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Two-dimensional (2D) materials combined with carbonaceous materials have shown remarkable properties for boosting the performance of lithium-ion batteries (LIBs). Precise spatial modulation and accurate transmission characteristics of electronic conductivity require good contact between materials. Herein, the preparation of a molybdenum disulfide/polyacrylonitrile-derived carbon (MoS2/PDC) composite by heat treatment in argon atmosphere at 600 °C is presented. The polyacrylonitrile (PAN) and MoS2 are subjected to phase inversion preparation membrane and lignin-assisted exfoliation pretreatment, respectively. The MoS2 nanosheets can enter into the pore of PAN membrane and from C–S bonds during carbonization process, providing effective electron transport paths. Highly conductive carbonized PAN layer can act as an electron collector and provides the volume expansion space for MoS2. Cell tests indicate that the MoS2/PDC electrode exhibits an ultra-high lithium-ion storage capacity of 1354 mAh g−1 at a current density of 0.1 A g−1 and excellent cycling stability. With the advantages of low cost, green process and high electrochemical performance, the MoS2/PDC composite is a promising anode material of LIBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • The change of solvation structure inhibits the decomposition of water. • The hydrogen bonding network constructed limits the activity of water. • Aldehyde groups react with hydrogen to purify electrolyte environment. • The electrostatic shielding layer regulates Zn deposition. Dendrite growth and by-products seriously worsen the operating environment of aqueous zinc ion batteries (AZIBs). In view of these problems, we report a natural multifunctional additive, gum arabic (GA), to optimize ZnSO 4 electrolyte system for achieving longer plating/stripping process of AZIBs. The strong combination between Zn2+ and polar functional groups of GA can weaken the solvation of Zn2+ with water, thus inhibiting the decomposition of water. In addition, hydroxyl groups extend the hydrogen bond network of the electrolyte, further limiting the activity of water molecules. Meanwhile, aldehyde groups can consume the hydrogen generated to purify the electrolyte environment. It is mainly reflected in smaller exchange current density, wider electrochemical window and dendritic-free Zn metal interface. Under the action of GA, the Zn//Zn symmetric battery achieved 3600 h of stable operation (2.5 mA cm−2, 0.5 mAh cm−2) and the Zn//Cu asymmetric battery achieved up to 500 cycles with average 99.1% coulombic efficiency (0.5 mA cm−2, 0.5 mAh cm−2). In addition, Zn//V 2 O 5 full battery also displays a superior capacity retention and rate performance, far surpassing that using pure ZnSO 4 electrolyte. [ABSTRACT FROM AUTHOR]

Tin dioxide (SnO2) is recognized as one of the most promising anode materials for lithium-ion batteries. However, the large volume changes of pure SnO2 anodes during Li+ insertion/extraction inevitably result in rapid capacity decay. Herein, the fabrication of microsized, porous SnO2/Sn/carbon (p-SnO2/Sn/C) composites by a straightforward one-step hydrothermal process with triblock copolymer Pluronic F-127 as templating agent and subsequent carbonization is reported. In this composite structure, SnO2/Sn nanoparticles (≈5 nm) are uniformly embedded in an ordered porous carbon matrix to form an interpenetrating framework structure. The ordered porous carbon matrix not only offers three-dimensional channels for extraction/insertion of Li+ during cycling, but also buffers severe volume changes of the SnO2/Sn nanoparticles. Furthermore, the composite structure also ensures formation of stable solid electrolyte interface films as compared with isolated SnO2/Sn nanoparticles, which efficiently improves the electrochemical stability of the active materials. Thus, the p-SnO2/Sn/C anode delivers a high reversible capacity of 1016.2 mAh g−1 at 100 mA g−1 after 100 cycles and has remarkable long-term cycle stability (a charge capacity of 710 mAh g−1 even after 600 cycles at 1000 mA g−1). [ABSTRACT FROM AUTHOR]

