Ultrafine TiO2 confined in porous-nitrogen-doped carbon is synthesized from a single metal–organic framework precursor. As a novel interlayer for lithium–sulfur batteries, the TiO2@NC composite can act as both a high efficiency lithium polysulfide barrier to suppress the side reactions and an additional current collector to enhance the polysulfide redox reactions. The lithium–sulfur battery with a TiO2@NC interlayer delivers a high reversible capacity of 1460 mAh g–1 at 0.2 C and capacity retention of 71% even after 500 cycles with high rate capability.Keywords: interlayer; lithium−sulfur battery; metal−organic framework; nitrogen-doped carbon; TiO2;

Sodium-ion batteries (SIBs), a potential alternative to lithium ion batteries (LIBs), have attracted remarkable attention recently due to the natural abundance and low-cost of sodium. Here, we have presented a comprehensive study on combining electroless deposition with chemical dealloying to control the shell thickness and composition of a red phosphorus (RP)@Ni–P core@shell nanostructure as a high performance anode for SIBs. For the first time depending on regulating the dealloying time (1 h, 4 h, 8 h, 10 h and 20 h) of RP@Ni–P synthesized by electroless deposition of Ni on RP, 1 h RP@Ni–P, 4 h RP@Ni–P, 8 h RP@Ni–P, 10 h RP@Ni–P and 20 h RP@Ni–P with different shell thicknesses and compositions were prepared. The in situ generated Ni2P on RP particle surfaces can facilitate intimate contact between RP and a mechanically strong amorphous Ni–P outer shell with a high electronic conductivity, which ensures strong electrode structural integrity, a stable solid electrolyte interphase and ultra-fast electronic transport. As a result, the 8 h RP@Ni–P composite presents a super high capacity (1256.2 mA h gcomposite−1 after 200 cycles at 260 mA gcomposite−1), superior rate capability (491 mA h gcomposite−1 at 5200 mA gcomposite−1) and unprecedented ultralong cycle-life at 5000 mA gcomposite−1 for an RP-based SIB anode (409.1 mA h gcomposite−1 after 2000 cycles). This simple scalable synthesis approach will provide a new strategy for the optimization of core@shell nanostructures, paving the way for mass production of high performance electrodes for SIBs and other energy storage systems.

•Li-metal coated with Olefin is prepared via a simple in-situ method.•Li-S batteries using protected lithium metal anode are investigated.•The coating can significantly improve the cycling performance of Li-S batteries.Lithium metal is considered to be the optimal choice of next-generation anode materials due to its ultrahigh theoretical capacity and the lowest redox potential. However, the growth of dendritic and mossy lithium for rechargeable Li metal batteries lead to the possible short circuiting and subsequently serious safety issues during charge/discharge cycles. For the further practical applications of Li anode, here we report a facile method for fabricating robust interfacial layer via in-situ olefin polymerization. The resulting polymer layer effectively suppresses the formation of Li dendrites and enables the long-term operation of Li metal batteries. Using Li-S cells as a test system, we also demonstrate an improved capacity retention with the protection of tetramethylethylene-polymer. Our results indicate that this method could be a promising strategy to tackle the intrinsic problems of lithium metal anodes and promote the development of Li metal batteries.Download high-res image (151KB)Download full-size image

We achieved excellent anode performance for PIBs based on a metal–organic framework MIL-125(Ti) for the first time. It can deliver a capacity of 208 mA h g−1 at a rate of 10 mA g−1 and a high capacity retention of 90.2% after 2000 cycles at a high rate of 200 mA g−1 with a high coulombic efficiency. The K+ storage mechanism is investigated by the ex situ XRD and IR techniques and confirms that potassium ions are reversibly inserted into the organic moiety without direct engagement of Ti ions.

