Cation-doped LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cathode with high rate performance

The nickel-rich layered cathode material LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)has high energy density,lower cost and is a promising cathode material currently under development.However,its electrochemical and structural stability is poor during cycling.Among the many modification methods,cation doping has been consistently proven to be an effective strategy for enhancing electrochemical performance.Herein,the NCM811 cathode material was modified by solid-phase reactions with Mg and Al doped.In addition,the corresponding mechanism of NCM811 cathode material-doped modification is explored by density functional theory(DFT)calculations,and we have extended this approach to other ternary cathode materials with different ratios and obtained universal laws.Combined with DFT calculations,the results show that Mg2+occupies the Li+site and reduces the degree of Li^(+)/Ni^(2+) mixture;Al^(3+) acts as a structural support during charging and discharging to prevent structural collapse.The electrochemical properties were tested by an electrochemical workstation and the LAND system,and the results showed that the capacity retention rate increased to varying degrees from 63.66%to 69.87%and 89.05%for NCM811-Mg and NCM811-Al at room temperature after 300 cycles,respectively.This study provides a theoretical basis and design strategy for commercializing cationic-doped modification of nickel-rich cathode materials.

Study on metal recovery process and kinetics of oxidative leaching from spent LiFePO_(4)Li-batteries

A green environmental protection and enhanced leaching process was proposed to recover all elements from spent lithium iron phosphate(LiFePO_(4)) lithium batteries.In order to reduce the influence of Al impurity in the recovery process,NaOH was used to remove impurity.After impurity removal,the spent LiFePO_(4) cathode material was used as raw material under the H_(2)SO_(4) system,and the pressure oxidation leaching process was adopted to achieve the preferential leaching of lithium.The E-pH diagram of the Fe-P-Al-H_(2)O system can determine the stable region of each element in the recovery process of spent LiFePO_(4)Li-batteries.Under the optimal conditions(500 r·min^(-1),15 h,363.15 K,0.4 MPa,the liquid-solid ratio was 4:1 ml·g^(-1)and the acid-material ratio was 0.29),the leaching rate of Li was 99.24%,Fe,Al,and Ti were 0.10%,2.07%,and 0.03%,respectively.The Fe and P were precipitated and recovered as FePO_(4)·2H_(2)O.The kinetic analysis shows that the process of high-pressure acid leaching of spent LiFePO_(4) materials depends on the surface chemical reaction.Through the life cycle assessment(LCA)of the spent LiFePO_(4) whole recovery process,eight midpoint impact categories were selected to assess the impact of recovery process.The results can provide basic environmental information on production process for recycling industry.

Separation of Pd and Pt from highly acidic leach liquor of spent automobile catalysts with monothio-Cyanex 272 and trioctylamine

Platinum group metals(PGMs),especially Pd,Pt,and Rh,have drawn great attention due to their unique features.Direct separation of Pd and Pt from highly acidic automobile catalyst leach liquors is disturbed by various factors.This work investigates the effect of various parameters including the acidity,extractant concentration,phase ratio A/O,and diluents on the Pd and Pt extraction and their stripping behaviors.The results show that the Pd and Pt are successfully separated from simulated leach liquor of spent automobile catalysts with monothioCyanex 272 and trioctylamine(TOA).Monothio-Cyanex 272 shows strong extractability and specific selectivity for Pd,and only one single stage is needed to recover more than 99.9% of Pd,leaving behind all the Pt,Rh,and base metals of Fe,Mg,Ce,Ni,Cu,and Co in the raffinate.The loaded Pd is efficiently stripped by acidic thiourea solutions.TOA shows strong extractability for Pt and Fe at acidity of 6 mol·L^(–1) HCl.More than 99.9% of Pt and all of the Fe are extracted into the organic phase after two stages of countercurrent extraction.Diluted HCl easily scrubs the loaded base metals(Fe,Cu,and Co).The loaded Pt is efficiently stripped by 1.0 mol·L^(–1) thiourea and 0.05–0.1 mol·L^(–1) Na OH solutions.Monothio-Cyanex 272 and TOA can realize the separation of Pd and Pt from highly acidic leach liquor of spent automobile catalysts.

Effects of Al and Co doping on the structural stability and high temperature cycling performance of LiNi_(0.5)Mn_(1.5)O_(4) spinel cathode materials

The poor structural stability and capacity retention of the high-voltage spinel-type LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)limits their further application.Herein,Al and Co were doped in LNMO materials for a more stable structure and capacity.The LNMO,LiNi_(0.45)Al_(0.05)Mn_(1.5)O_(4)(LNAMO)and LiNi_(0.45)Co_(0.05)Mn_(1.5)O_(4)(LNCMO)were synthesized by calcination at 900℃ for 8 h,which was called as solid-phase method and applied universally in industry.XRD,FT-IR and CV test results showed the synthesized samples have cation disordering Fd-3m space group structures.Moreover,the incorporation of Al and Co increased the cation disordering of LNMO,thereby increasing the transfer rate of Li+.The SEM results showed that the doped samples performed more regular and ortho-octahedral.The EDS elemental analysis confirmed the uniform distribution of each metal element in the samples.Moreover,the doped samples showed better electrochemical properties than undoped LNMO.The LNAMO and LNCMO samples were discharged with specific capacities of 116.3 mA·h·g^(-1)and 122.8 mA·h·g^(-1)at 1 C charge/discharge rate with good capacity retention of 95.8% and 94.8% after 200 cycles at room temperature,respectively.The capacity fading phenomenon of the doped samples at 50℃ and 1 C rate was significantly improved.Further,cations doping also enhanced the rate performance,especially for the LNCMO,the discharge specific capacity of 117.9 mA·h·g^(-1)can be obtained at a rate of 5 C.