Carbon coated K0.8Ti1.73Li0.27O4 (KTLO) has been synthesized by a facile flux method followed by ball-milling and gaseous carbon coating. The carbon coated KTLO delivers a reversible specific capacity of 119.6 mA h g−1 at 20 mA g−1 with no capacity loss after 250 cycles as an anode material in sodium ion batteries, exhibiting an improved rate capability of 66 mA h g−1 at 200 mA g−1. It was found that carbon coating of KTLO not only enhances its electronic conductivity, but also improves the structure stability, proving that the carbon coated KTLO is a promising anode material for sodium ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: The double perovskite Sr2CoMoO6−δ was investigated as a candidate anode for a solid oxide fuel cell (SOFC). Thermogravimetric analysis (TGA) and powder X-ray diffraction (XRD) showed that the cation array is retained to 800°C in H2 atmosphere with the introduction of a limited concentration of oxide–ion vacancies. Stoichiometric Sr2CoMoO6 has an antiferromagnetic Néel temperature T N ≈37K, but after reduction in H2 at 800°C for 10h, long-range magnetic order appears to set in above 300K. In H2, the electronic conductivity increases sharply with temperature in the interval 400°C< T <500°C due to the onset of a loss of oxygen to make Sr2CoMoO6−δ a good mixed oxide–ion/electronic conductor (MIEC). With a 300-μm-thick La0.8Sr0.12Ga0.83Mg0.17O2.815 (LSGM) as oxide–ion electrolyte and SrCo0.8Fe0.2O3−δ as the cathode, the Sr2CoMoO6−δ anode gave a maximum power density of 1017mWcm−2 in H2 and 634mWcm−2 in wet CH4. A degradation of power in CH4 was observed, which could be attributed to coke build up observed by energy dispersive spectroscopy (EDS). [ABSTRACT FROM AUTHOR]

Abstract: The electrolyte of a solid oxide fuel cell (SOFC) is an O2−-ion conductor. The anode must oxidize the fuel with O2− ions received from the electrolyte and it must deliver electrons of the fuel chemisorption reaction to a current collector. Cells operating on H2 and CO generally use a porous Ni/electrolyte cermet that supports a thin, dense electrolyte. Ni acts as both the electronic conductor and the catalyst for splitting the H2 bond; the oxidation of H2 to H2O occurs at the Ni/electrolyte/H2 triple-phase boundary (TPB). The CO is oxidized at the oxide component of the cermet, which may be the electrolyte, yttria-stabilized zirconia, or a mixed oxide-ion/electron conductor (MIEC). The MIEC is commonly a Gd-doped ceria. The design and fabrication of these anodes are evaluated. Use of natural gas as the fuel requires another strategy, and MIECs are being explored for this application. The several constraints on these MIECs are outlined, and preliminary results of this on-going investigation are reviewed. [Copyright &y& Elsevier]

• A multi-component composite protective layer is designed to stabilize Li metal anode by a simple drop casting reaction. • This multi-component composite protective layer can effectively reduce the occurrence of side reactions. • This multi-component composite protective layer keeps the Li plating/striping cycle under a stable interface. • This multi-component composite protective layer plays a role in alleviate the corrosion of Li metals by air. • The ultra-long cycle life of symmetric batteries as well as Li/LTO full battery is achieved. Lithium (Li) metal anode is regarded as the "Holy Grail" due to its high theoretical specific capacity and low electrochemical redox potential. However, the poor battery life and serious safety concerns caused by uncontrolled growth of Li dendrites and the extreme instability of the interface during long-term Li plating/striping process have always been obstacles to the commercialization of Li metal batteries (LMBs). Herein, a multi-component composite protective layer (MCPL) consisted of Li-Zn alloy, LiBr and organic products for stabilizing Li metal anode is prepared by multiple chemical reactions on Li metal anode. Under the protection of this artificial protective layer, the modified Li metal anode reduces the risk of excessive corrosion by electrolyte, and keeps the Li plating/striping cycle under a stable interface, which greatly reduces the formation of Li dendrites and the volume expansion effect. As a result, the symmetric Li/Li battery with multi-component composite protective layer shows better cycling stability at the current density of 0.5 mA cm−2 with a super-flat voltage plateau for about 4000 h. More importantly, the Li/Li 4 Ti 5 O 12 full batteries show superior C-rate performance and higher capacity retention rate of 85.2% after 1000cycles at 1.0C. Furthermore, MCPL can effectively alleviate air corrosion, greatly reducing assembly and storage risks. This work provides a simple and effective method for achieving safe LMBs by designing a reasonable multi-component composite artificial protective layer. [ABSTRACT FROM AUTHOR]

