Binder-free Ge nanoparticles-carbon hybrids for anode materials of advanced lithium batteries with high capacity and rate capability

We present a facile synthetic route toward binder-free, highly-dispersed Ge nanoparticles in carbon matrices using one-step pyrolysis of self-assembled Ge-polymer hybrids. 3-Dimensionally arranged Ge-carbon exhibits remarkably enhanced cycling properties and rate capability compared with carbon sheathed Ge lacking organization.     

Nano-LiCoO2 as cathode material of large capacity and high rate capability for aqueous rechargeable lithium batteries

Crystalline nanoparticles of LiCoO₂ are prepared by a sol–gel method at 550 °C and characterized by X-ray diffraction. Their electrochemical behaviors were characterized by cyclic voltammograms, capacity measurement and cycling performance. Results show that the reversible capacity of the nano-LiCoO₂ can be up to 143 mAh/g at 1000 mA/g and still be 133 mAh/g at 10,000 mA/g (about 70C) in 0.5 mol/l Li₂SO₄ aqueous electrolyte. In addition, their cycling behavior is also very satisfactory, no evident capacity fading during the initial 40 cycles. These data present great promise for the application of aqueous rechargeable lithium batteries.     

Nb2O5 nanobelts: A lithium intercalation host with large capacity and high rate capability

In this study, Nb₂O₅ nanobelts, with a ca. ∼15 nm in thickness, ca. ∼60 nm in width and several tens of mircrometers in length, have first been used as the electrode material for lithium intercalation over the potential window of 3.0–1.2 V (vs. Li⁺/Li). It delivers an initial intercalation capacity of 250 mA hg⁻¹ at 0.1 Ag⁻¹ current density, corresponding to x = 2.5 for L_xNb₂O₅, and can still keep relative stable and reaches as large as 180 mA hg⁻¹ after 50 cycles. Surprisingly, the electrodes composed of Nb₂O₅ nanobelts can work smoothly even at high current density of 10 Ag⁻¹, and shows higher specific capacity and excellent cycling stable, as well as sloped feature in voltage profile. Cycling test indicates Nb₂O₅ nanobelts electrode shows a high reversible charge/discharge capacity, high rate capability with excellent cycling stability.     

LiMn2O4 hollow nanosphere electrode material with excellent cycling reversibility and rate capability

Lithium-rich Li_1.05Mn₂O₄ hollow nanospheres have been successfully prepared by air-calcining lithiated MnO₂ precursor at a low temperature of 550 °C, which was synthesized by chemical lithiation of hollow MnO₂ nanospheres with LiI at 70 °C for 12 h. The lithium-rich Li_1.05Mn₂O₄ hollow nanospheres exhibit an excellent cycling stability and rate capability as a cathode material for rechargeable lithium batteries: it maintains 90% of its initial capacity after 500 cycles, and keeps 70% of the reversible capacity at 0.1 C rat, even at 15 C rate.     

The role of functional materials to produce high areal capacity lithium sulfur battery

The lithium sulfur batteries(LSBs) are considered as one of the promising next generation energy storage devices due to the high theoretical specific capacity of sulfur(1675 m Ah g-1), naturally available, low cost.However, the practical LSBs are impeded by the well-known "shuttle effect" combined with other technical drawbacks. The "shuttle effect" causes rapid capacity decay, severe self-discharging and low active material utilization. The polysulfide(PS) which has lone pair electrons in each sulfur atom is considered as Lewis base and shows strong affinity to various polar, Lewis acid and catenation interactive materials but very weakly interacts with the non-polar conductive carbons. The "shuttle effect" occurs due to the diffusion of high order PS from the cathode to the anode and then low-order PS back to the cathode. The PS is polar and, due to a lone pair of electrons associated with the sulfur atom, is considered a Lewis base. As such, the PS shows a strong affinity with various polar and Lewis acid materials. In addition, a more novel trapping can be performance through a catenation reaction. For LSBs to compete with the state-of-the-art lithium ion batteries(LIBs), the LSB areal capacity need to be ～6 m Ah cm-2(which is proportional to sulfur loading). To achieve this target the PS shuttling needs to mitigate, which can be achieved through using functional materials. This review addresses the aforementioned phenomena by considering the PS phase interacts with the various functional materials and how this impacts areal capacity and cycling stability of LSBs.     