We have presented a comprehensive study of using chemical dealloying methods to control the morphology of nanoporous-antimony (NP-Sb) and the size of Sb particles. For the first time, depending on the regulation of the Al–Sb alloy composition, coral-like NP-Sb (NP-Sb70), honeycomb-like NP-Sb (NP-Sb80) and Sb particles (Sb10, Sb30 and Sb45) with different sizes were prepared through chemical dealloying of Al30Sb70, Al20Sb80, Al90Sb10, Al70Sb30 and Al55Sb45 (at%) alloy ribbon precursors respectively, a top-down process. The NP-Sb70 delivered a high capacity of 573.8 mA h g−1 after 200 cycles at a rate of 100 mA g−1 with good rate capability as anode for sodium-ion batteries (SIBs). The excellent electrochemical performance is because of its innovative electrode design, which ensures strong structural integrity, high sodium ion accessibility, and fast electrode transport. This scalable strategy shall pave the way for the mass production of large-capacity electrodes for SIBs and other energy storage systems, providing new guidelines for the optimization of the synthesis of nanostructures.

For the first time, arrayed bismuth (Bi) nanorod bundles were prepared by chemical dealloying of Al30Bi70 (at%) alloy ribbon, using a top-down process. The arrayed Bi nanorod bundles exhibit a high retention capacity of 301.9 mA h g−1 after 150 cycles at a rate of 50 mA g−1, a flat potential profile and good rate capability as an advanced anode for sodium-ion batteries (SIBs). The excellent electrochemical performance is due to high ion accessibility and fast electron transport of arrayed Bi nanorod bundles, which is essential to improve the rate capability of SIBs. This scalable strategy will pave the way for the mass-production of large-capacity electrodes for SIBs and other energy-storage systems, providing new guidelines for the preparation of 1-D nanostructured arrays.

Owing to the natural abundance and low standard potential of sodium, sodium-ion batteries are now considered to be promising power systems for electric vehicles and stationary energy storage. Herein, for the first time, we report the synthesis of VO2 nanowire, nanobelt and nanosheet arrays with preferential (110) orientation on conductive titanium foil by a simple time-dependent hydrothermal method. The morphological and crystallization evolution processes of these products are investigated via XRD, SEM, Raman and TEM in detail. The effect of VO2 morphology on sodium storage performance is also probed by charge–discharge and EIS. Benefiting from the unique morphological features, the VO2 nanowire array shows a superior cycle ability of 160 mA h g−1 after 200 cycles and high rate ability even at 1 A g−1.

A novel additive is investigated as a bifunctional electrolyte additive for 5 V-class lithium ion batteries. It was found that the additive can be electro-polymerized at 5.05 V (vs. Li/Li+), which would protect the batteries from voltage runaway. Moreover, this additive could lower the electrolyte's self-extinguishing time (SET). The influence of this additive on cycling performance and capacity is positive, which makes it promising.

•Carbon coated copper sulfides nanosheets synthesized via directly sulfurizing Metal-Organic Frameworks.•Carbon coated copper sulfides nanosheets are test as cathode for lithium batteries.•The as-prepared C@Cu1.96S nanosheets deliver promising electrochemical performance.Carbon coated copper sulfides nanosheets, denoted as C@Cu1.96S, are successfully prepared via directly annealing Metal-Organic Framework (HKUST-1) and commercial sulfur powder. As cathode materials for lithium batteries, the as-prepared C@Cu1.96S nanosheets deliver high reversible capacity, good capacity retention and superior rate capability.

Sodium batteries are now considered as promising low-cost alternatives for lithium batteries. However, safety problems such as fire and explosion during abuse-testing conditions hinder the development of room temperature sodium batteries. To address these issues, here we propose a nonflammable electrolyte system for sodium batteries. By introducing a high-efficiency flame-retarding additive, the carbonate based electrolyte becomes flame inhibiting. Moreover, the additive can improve the cyclability of both the acetylene black (AB) anode and the Na0.44MnO2 cathode.