Lithiophilic viscoelastic interface achieves good cycling performance by regulating the uniform deposition of Li+ and adapting to the volume expansion of lithium. • A viscoelastic polymer is used to stabilize lithium metal anode. • The abundant polar functional groups in HPMC molecules can better regulate the uniform deposition of lithium. • The viscoelastic interface shows better mechanical strength and elasticity. • The viscoelastic interface can adhere to the lithium metal anode surface well during cycling process. • A smoother lithium surface after long-term cycle is achieved. Due to higher theoretical specific capacity and lower electrochemical redox potential, lithium metal is considered an ideal anode material for high specific energy batteries. However, safety problems related to the uncontrolled growth of lithium dendrites and the volume expansion of lithium have hindered its commercialization. This paper reports a viscoelastic interface based on viscoelastic polymer (hydroxypropyl methyl cellulose) to protect lithium metal anode. The lithiophilic interface has good chemical, electrochemical and mechanical stability, which makes the dendrite-free and low volume expansion lithium possible. The Li/Li symmetrical battery based on anode protected by viscoelastic interface show better cycle stability and longer cycle life. The morphologies after cycles show a relatively smooth and dense lithium deposition. Li/LFP full battery test results show higher reversible capacity at higher C-rate, high capacity retention (85.2%) and stable coulomb efficiency (99.5%) at 0.2C after 200 cycles. This work provides insight into the strategy of interfacial engineering to protect lithium metal anode. [ABSTRACT FROM AUTHOR]

[Display omitted] Lithium ion capacitors (LICs) are a new generation of energy storage devices that combine the super energy storage capability of lithium ion batteries with the satisfactory power density of supercapacitors. The development of high-performance LICs still faces great challenges due to the unbalanced reaction kinetics at the anode and cathode. Therefore, it is an inevitable need to enhance the electron/ion transfer capability of the anode materials. In this paper, to obtain a superior-rate and high-capacity Ni 3 S 2 -based anode, highly conductive Ti 3 C 2 T x MXene sheets were introduced to sever as the carrier of Ni 3 S 2 nanoparticles and simultaneously an amorphous carbon layer which coats onto the surface of Ni 3 S 2 nanoparticles was in-situ generated by the carbonization of dopamine reactant. The as-synthesized Ni 3 S 2 /Ti 3 C 2 T x /C composite exhibits a high specific surface area (112.6 m2/g) because of the addition of Ti 3 C 2 T x that can reduce the aggregation of Ni 3 S 2 nanoparticles and the in-situ generated amorphous carbon layer that can suppress the growth of Ni 3 S 2 nanoparticles. The Ni 3 S 2 /Ti 3 C 2 T x /C anode possesses a remarkable reversible discharge specific capacity (626.0 mAh/g under 0.2 A/g current density), which increases to 1150.8 mAh/g after 400-cycle charge/discharge measurement at the same measurement condition indicating eminent cyclability, along with superior rate capability. To construct a superior-performance LIC device, a sterculiae lychnophorae derived porous carbon (SLPC) cathode with an average discharge specific capacity of 73.4 mAh/g@0.1A/g was prepared. The Ni 3 S 2 /Ti 3 C 2 T x /C//SLPC LIC device with optimal cathode/anode mass ratio has a satisfactory energy density ranging from 32.8 to 119.1 Wh kg−1 at the corresponding power density of 8799.4 to 157.5 W kg−1, together with a prominent capacity retention (95.5 %@1 A/g after 10,000 cycles). [ABSTRACT FROM AUTHOR]

