二次金属离子电池的研究现状

二次电池是应用范围广泛,发展前景广阔的电化学储能器件。综述了二次金属离子电池体系的基本工作原理和研究现状,对二次金属离子电池储能技术的发展做出了展望。

石墨炔在电化学储能器件中的应用

当今社会,电化学储能器件在人类的社会活动中变得越来越重要。电极材料作为电化学储能器件的核心部分,一直是人们研究的焦点。石墨炔是一种新型的二维平面结构的全碳材料,它宽的层间距、大的比表面积、独特的三维孔隙结构和好的导电性使其在能源存储器件电极材料应用中具有巨大的潜力。基于石墨炔温和的制备方法与独特的结构特征,本文详细介绍了近年来石墨炔在储能方面的理论分析和实验进展。通过研究锂/钠在单层、多层石墨炔上的迁移率和存储,理论分析石墨炔基电池具有很好的储锂储钠性能。实验方面,石墨炔作为电极材料在储钠储锂方面的容量与理论值相近。此外石墨炔作为电极材料成功应用于超级电容器和金属-硫电池,并表现出了优异的容量存储性能。石墨炔纳米形貌的调控、石墨炔的热处理,以及异原子的掺杂等均可以有效地提高石墨炔在这些储能器件中的性能。

Influence of Metal Sulfides as Anode Catalysts on Performance of H_2S SOFC

Two anode catalysts with Pt, MoS2 and composite metal sulfides (MoS2+NiS), are investigated for electrochemical oxidation of hydrogen sulfide in solid oxide fuel cell (SOFC) at temperatures 750-850℃. The catalysts comprising MoS2 and MoSa+NiS exhibited good electrical conductivity and catalytic activity. MoS2 and composite catalysts were found to be more active than Pt, a widely used catalyst for high temperature H2S/O2 fuel cell at 750-850℃. However, MoS2 itself sublimes above 450℃. In contrast, composite catalysts containing both Mo and transition metal (Ni) are shown to be stable and effective in promoting the oxidation of H2S in SOFC up to 850℃. However, electric contact is poor between the platinum current collecting layer and the composite metal sulfide layer, so that the cell performance becomes worse. This problem is overcome by adding conductive Ag powder into the anode layer (forming MoS2+NiS+Ag anode material) to increase anode electrical conductance instead of applying a thin layer of platinum on the top of anode.

Bifunctional polymer electrolyte with higher lithium-ion transference number for lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries have attracted enormous interest due to their super-high theoretical energy density(2600 W·h/kg)in recent years.However,issues such as lithium dendrites and the shuttle effect severely hampered the large-scale application of Li-S batteries.Herein,a novel bifunctional gel polymer electrolyte,poly(N,Ndiallyl-N,N-dimethylammonium bis(trifluoromethylsulfonylimide))-P(VDF-HFP)(PDDA-TFSI-P(VDF-HFP),PTP),was prepared by anion exchange reaction to tackle the above problems.Benefited from the interaction between TFSI-and quaternary ammonium ion in PTP,a higher lithium-ion transference number was obtained,which could availably protect Li metal anodes.Meanwhile,due to the adsorption interactions between PDDA-TFSI and polysulfides(LiPSs),the shuttle effect of Li-S batteries could be alleviated effectively.Consequently,the Li symmetric batteries assembled with PTP cycled more than 1000 h and lithium metal anodes were protected effectively.Li-S batteries assembled with this polymer electrolyte show a discharge specific capacity of 813 mA·h/g after 200 cycles and 467 mA·h/g at 3 C,exhibiting excellent cycling stability and C-rates performance.