High reversible capacity and rate capability of ZnCo2O4/graphene nanocomposite anode for high performance lithium ion batteries

A facile and straightforward method was adopted to synthesize ZnCo₂O₄/graphene nanocomposite anode. In the first step, pure ZnCo₂O₄ nanoparticles were synthesized using urea-assisted auto-combustion synthesis followed by annealing at a low temperature of 400 °C. In the second step, in order to synthesize ZnCo₂O₄/graphene nanocomposite, the obtained pure ZnCo₂O₄ nanoparticles were milled with 10 wt% reduced graphene nanosheets using high energy spex mill for 30 s. The ZnCo₂O₄ nanoparticles, with particle sizes of 25–50 nm, were uniformly dispersed and anchored on the reduced graphene nanosheets. Compared with pure ZnCo₂O₄ nanoparticles anode, significant improvements in the electrochemical performance of the nanocomposite anode were obtained. The resulting nanocomposite delivered a reversible capacity of 1124.8 mAh g⁻¹ at 0.1 C after 90 cycles with 98% Coulombic efficiency and high rate capability of 515.9 mAh g⁻¹ at 4.5 C, thus exhibiting one of the best lithium storage properties among the reported ZnCo₂O₄ anodes. The significant enhancement of the electrochemical performance of the nanocomposite anode could be credited to the strong synergy between ZnCo₂O₄ and graphene nanosheets, which maintain excellent electronic contact and accommodate the large volume changes during the lithiation/delithiation process.     

Macroporous Co3O4 platelets with excellent rate capability as anodes for lithium ion batteries

This paper reports the microwave-assisted synthesis of Co₃O₄ nanomaterials with different morphologies including nanoparticles, rod-like nanoclusters and macroporous platelets. The new macroporous platelet-like Co₃O₄ morphology was found to be the best suitable for reversible lithium storage properties. It displayed superior cycling performances than nanoparticles and rod-like nanoclusters. More interestingly, excellent high rate capabilities (811 mAh g^?1 at 1780 mA g^?1 and 746 mAh g^?1 at 4450 mA g^?1) were observed for macroporous Co₃O₄ platelet. The good electrochemical performance could be attributed to the unique macroporous platelet structure of Co₃O₄ materials.     

Enlarging Zn deposition space via regulating Sn-induced effective interface for high areal capacity zinc-based flow battery

Zinc-based flow batteries(ZFBs) have aroused great favor in large-scale energy storage due to the high security and low cost.However,the low areal capacity arising from the limited space for Zn plating hinders the further development.Herein,a novel carbon felt-Sn-carbon felt sandwich host(CSCH) is designed and constructed.Benefiting from the strong chemical absorption and the dehydration effect on Zn(H₂O)₆²⁺,the Sn activation layer in the CSCH demonstrates the lo...     

Pyridinic nitrogen enriched porous carbon derived from bimetal organic frameworks for high capacity zinc ion hybrid capacitors with remarkable rate capability