Silicon is the one of the most promising anode material alternatives for next-generation lithium-ion batteries. However, the low electronic conductivity, unstable formation of solid electrolyte interphase, and the extremely high volume expansion (up to 300%) which results in pulverization of Si and rapid fading of its capacity have been identified as primary reasons for hindering its application. In this work, we put forward to introduce dual carbonaceous materials synergetic protection to overcome the drawbacks of the silicon anode. The silicon nanoparticle was coated by pyrolysed carbon, and meanwhile anchored on the surface of reduced graphene oxide, to form a self-standing film composite (C@Si/rGO). The C@Si/rGO film electrode displays high flexibility and an ordered porous structure, which could not only buffer the Si nanoparticle expansion during lithiation/delithiation processes, but also provides the channels for fast electron transfer and lithium ion transport. Therefore, the self-standing C@Si/rGO film electrode shows a high reversible capacity of 1002 mAh g−1 over 100 cycles and exhibits much better rate capability, validating it as a promising anode for constructing high performance lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The growth of dendritic dendrites and side reactions at the zinc anode result in poor cycling stability of the aqueous zinc-ion battery (AZIBs). Here, we report on a multifunctional additive, Sodium lactobionate (SL), that achieves more stable cycling performance. SL molecule can loosen the solvation structure of water and Zn2+, inhibit corrosion and hydrogen evolution reactions, and regulate ion deposition in AZIBs. Under the action of SL, the Zn//Zn symmetric battery achieves an ultra-long stable cycle of up to 2150 h at a current density of 2 mA·cm−2 and an area capacity of 1 mAh cm−2 and Zn//NVO can still perform 1110 cycles at the current density of 2 A g−1 and maintain the reversible specific discharge capacity of 179 mAh g−1. In addition, at 2 mA cm−2 and 0.5 mAh cm−2, the Zn//Cu asymmetric battery achieved up to 350 cycles with a coulomb efficiency of 99.5 %. • Sodium lactobionate can change the solvation structure of water and Zn2+. • Inhibit corrosion and regulate ion deposition. • Zn.||Zn symmetric cell exhibits a cycling of 2150 h at 2 mA cm−2, 1 mAh cm−2. • 4.Zn.||NVO full cell shows 76.4 % retention after 1100 cycles at 2 A g−1. [ABSTRACT FROM AUTHOR]

• The construction of the artificial SEI layer is realized by a common solvent DMSO. • The components of Li 2 SO 4 and sulfur-containing organic compounds in SEI are helpful to stabilize the lithium anode. • A facile strategy to construct artificial SEI through chemical reaction for lithium metal batteries is proposed. Lithium metal is considered one of the most promising anode materials because of its high theoretical capacity and the lowest electrode potential, but practical application is hampered by high reactivity and volume variation in circulation. As a key component, the artificial solid electrolyte interphase (SEI) is designed to effectively stabilize the lithium anode. Here, the chemical reaction between dimethyl sulfoxide (DMSO) and lithium is accelerated in the presence of potassium hydroxide (KOH). The sulfur-containing organic compounds, lithium sulfate (Li 2 SO 4), lithium hydroxide (LiOH) and other favorable components are introduced into SEI, which enable the modified lithium metal anode to have lower interfacial impedance, higher lithium ion transference number, and more uniform Li-ion deposition. The assembled Li-Li symmetric battery realizes a stable cycle of more than 800 h at a current density of 0.5 mA cm−1 and an areal capacity density of 1 mAh cm−1. The full cell coupled with LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) still maintains 113 mAh g−1 discharge capacity with 63% capacity retention rate after 400 cycles at a current density of 0.5 C. The simple construction of artificial SEI strategy of this study provides an effective strategy for LMBs with superior electrochemical performance. [Display omitted] [ABSTRACT FROM AUTHOR]