•Four nonflammable organic compounds were tested as electrolyte solvents for sodium batteries.•MFE is stable with sodium metal.•Prussian blue and carbon nanotubes were test as cathode and anode materials for sodium batteries in MFE based electrolytes.•Prussian blue and carbon nanotubes are workable in the MFE based electrolyte.Safety problem is one of the key points that hinder the development of room temperature sodium batteries. In this paper, four well-known nonflammable organic compounds, Trimethyl Phosphate (TMP), Tri(2,2,2-trifluoroethyl) phosphite (TFEP), Dimethyl Methylphosphonate (DMMP), Methyl nonafluorobuyl Ether (MFE), are investigated as nonflammable solvents in sodium batteries for the first time. Among them, MFE is stable towards sodium metal at room temperature. The electrochemical properties and electrode compatibility of MFE based electrolyte are investigated. Both Prussian blue cathode and carbon nanotube anode show good electrochemical performance retention in this electrolyte. The results suggest that MFE is a promising option as nonflammable electrolyte additive for sodium batteries.

•V2O5 arrays with different morphologies are constructed on titanium foil for the first time.•The morphologies of V2O5 are time-dependent.•The V2O5 arrays are charactered as binder free cathode materials for sodium battery.•The sodium storage performance of V2O5 array is morphology-dependent.•EIS and Ex-situ SEM were performed to study the mechanism of the performance difference.Herein, we report the synthesis of orthorhombic V2O5 array with hair-like, javelin-like and wall-like structures on conductive titanium foil by a simple time-dependent hydrothermal method. The morphological evolution process of this product has been investigated in detail. The affection of morphology on sodium storage performance is probed. Benefitting from the unique javelin-like structure, the orthorhombic V2O5 array shows a prolonged cycle ability and high rate ability. Ex-Situ scanning electron microscope (SEM) and electrochemical impedance spectroscopy (EIS) are performed to clarify the mechanism.

Sodium batteries are considered as a promising low-cost alternative for currently used lithium batteries. However, safety problems such as overcharge may be a key hindrance for their wide-spread applications. In this study, an aromatic compound (biphenyl) is investigated as an overcharge protection additive for sodium batteries. It is found that BP can be electro-polymerized at 4.3 V (vs. Na/Na+), which protects the Na0.44MnO2/Na batteries from voltage runaway for more than 800% overcharge capacity by consuming the overcharge current. The influence of proper BP addition on the cycling performance and capacity is negligible. Thus, BP can be used as an overcharge additive for sodium batteries. The results may also be helpful for the further research of safer sodium battery systems.

We successfully prepared advanced Ni3P–Ni array electrodes for Li-ion batteries (LIBs) by electroless deposition on 3-D nickel foam. The array structure of Ni3P–Ni can accommodate volume changes during the lithiation/de-lithiation process and promote high-rate capability because the interspaces in such structure can act as ideal volume expansion buffers. It shows excellent electrochemical performance as anode material for LIBs.

•Nanoporous germanium (np-Ge) was firstly prepared by chemical dealloying.•The scalable technique allows for mass production of electrodes for LIBs.•Nanoporous structure can accommodate volume changes and high-rate operation.•Np-Ge exhibits high retention capacity and good rate capability for LIB anode.For the first time nanoporous germanium (np-Ge) was prepared by chemical dealloying allowing for mass production of electrodes for LiBs. Nanoporous structure can accommodate volume changes during the lithiation/de-lithiation progress and promote high-rate capability. The np-Ge shows a promising electrochemical performance as an advanced anode materials for LIBs with a specific capacity of 1191 mA h g−1 after 160 cycles at a rate of 160 mA g−1 and good rate capability.

•The CdCO3/carbon nanotube nanocomposites are synthesized via a facile solution method.•CdCO3 and CdCO3/carbon nanotube nanocomposites could be used as high capacity anode for lithium ion batteries with an alloying/de-alloying mechanism.•Compared to the pure CdCO3, the CNTs/CdCO3 nanocomposites showed a improved cycle stability.Well dispersed CdCO3/carboxylated carbon nanotubes (CNTs) nanocomposites are synthesized via a facile solution method. As a novel anode material for lithium-ion batteries, the CdCO3/CNTs nanocomposites deliver an initial reversible capacity of 876 mAh g−1 and a better cycle ability. The superior electrochemical performance can be attributed to its unique hierarchy architecture, which facilitate the electron transport and accommodate the large volume change during the alloying/de-alloying reactions.