Aqueous zinc ion hybrid capacitors(ZIHCs)hold great potential for large-scale energy storage applications owing to their high safety and low cost,but suffer from low capacity and energy density.Herein,pyridinic nitrogen enriched porous carbon(nPC)was successfully synthesized via the growth,subsequent annealing and acid etching of bimetal organic frameworks for high capacity and safe ZIHCs with exceptional rate capability.Benefiting from the mesopores for easy ion diffusion,high electrical conductivity enabled by in-situ grown carbon nanotubes matrix and residual metal Co nanoparticles for fast electron transfer,sufficient micropores and high N content(8.9 at%)with dominated pyridinic N(54%)for enhanced zinc ion storage,the resulting nPC cathodes for ZIHCs achieved high capacities of 302 and137 m Ah g^-1 at 1 and 18 A g^-1,outperforming most reported carbon based cathodes.Theoretical results further disclosed that pyridinic N possessed larger binding energy of-4.99 eV to chemically coordinate with Zn2+than other N species.Moreover,quasi-solid-state ZIHCs with gelatin based gel electrolytes exhibited high energy density of 157.6 Wh kg^-1 at 0.69 kW kg^-1,high safety and mechanical flexibility to withstand mechanical deformation and drilling.This strategy of developing pyridinic nitrogen enriched porous carbon will pave a new avenue to construct safe ZIHCs with high energy densities.     

Design of a micro-pattern structure for a three dimensionally macroporous Sn-Ni alloy anode with high areal capacity

A highly patterned porous Sn-Ni anode with various patterns was investigated as an anode for a lithium battery and showed much higher areal capacity than a conventional graphite electrode. This result proves the importance of a structured electrode for development of an electrode with higher performance.     

Facile fabrication of porous NiO films for lithium-ion batteries with high reversibility and rate capability

We report the high-rate capability and good cyclability of three-dimension nanoporous NiO films as the anodes of lithium-ion batteries. The NiO films are fabricated by immersing foam nickel substrates in an 80 °C aqueous solution containing ammonia and potassium peroxydisulfate, and subsequent heat treatment at 500 °C. At a rate of 1.0 C, the film electrodes maintain a capacity of 560 mAh g⁻¹ as well as capacity retention of 97% after 100 discharge/charge cycles. When the current density is increased to 14C, 42% of the capacity can be retained. Owing to the ease of large-scale fabrication and superior electrochemical performance, these NiO films will be promising anodes for high-energy-density lithium-ion batteries.     

Synthesis and characterization of Nano titania particles embedded in mesoporous silica with both high photocatalytic activity and adsorption capability

TiO(2)-xSiO(2) composites with a high specific surface area (up to 645 m(2)/g), large pore volume, and narrow distribution with average pore sizes ranging from 15 to 20 A have been synthesized by the sol-gel method. The results of characterization by XRD, BET, TEM, FTIR, and DRUV reveal that these TiO(2)-xSiO(2) composites exhibit a core/shell structure of a nano titania/Ti-O-Si species modified titania embedded in mesoporous silica. As compared to pure anatase, the embedding of nano titania particles into the mesoporous silica matrix results in a substantial blue shift of absorption edge from 3.2 to 3.54 eV and higher UV absorption intensity, which are attributed to the formation of the Ti-O-Si species modified titania in the interface between titania and silica. The as-synthesized TiO(2)-xSiO(2) composites exhibit both much higher absorption capability of organic pollutants and better photocatalytic activity for the photooxidation of benzene than pure titania. The better photocatalytic activity of as-synthesized TiO(2)-xSiO(2) composites than pure titania is attributed to their high surface area, higher UV absorption intensity, and easy diffusion of absorbed pollutants on the absorption sites to photogenerated oxidizing radicals on the photoactive sites.     

Magnetic impurity effects on self-discharge capacity,cycle performance,and rate capability of LiFePO4/C composites

Journal of Solid State Electrochemistry - Battery manufacturers pay a great deal of attention to the reproducibility of LiFePO4/C composites. Poor reproducibility of self-discharge capacity, cycle...     

Low-strain Co-free Li-rich layered cathode with excellent voltage and capacity stability

Owing to the inherent advantages of low cost and high capacity, cobalt(Co)-free lithium(Li)-rich layered oxides have become one of the most promising cathodes for next-generation high-energy lithium-ion batteries. However, these familial cathodes suffer from serious voltage decay due to many reasons, such as oxygen release and transition metal(TM) migration, which are closely related to nanoscale strain evolution. Here, by combining the synergistic effects of surface integration, bulk doping, an...     