Transition metal sulfides as a high specific capacity sodium-ion batteries (SIBs) anode which have been suffering from successive phase transitions bringing about stress changes, poor electronic conductivity and ineffective ion transport kinetics. Combining self-sacrificial templates and ion-exchange transition reaction mechanisms, herein, cobalt, vanadium bimetallic sulfides hollow nano-cubic boxes with nitrogen-doped nanocarbon coating layer (CoV 2 S 4 @NC) are designed to solve these symbiosis problems. With a combination of in-situ Raman, ex-situ XPS/TEM, and density-functional theory calculations, the synergistically coordination mechanism between cobalt and vanadium binary metal during multi-step conversion processes is responsible for the faster charge transfer kinetics and boosted Na+ pseudocapacitance storage capability. Furthermore, the hollow cubic structure combined with the carbon shell layer can release the internal stress during phase transitions and avoid the recurrent growth of SEI film by volume change during the electrochemical process, thus realizing a superior electrode/electrolyte interface. Thus, when used as anode materials for SIBs, the prepared anode materials display excellent electrochemical performance, delivering capacity of 492 mA h g−1 at a current density of 10 A g−1 and high capacity stability with 484 mAh g−1 after 1000 cycles at 5 A g−1. More importantly, the assembled full cell (Na 3 V 2 (PO 4) 3 //CoV 2 S 4 @NC) also shows high capacity of 574 mAh g−1 with 94.7% capacity retention after 85 cycles, suggesting the potential application of bimetallic sulfides in SIBs. [Display omitted] • CoV 2 S 4 @NC bimetallic sulfides hollow nano-cubic boxes is designed. • Coordination mechanism between binary metals during multistep reaction in CoV 2 S 4. • It realizes fast charge transfer kinetics and boosted Na + pseudocapacitance storage. [ABSTRACT FROM AUTHOR]

Abstract: Double-perovskite Ba2MMoO6 (M=Fe, Co, Mn, Ni) has been systematically investigated as anode materials for solid oxide fuel cells (SOFCs). Among these materials, Ba2FeMoO6 shows the best electrochemical performance with maximum power density of 605mWcm−2 and electronic conductivity of 196Scm−1 at 850°C in H2. Thermal expansion coefficients of Ba2MMoO6 are distributed within the range of (10−18)×10−6 K−1, matching well with that of La0.8Sr0.2Ga0.83Mg0.17O3−δ electrolyte. Thermogravimetric analysis (TGA) clearly indicates that oxygen vacancies are formed in all the Ba2MMoO6 materials. For the Ba2MMoO6 anodes, the power output decreases in the order of M=Fe>M=Co>M=Mn>M=Ni; the overpotential increases in the order of M=Fe

Li metal is considered as a "Holy Grail" anode material for Li metal batteries (LMBs). Unfortunately, the interface problems including the interface reaction of lithium metal anode and the generation of lithium dendrite between lithium metal anode and electrolyte are still the major obstacles in the practical application of LMBs. Here, a novel gel polymer electrolyte (GPE) is attempted to solve these issues. The membrane of polymer composite matrix is successfully prepared by blending hydroxypropyl methyl cellulose (HPMC) with polyacrylonitrile (PAN) through a simple phase inversion method, and finally the corresponding GPE is obtained by an activation process in electrolyte. The polymer composite membrane overcomes some shortcomings of traditional PAN matrix, and meanwhile the corresponding GPE exhibits superior electrochemical performances. As a result, an ultralong-term reversible lithium plating/stripping cycle at a moderate current density (1 mA cm−2) with dendrite-free is achieved for lithium metal anodes. The full cell test results show a higher reversible capacity (106 mAh g−1) at 2C, capacity retention (94.2%) after 100 cycles and a stable coulomb efficiency (98.9%). This study emphasizes the capacity of the designed GPE in stabilizing lithium metal anode and opens a new perspective on the synergy of between different materials. [ABSTRACT FROM AUTHOR]