Facile synthesis of spinel LiNi_(0.5)Mn_(1.5)O_(4) as 5.0 V-class high-voltage cathode materials for Li-ion batteries

LiNi_(0.5)Mn_(1.5)O_(4) and LiMn_(2)O_(4) with novel spinel morphology were synthesized by a hydrothermal and postcalcination process.The synthesized LiMn_(2)O_(4) particles(5–10 lm)are uniform hexahedron,while the LiNi_(0.5)Mn_(1.5)O_(4) has spindle-like morphology with the long axis 10–15 lm,short axis 5–8 lm.Both LiMn_(2)O_(4) and LiNi_(0.5)Mn_(1.5)O_(4) show high capacity when used as cathode materials for Li-ion batteries.In the voltage range of 2.5–5.5 V at room temperature,the LiNi_(0.5)Mn_(1.5)O_(4) has a high discharge capacity of 135.04 mA·h·g^(-1) at 20 mAg^(-1),which is close to 147 mA·h·g^(-1)(theoretical capacity of LiNi_(0.5)Mn_(1.5)O_(4)).The discharge capacity of LiMn_(2)O_(4) is 131.08 mA·h·g^(-1) at 20 mAg^(-1).Moreover,the LiNi_(0.5)Mn_(1.5)O_(4) shows a higher capacity retention(76%)compared to that of LiMn_(2)O_(4)(61%)after 50 cycles.The morphology and structure of LiMn_(2)O_(4) and LiNi_(0.5)Mn_(1.5)O_(4) are well kept even after cycling as demonstrated by SEM and XRD on cycled LiMn_(2)O_(4) and LiNi_(0.5)Mn_(1.5)O_(4) electrodes.

Amorphous Sn modified nitrogen-doped porous carbon nanosheets with rapid capacitive mechanism for highcapacity and fast-charging lithium-ion batteries

Sn-based materials are considered as a kind of potential anode materials for lithium-ion batteries(LIBs)owing to their high theoretical capacity.However,their use is limited by large volume expansion deriving from the lithiation/delithiation process.In this work,amorphous Sn modified nitrogen-doped porous carbon nanosheets(ASnNPCNs)are obtained.The synergistic effect of amorphous Sn and high edge-nitrogendoped level porous carbon nanosheets provides ASn-NPCNs with multiple advantages containing abundant defect sites,high specific surface area(214.9 m^(2)·g^(−1)),and rich hierarchical pores,which can promote the lithium-ion storage.Serving as the LIB anode,the as-prepared ASn-NPCNs-750 electrode exhibits an ultrahigh capacity of 1643 mAh·g^(−1) at 0.1 A·g^(−1),ultrafast rate performance of 490 mAh·g^(−1) at 10 A·g^(−1),and superior long-term cycling performance of 988 mAh·g^(−1) at 1 A·g^(−1) after 2000 cycles with a capacity retention of 98.9%.Furthermore,the in-depth electrochemical kinetic test confirms that the ultrahigh-capacity and fast-charging performance of the ASn-NPCNs750 electrode is ascribed to the rapid capacitive mechanism.These impressive results indicate that ASn-NPCNs-750 can be a potential anode material for high-capacity and fast-charging LIBs.

锂离子电池高压电解液

锂离子电池作为一种绿色可充电电池,具有较高能量密度以及功率密度,是便携式电子产品的首选,并逐渐应用于动力汽车领域。为了更好地满足其应用需求,需要进一步提高当前锂离子电池的能量密度。不同于高压正极材料的快速发展,传统电解液在较高工作电压下容易分解,很大程度上阻碍了高能量密度锂离子电池的商业化应用。作为锂离子电池的重要组分,电解液对其多方面性能均具有重要影响,因此亟需提高电解液的工作电压以解决锂离子电池能量密度较低的问题。本文从新型有机溶剂以及高电压添加剂两方面入手,综述近年来国内外高压电解液的研究进展,介绍理论计算对于设计高压电解液的作用,并对高压电解液的发展及前景做出总结和展望。

Contributions of root cell wall polysaccharides to Cu sequestration in castor(Ricinus communis L.)exposed to different Cu stresses