Stable interphase chemistry of textured Zn anode for rechargeable aqueous batteries

Despite the advances of aqueous zinc(Zn)batteries as sustainable energy storage systems,their practical application remains challenging due to the issues of spontaneous corrosion and dendritic deposits at the Zn metal anode.In this work,conformal growth of zinc hydroxide sulfate(ZHS)with dominating(001)facet was realized on(002)plane-dominated Zn metal foil fabricated through a facile thermal annealing process.The ZHS possessed high Zn^(2+)conductivity(16.9 mS cm^(-1))and low electronic conductivity(1.28×10^(4)Ωcm),and acted as a heterogeneous and robust solid electrolyte interface(SEI)layer on metallic Zn electrode,which regulated the electrochemical Zn plating behavior and suppressed side reactions simultaneously.Moreover,low self-diffusion barrier along the(002)plane promoted the 2D diffusion and horizontal electrochemical plating of metallic Zn for(002)-textured Zn electrode.Consequently,the as-achieved Zn electrode exhibited remarkable cycling stability over 7000 cycles at 2 mA cm^(-2)and 0.5 mAh cm^(-2)with a low overpotential of 25 mV in symmetric cells.Pairing with a MnO_(2)cathode,the as-achieved Zn electrode achieved stable cell cycling with 92.7%capacity retention after 1000 cycles at 10 C with a remarkable average Coulombic efficiency of 99.9%.

LDHs derived nanoparticle-stacked metal nitride as interlayer for long-life lithium sulfur batteries

Shuttle effect is one of the most serious disadvantages in lithium-sulfur battery which results in poor cycle performance and hinders the commercialization of Li-S battery.To reduce the dissolution of polysulfides into the electrolyte and prolong the cycling stability,nanoparticle-stacked metal nitride derived from layered double hydroxides(LDHs)as an interlayer was inserted between sulfur cathode and separator to confine polysulfides by physical and chemical interactions.Meanwhile,the surface of metal nitride will form an oxide passivation layer.The passivation layer possesses hydrophilic metal-O group and provides a polar surface for strong binding with polysulfide.What’s more,the nanoparticlesstacked structure could immerge and retain electrolyte well,which could enhance the ability of promoting the electron exchange rate.The sulfur electrode with nanoparticle-stacked metal nitride interlayer has an excellent cycle performance owing to the interactions between metal nitride and polysulfides.The battery delivered an initial capacity of 764.6 m Ahg^(-1) and still possesses a capacity of 477.5 mAhg^(-1) with the retention of 62.4% after 800 cycles.

Recyclable cobalt-molybdenum bimetallic carbide modified separator boosts the polysulfide adsorption-catalysis of lithium sulfur battery

The polysulfide shuttling and sluggish redox kinetics,due to the notorious adsorption-catalysis underperformance,are the ultimate obstacles of the practical application of lithium-sulfur(Li-S)batteries.Conventional carbon-based and transition metal compound-based material solutions generally suffer from poor catalysis and adsorption,respectively,despite the performance gain in terms of the other.Herein,we have enhanced polysulfide adsorptioncatalytic capability and protected the Li anode using a complementary bimetallic carbide electrocatalyst,Co3 Mo3 C,modified commercial separator.With this demonstration,the potentials of bimetal compounds,which have been well recognized in other environmental catalysis,are also extended to Li-S batteries.Coupled with this modified separator,a simple cathode(S/Super P composite)can deliver high sulfur utilization,high rate performance,and excellent cycle stability with a low capacity decay rate of^0.034%per cycle at 1 C up to1000 cycles.Even at a high S-loading of 8.0 mg cm^-2 with electrolyte/sulfur ratio=6 m L g^-1,the cathode still exhibits high areal capacity of^6.8 m A h cm^-2.The experimental analysis and the first-principles calculations proved that the bimetallic carbide Co3 Mo3 C provides more binding sites for adsorbing polysulfides and catalyzing the multiphase conversion of sulfur/polysulfide/sulfide than monometallic carbide Mo2 C.Moreover,the modified separator can be reutilized with comparable electrochemical performance.We also showed other bimetallic carbides with similar catalytic effects on Li-S batteries and this material family has great promise indifferent energy electrocatalytic systems.