Supercapacitor electrodes with especially high rate capability and cyclability based on a novel Pt nanosphere and cysteine-generated graphene

In the present work, supercapacitors based on graphene/Pt films show especially high rate capability (120 F g(-1) even at 50 A g(-1)) and cyclability (no attenuation over 10,000 cycles) and peculiar nanosphere morphology after electrochemical cycling. Furthermore, supercapacitors based on the graphene powder with a binder exhibit high specific capacitance (249 F g(-1) at 0.1 A g(-1)), long cycle life (no attenuation over 40,000 cycles) and high rate capability (150 F g(-1) even at 50 A g(-1)), which are much better than those of most graphene electrode materials. These indicate the great potential of the cysteine reduced graphene electrodes in energy storage.     

High rate capability and thermal stability of monoclinic-Li2MnSiO4 – A promising high capacity cathode material for lithium batteries

Journal of Solid State Electrochemistry - Li2MnSiO4 has attracted significant attention as cathode material for lithium ion batteries due to its structural diversity, abundance, low cost, thermal...     

Enhanced rate capability and mitigated capacity decay of ultrahigh-nickel cobalt-free LiNi0.9Mn0.1O2 cathode at high-voltage by selective tungsten substitution

Owing to the further requirement for electric vehicle market, it is appropriate to lower the cost and improve the energy density of lithium-ion batteries by adopting the Co-free and Ni-rich layered cathodes. However, their practical application is severely limited by structural instability and slow kinetics. Herein, ultrahigh-nickel cobalt-free LiNi_0.9Mn_0.1O₂ cathode is elaborate designed via in-situ trace substitution of tungsten by a wet co-precipitation method following by high-temperature sintering. It is revealed that the in-situ doping strategy of high valence W⁶⁺ can effectively improve the structure stability by reducing irreversible phase transition and suppressing the formation of microcracks. Moreover, the transformed fine particles determined by W-doping can facilitate the kinetic characteristics by shortening Li⁺ diffusion paths. As expected, 0.3 mol% W-doped LiNi_0.9Mn_0.1O₂ cathode exhibits a high specific capacity of 143.5 mAh/g after 200 cycles at high rate of 5 C in the wide potential range of 2.8-4.5 V, representing a potential next-generation cathode with low-cost, high energy-density and fast-charging capabilities.     

Simplified fabrication of high areal capacitance all-solid-state micro-supercapacitors based on graphene and MnO2 nanosheets

A universal simplified strategy was developed to fabricate all-solid-state planar micro-supercapacitors with high areal capacitance (~355 mF/cm²), based on interdigital patterned films of 2D pseudocapacitive MnO₂ nanosheets and electrochemically exfoliated graphene.     

A facile photo-induced synthesis of COOH functionalized meso-macroporous carbon films and their excellent sensing capability for aromatic amines

A simple photo-induced approach is developed for the preparation of COOH functionalized meso-macroporous carbon films with tunable pores without using any inorganic mesoporous silica templates, which show excellent sensing selectivity for aniline and the selectivity can be enhanced upon increasing COOH functional groups.     

High capacity and excellent cyclability of vanadium (IV) oxide in lithium battery applications

A VO₂ · 0.43H₂O powder with a flaky particle morphology was synthesized via a hydrothermal reduction method. It was characterized by scanning electron microscopy, electron energy loss spectroscopy, and thermogravimetric analysis. As an electrode material for rechargeable lithium batteries, it was used both as a cathode versus lithium anode and as an anode versus LiCoO₂, LiFePO₄ or LiNi_0.5Mn_1.5O₄ cathode. The VO₂ · 0.43H₂O electrode exhibits an extraordinary superiority with high capacity (160 mAh g^?1), high energy efficiency (95%), excellent cyclability (142.5 mAh g^?1 after 500 cycles) and rate capability (100 mAh g^?1 at 10 C-rate).