Lithium-ion capacitors (LICs) are considered as a promising energy storage device possessing large specific energy along with high specific power due to the integration of the merits of electric double-layer capacitors (ELDCs) and lithium-ion batteries (LIBs). In the present work, TiO 2 nanotubes supported ultrafine MnCo 2 O 4 nanoparticles with the size of 5–10 nm is solvothermally synthesized. It is found that the introduction of TiO 2 nanotubes can weaken the aggregation of MnCo 2 O 4 nanoparticles, therefore causing the enhancement in the electrode/electrolyte interfacial contact and the reduction in Li + diffusion path. Benefiting from the synergy effect of MnCo 2 O 4 and TiO 2 which can alleviate the volume change of MnCo 2 O 4 , the MnCo 2 O 4 /TiO 2 composite used in LIBs displays a large reversible capacity of 743 mAh g−1 at 0.2 A g−1 after 100 cycles and impressive rate performance. This composite as anode is assembled with an activated carbon (AC) electrode as cathode into MnCo 2 O 4 /TiO 2 //AC LIC working in a wide voltage range of 0.5–4 V. This LIC can deliver high specific energies of 89.8 and 44.1 Wh kg−1 at specific power of 0.25 and 3.41 kW kg−1, respectively, and presents outstanding cyclic stability (76.4% of initial capacity at the end of 5000 cycles). A high-performance MnCo 2 O 4 /TiO 2 composite was synthesized and used as an anode of Li-ion capacitors. [Display omitted] • TiO 2 nanotubes are employed to support ultrafine MnCo 2 O 4 nanoparticles. • MnCo 2 O 4 /TiO 2 composite can deliver high reversible capacity. • A Li-ion capacitor is assembled by using MnCo 2 O 4 /TiO 2 composite as anode. • The Li-ion capacitor shows high specific energy and specific power. [ABSTRACT FROM AUTHOR]

MnO is a promising anode material for LIBs due to its low cost and high theoretical capacity, but large volume changes and low conductivity limit its application. To improve its conductivity and electron transport rate, we fabricated mesoporous MnO/C hollow microtube through a hydrodynamic force-induced rapid assembly in T-type microchannel reactor followed with a sintering process. The as-synthesized mesoporous MnO/C hollow microtube is consist of MnO nanograins with abundant porous reaction sites embedding uniformly on carbon layers to form a hollow tubular-like structure. When used this mesoporous MnO/C hollow microtube as an anode material of LIBs, it can deliver a high reversible capacity of 845 mAh·g−1 after 100 cycles at 1.5 A g−1 and a capacity of 699 mAh·g−1 at 3.75 A g−1, exhibiting good rate capability and cycle stability. The temperature-dependence electrochemical impedance spectra showed that the mesoporous hollow microtube structure can decrease the barrier energy for jumping through the SEI film, the intercalation reaction and the diffusion of Li+ in the bulk of the solid. The improved performances can be attributed to the unique mesoporous hollow-tubular structure, which enhances the structural stability, improves the electrical conductivity and fasten electrode reaction kinetics. [ABSTRACT FROM AUTHOR]

Silicon(Si)/graphene composite has been regarded as one of the most promising candidates for next generation anode materials with high power and energy density in lithium ion batteries. Introduction of graphene in Si anodes could improve the electronic conductivity, suppress the severe volume expansion of Si, and facilitate the formation of stable solid electrolyte interphase, etc. However, traditionally mechanical mixing of Si and graphene cannot realize uniform distribution of Si particles on the graphene sheets, which would largely weaken the effectiveness of the graphene in the composite. In this work, nano-Si/reduced graphene oxide porous composite (p Si/rGO) has been fabricated by a facile electrostatic self-assembly approach via using SiO 2 as the sacrificial template. Compared with the simply mechanically mixed nano-Si and rGO (Si/rGO), the nano-Si particles could be more uniformly dispersed among the rGO sheets in the p Si/rGO, which significantly increases its electronic conductivity. Moreover, the drastic volume expansion of nano-Si during repeated lithiation/delithiation cycles also has been effectively accommodated by the large number of pores left after removing the SiO 2 template in the composite. Thus, the p Si/rGO presented largely enhanced electrochemical performances, showing a high reversible capacity up to 1849 mA h g −1 at 0.2 A g −1 with good capacity retention, and high rate capability (535 mA h g −1 at 2 A g −1 ). [ABSTRACT FROM AUTHOR]

