itself well to potential applications in renewable energy conversion devices.

Graphene/nickel oxide composite (G/NiO) was synthesized through a facile hydrothermal method and subsequently microwave thermal treatment by using alcohols-reduced graphene as substrate. The as-prepared G/NiO was characterized by X-ray diffraction, Raman spectra, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscope. The results indicate that the graphene oxide has been successfully reduced to graphene, and NiO nanoparticles are homogeneous anchored on the surface of graphene, forming a globule-on-sheet structure. The loading content of NiO nanoparticles anchoring on the surface of graphene nanosheets can be controlled by adjusting the hydrothermal temperature. The G/NiO displays superior electrochemical performance with a specific capacitance of 530 F g −1 at 1 A g −1 in 2 M of NaOH. After 5000 cycles, the supercapacitor still maintains a specific capacitance of 490 F g −1 (92% retention of the initial capacity), exhibiting excellent cycling stability.

A three-dimensional lithium iron phosphate (LiFePO4)/carbon nanotubes (CNTs)/graphene composite was successfully synthesized via solid-state reaction. The LiFePO4/carbon nanotubes/graphene (LFP–CNT–G) composite used as Li-ions battery cathode material exhibits superior high-rate capability and favorable charge–discharge cycle performance under relative high current density compared with that of LiFePO4/carbon nanotubes (LFP–CNT) composite and LiFePO4/graphene (LFP–G) composite. Graphene nanosheets and CNTs construct 3D conducting networks are favor for faster electron transfer, higher Li-ions diffusion coefficient and lower resistance during the Li-ions reversible reaction. The synergistic effect of graphene nanosheets and CNTs improves the rate capability and cycling stability of LiFePO4-based cathodes. The LFP–CNT–G electrode shows reversible capacity of 168.9 mA h g−1 at 0.2 C and 115.8 mA h g−1 at 20 C. The electrochemical impedance spectroscopy demonstrate that the LFP–CNT–G electrode has the smallest charge-transfer resistance, indicating that the fast electron transfer from the electrolyte to the LFP–CNT–G active materials in the Li-ions intercalation/deintercalation reactions owing to the three-dimensional networks of graphene and carbon nanotubes.

Wrought Mg-Al-Pb-RE strips of different thicknesses are synthesized via extrusion and used as the anodes in Mg-air batteries. We find that, compared to other Mg-Al-Pb-RE samples, the 5 mm-thick strip exhibits greater stability and higher discharge voltage plateaus for long time (10 h). Its anodic efficiency at 10 mA cm −2 reaches 64.1%, which is even higher than pure magnesium and AZ31 magnesium alloy. The outstanding performance of the 5 mm-thick Mg-Al-Pb-RE anode strip is attributed to its unique microstructure favourable for anodic dissolution. Furthermore, the correlations between microstructure features and electrochemical performance for the wrought Mg-Al-Pb-RE strips are also systematically defined.

Metallic lithium (Li) has been acclaimed as the most promising anode materials for lithium batteries due to its ultrahigh theoretical capacity of 3860 mA h g−1. Its practical application is impeded, however, due to the notorious problems related to dendrite growth caused by its uneven current density distribution and high Li nucleation overpotential. Here, we report a three-dimensional (3D) lithiophobic phase (Cu) and lithiophilic phase (Zn or Sn) composite architecture realized through a facile electrochemical co-deposition technology and its use as a scaffold for dendrite-free Li metal anode. It is found that the simultaneous formation of this lithiophobic-lithiophilic composite on Cu foam leads to ultrafine lithiophilic phase (20 nm) and reduced Li nucleation overpotential, as well as enhanced homogeneity, which enables a uniform electric field distribution during lithium plating/stripping, thus facilitating even and dendrite-free Li deposition. In the meanwhile, the lithiophobic component in the composite acts as a strong backbone, helping to maintain structural stability during lithium storage. Also, the as-prepared three-dimensional micro/nanoporous scaffold with large surface area can effectively reduce the local current density and suppress Li dendrite growth. The full cells with the composite architecture/Li as anode and LiFePO4 as cathode show promising electrochemical performance with over 80% capacity retention over 1600 cycles at 5 C. This work broadens the horizon of lithiophilic hosts for next-generation high-performance Li metal batteries.