•The porous ZnCO3 is synthesized via a facile solid state method.•ZnCO3 is first characterized as an anode material for lithium ion batteries.•Porous ZnCO3 could be used as a high performance anode for lithium ion batteries with a mixed mechanism.ZnCO3 nanoparticle aggregations with porous morphology are prepared via a facile solid-state metathesis reaction in ambient environments. For the first time, ZnCO3 is characterized as a novel anode material for lithium-ion batteries. The porous ZnCO3 delivers an initial reversible capacity of 735 mAh g−1 and good rate ability. The good electrochemical performance can be attributed to its unique hierarchy architecture, which facilitates the ion transport and buffers the large volume change during the alloying/de-alloying reactions.

•Cd2Ge2O6/reduced graphene oxide nanocomposites were synthesized via a facile one-pot hydrothermal reaction for the first time.•Cd2Ge2O6 and Cd2Ge2O6/reduced graphene oxide nanocomposites were characterized as lithium storage materials for the first time.•Cd2Ge2O6/reduced graphene oxide nanocomposites delivered high capacity and good cycle ability.Well dispersed chestnut-like Cd2Ge2O6 (CGO) and Cd2Ge2O6/reduced graphene oxide (CGO/RGO) nanocomposites are successfully prepared via a facile one-pot hydrothermal method and characterized as novel lithium storage materials for the first time. Electrochemical characterization of lithiation/delithiation of the CGO/RGO nanocomposites reveals a large capacity of 943 mAh g−1 for the first cycle and a capacity retention of 721 mAh g−1 even after 100 cycles. The superior electrochemical performance of the CGO/RGO nanocomposites electrode compared to the pure CGO electrode can be attributed to the well dispersed RGO which enhances the electronic conductivity and accommodate the volume change during the lithium storage process.

Graphene@nitrogen doped carbon@ultrafine TiO2 nanoparticles (G-NC@TiO2) with porous structure are obtained through annealing the precursor of graphene oxide/metal–organic frameworks (MOFs) for the first time. As an anode material for sodium ion batteries (SIB), the G-NC@TiO2 composite can deliver an excellent capacity retention of 93% even after 5000 cycles, and a superior rate capability.

We achieved excellent anode performance for PIBs based on a metal–organic framework MIL-125(Ti) for the first time. It can deliver a capacity of 208 mA h g−1 at a rate of 10 mA g−1 and a high capacity retention of 90.2% after 2000 cycles at a high rate of 200 mA g−1 with a high coulombic efficiency. The K+ storage mechanism is investigated by the ex situ XRD and IR techniques and confirms that potassium ions are reversibly inserted into the organic moiety without direct engagement of Ti ions.

For the first time, arrayed bismuth (Bi) nanorod bundles were prepared by chemical dealloying of Al30Bi70 (at%) alloy ribbon, using a top-down process. The arrayed Bi nanorod bundles exhibit a high retention capacity of 301.9 mA h g−1 after 150 cycles at a rate of 50 mA g−1, a flat potential profile and good rate capability as an advanced anode for sodium-ion batteries (SIBs). The excellent electrochemical performance is due to high ion accessibility and fast electron transport of arrayed Bi nanorod bundles, which is essential to improve the rate capability of SIBs. This scalable strategy will pave the way for the mass-production of large-capacity electrodes for SIBs and other energy-storage systems, providing new guidelines for the preparation of 1-D nanostructured arrays.

Sodium batteries are now considered as promising low-cost alternatives for lithium batteries. However, safety problems such as fire and explosion during abuse-testing conditions hinder the development of room temperature sodium batteries. To address these issues, here we propose a nonflammable electrolyte system for sodium batteries. By introducing a high-efficiency flame-retarding additive, the carbonate based electrolyte becomes flame inhibiting. Moreover, the additive can improve the cyclability of both the acetylene black (AB) anode and the Na0.44MnO2 cathode.