The commercial Li 4 Ti 5 O 12 (LTO) is successfully modified by SrF 2 via a low temperature coprecipitation process. The results indicate that Sr 2+ and F − do not co-dope into the bulk phase of the LTO, but instead form a SrF 2 coating layer on the surface of the LTO. The suitable SrF 2 buffer layer could cover the catalytic active sites of the LTO and suppress the electrolyte reduction decomposition on the surface of the LTO, which means that the SrF 2 modification is favorable to suppress gas generation of the LIBs using LTO as anode material during charge/discharge cycles and storage. Moreover, according to optimized the amount of SrF 2 , the 2 wt% of SrF 2 in the SrF 2 modified LTO composites exhibits the best rate capability and an excellent cyclic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • DES was firstly employed to recycle and regenerate waste graphite from spent LIBs. • The impurities in spent graphite were removed efficiently by DES leaching. • DRG exhibited a rather high specific capacity of 449.4 mAh/g for 1st cycle at 0.1C. • The regeneration mechanism of graphite during the DES leaching process was revealed. • The proposed DES treatment had significant economic and environmental benefits. Recovery of graphite from spent lithium-ion batteries (LIBs) as new anode materials in the LIBs after regeneration can not only promote the recycling of spent LIBs, but also help to alleviate its environmental risks. However, the removal of the impurities in spent graphite is unsatisfying and its electrochemical performance need to be further improved when using conventional regeneration methods (such as acid treatment). Herein, we proposed a novel deep eutectic solvent (DES) leaching method to recover and regenerate waste graphite from spent LIBs under mild condition. The result showed that DES leaching could not only effectively remove the impurities in spent graphite, but also restore its crystal structure and morphology. The regenerated graphite obtained by DES treatment (DRG) exhibited a high specific capacity of 449.4 mAh/g for the first cycle at 0.1C and 285.4 mA h/g even after 500 cycles at 1C. In addition, the retention rate and coulombic efficiency of DRG were as high as 96.0 % and 100 %, respectively. These results demonstrated the excellent electrochemical performance of DRG, which was even comparable to that of commercial graphite. The regeneration mechanism of the proposed method was also elucidated. The organic binder was dissolved in DES by forming hydrogen bonds (O H...F and C H...Cl−). The Li coordination complex formed between SEI film and DES contributed to the dissolution of SEI film, and the residual electrolytes were removed based on the similarity-intermiscibility theory. This study provides a facile and green method to accomplish the closed-loop utilization of spent graphite in spent LIBs. [ABSTRACT FROM AUTHOR]

Nano tin dioxide-carbon (SnO 2 /C) composites prepared by various carbon materials, such as carbon nanotubes, porous carbon, and graphene, have attracted extensive attention in wide fields. However, undesirable concerns of nanoparticles, including in higher surface area, low tap density, and self-agglomeration, greatly restricted their large-scale practical applications. In this study, novel porous micron-SnO 2 /C (p-SnO 2 /C) composites are scalable prepared by a simple hydrothermal approach using glucose as a carbon source and Pluronic F127 as a pore forming agent/soft template. The SnO 2 nanoparticles were homogeneously dispersed in micron carbon spheres by assembly with F127/glucose. The continuous three-dimensional porous carbon networks have effectively provided strain relaxation for SnO 2 volume expansion/shrinkage during lithium insertion/extraction. In addition, the carbon matrix could largely minimize the direct exposure of SnO 2 to the electrolyte, thus ensure formation of stable solid electrolyte interface films. Moreover, the porous structure could also create efficient channels for the fast transport of lithium ions. As a consequence, the p-SnO 2 /C composites exhibit stable cycle performance, such as a high capacity retention of over 96% for 100 cycles at a current density of 200 mA g −1 and a long cycle life up to 800 times at a higher current density of 1000 mA g −1 . [ABSTRACT FROM AUTHOR]

Abstract: Hollow porous submicron-sized ZnMn2O4 spheres have been successfully prepared using self-made MnCO3 spheres as template. The morphology and structure evolution of the hollow porous ZnMn2O4 spheres are well examined to achieve optimal electrochemical performance. The SEM image shows that the ZnMn2O4 sample is composed of hollow porous submicron spheres (0.5–1.0μm) formed by nanosized particles with diameters of 25–50nm. The 600°C-sintered sample exhibits the best electrochemical performance. At a current density of 100mAg−1, the discharge capacity is as high as 1260mAhg−1 for the first cycle and retains stably at 599mAhg−1 after 40 cycles. Even at 1000mAg−1, the average specific capacity is still 450mAhg−1. The excellent electrochemical performance can be attributed to its unique feature of hollow porous structure, which may not only buffer the volume variation during discharge/charge process with hollow interior, but also facilitate the electrolyte penetration and thus shorten the transport length of Li+ ions. [Copyright &y& Elsevier]

Abstract: Mn3O4 nanocomposite with multi-walled carbon nanotubes (MWCNTs) has been successfully fabricated via a simple solvothermal route assisted by sodium acetate. Mn3O4 nanocrystals are uniformly anchored on MWCNTs. As anode material for lithium-ion batteries, the nanocomposite exhibits excellent cycling stability and rate capability. It delivers an initial reversible capacity of 1380mAhg−1 at a current density of 100mAg−1, and retains the capacity to 592mAhg−1 after 50 cycles. Even at 1000mAg−1, the capacity is still 387mAhg−1 after 35 cycles. The superior performance is ascribed to the unique architecture with short diffusion length for lithium ions and effective conductive network for electron transport. [Copyright &y& Elsevier]

Abstract: SnO2-based composite coaxial nanocables with multi-walled carbon nanotube (MWCNT) and polypyrrole (PPy), SnO2@MWCNT@SnO2@PPy have been successfully synthesized via a simple one-pot chemical route. Such a novel nanostructure can not only provide a high conductivity, but also effectively suppress mechanical stress and prevent aggregation of SnO2 nanoparticles, leading to the improvement in the electrochemical utilization and cycling stability of SnO2 during Li-storage reaction. As anode materials, the as-obtained coaxial nanocables show a reversible capacity as high as 600mAh g−1 and a coulombic efficiency close to 100%, which is potential for practical application in lithium-ion batteries. [Copyright &y& Elsevier]

[Display omitted] • An oxygen vacancy contained SnO 2 QDs/Ti 3 C 2 T x MXene composite is prepared. • This composite shows high reversible discharge capacity and good rate performance. • A high-capacity N, S co-doped biomass derived porous carbon is prepared. • The LIC presents high energy and power densities, and excellent cyclic stability. Li-ion capacitors (LICs) based on battery-type anodes and capacitive cathodes have the potential to become the candidate of the next generation of electrochemical energy storage (EES) devices because of their high energy density (ED) along with large power density (PD) which are basically determined by the physical and chemical properties of their anodes and cathodes. In this work, the coating of SnO 2 quantum dots (QDs, ca. 4–5 nm) with oxygen vacancies on the surface of Ti 3 C 2 T x MXene sheets with different contents has been achieved through one-step solvothermal method. The optimized SnO 2 QDs/Ti 3 C 2 T x -50 composite anode displays a large reversible discharge capacity (1000.4 mAh g−1@0.2 A g−1), distinguished cycling stability (the discharge capacity of 1004.0 mAh g−1 at the end of 300 cycles under the same current density), and good rate performance, and in which the reaction kinetics is dominated by the fast capacitive process to a large extent, due to the reduced Li+ ion diffusion path and oxygen vacancies in SnO 2 QDs, the prominent electrical conductivity along with outstanding mechanical property for Ti 3 C 2 T x MXene, and the large specific surface area of this composite. And a high-capacity N, S co-doped biomass derived porous carbon (NS-BPC) cathode (95.8 mAh g−1@0.2 A g−1) is synthesized, and constructed with the SnO 2 QDs/Ti 3 C 2 T x -50 anode to give rise to a superior-performance Li-ion capacitor possessing ED being 148.5 to 17.5 Wh kg−1 with the corresponding PD of 200.4 W kg−1 to 10.0 kW kg−1, additionally exceedingly good cycling stability (96.5% capacity retention ratio after 5000 cycles). [ABSTRACT FROM AUTHOR]