Cell wall polysaccharides play a vital role in binding with toxic metals such as copper(Cu)ions.However, it is still unclear whether the major binding site of Cu in the cell wall varies with different degrees of Cu stresses.Moreover, the contribution of each cell wall polysaccharide fraction to Cu sequestration with different degrees of Cu stresses also remains to be verified.The distribution of Cu in cell wall polysaccharide fractions of castor(Ricinus communis L.) root was investigated with various Cu concentrations in the hydroponic experiment.The results showed that the hemicellulose1(HC1) fraction fixed 44.9%–67.8% of the total cell wall Cu under Cu stress.In addition, the pectin fraction and hemicelluloses2(HC2) fraction also contributed to the Cu binding in root cell wall,accounting for 11.0%–25.9% and 14.1%–26.6% of the total cell wall Cu under Cu treatments, respectively.When the Cu levels were ≤ 25 μmol/L, pectin and HC2 contributed equally to Cu storage in root cell wall.However, when the Cu level was higher than 25 μmol/L, the ability of the pectin to bind Cu was easy to reach saturation.Much more Cu ions were bound on HC1 and HC2 fractions, and the HC2 played a much more important role in Cu binding than pectin.Combining fourier transform infrared(FT-IR) and twodimensional correlation analysis(2 D-COS) techniques, the hemicellulose components were showed not only to accumulate most of Cu in cell wall, but also respond fastest to Cu stress.

In vitro metabolism and inhibitory effects of atractylenolideⅡon various hepatic CYPs in HLMs

In the present study,we aimed to investigate the interaction between atractylenolideⅡ(AT-Ⅱ)and CYP450 enzyme in human liver microsomes,and to lay a theoretical foundation for predicting the possible interaction of AT-Ⅱin combination with drugs.The chemical inhibition experiment was carried out with specific inhibitors to clarify the CYP450 subtypes affecting the metabolism of AT-Ⅱ,and the mechanism,kinetics,and type of inhibition of CYP450 enzyme by AT-Ⅱwere studied by using the probe-based determination method of human liver microsome system with the related data of IC50 and Ki as evaluation indexes.The metabolism of AT-Ⅱwas affected by CYP1A2,CYP2C9 and CYP3A4 inhibitors,and the highest inhibition rates were41.35%,41.97%and 82.45%,respectively.The IC50 values of AT-Ⅱto five subtypes of P450 CYP2C9,CYP1A2,CYP2C19,CYP3A4 and CYP2D6 were 69.7,84.3,92.4,173.8 and 190.1μmol/L,respectively.The Ki values of AT-Ⅱto five subtypes of P450 CYP2C9,CYP1A2,CYP2C19,CYP3A4 and CYP2D6 were 190.6,179.1,>200,72.2 and 66.8,respectively.Among these enzymes,AT-Ⅱexhibited non-competitive inhibition on CYP1A2,showed competitive inhibition on CYP2C9 and CYP3A4,and displayed mixed AT-Ⅱinhibition on CYP2C19 and CYP2D6.CYP1A2,CYP2C9 and CYP3A4 were involved in the AT-Ⅱmetabolism,and AT-Ⅱexhibited different inhibitory mechanisms and strengths for the five subtypes of CYP450.

Template-mediated strategy to regulate hierarchically nitrogen-sulfur co-doped porous carbon as superior anode material for lithium capacity

Considering its rapid lithiation/delithiation process and robust capacitive energy storage,hierarchical porous carbon is regarded as a promising candidate for lithium-ion batteries(LIBs).However,it remains a great challenge to construct a porous structure and prevent structure stacking for carbon-based materials.Herein,a templatemediated approach is developed to synthesize hierarchical nitrogen-sulfur co-doped porous carbon(NSPC)using low-cost asphalt precursors.The strategy for synthesis uses g-C_(3)N_(4) and NaHCO_(3) as gaseous templates and NaCl as a solid template,which causes the formation of hierarchical porous carbon with a high specific surface area.The resultant porous structure and nitrogen-doping process can prevent the aggregation of nanosheets,maintain the structural stability upon cycling,and achieve rate-capable lithium storage.Serving as a LIBs anode,reversible specific capacities of the NSPC24 electrode reach 788 and 280 mAh·g^(-1) at 0.1 and 1 A·g^(-1),respectively.Furthermore,its specific capacity remains at 830 mAh·g^(-1) after 115 cycles at 0.1 A·g^(-1).Even after 500 cycles,high specific capacities of 727 mAh·g^(-1) at 0.5 A·g^(-1) and 624 mAh·g^(-1) at 1 A·g^(-1) are achieved,demonstrating excellent cycling performance.The gas-solid bifunctional template-mediated approach can guide the design of porous materials very well,meanwhile realizing the high value-added utilization of asphalt.

Porous carbon spheres anode with the stable output of low delithiation plateau and constant delithiation ratio for lithium ion hybrid capacitor

Porous carbon spheres derived from the facile hydrothermal treatment associated with the calcination process exhibit the good spherical morphology and unique porous structure.For the Li-based half-cell test,porous carbon spheres electrode not only exhibits larger reversible capacities and better compatibility as compared to the widely-used graphite,but also provides stable delithiation plateaus under different current density.Additionally,the delithiation ratio below 1 V almost accounts for a constant value(around 70%)with the increase of current density,evidencing that Li intercalation storage is the dominant model and Li insertion/extraction processes are propitious.The lithium ion hybrid capacitor configured with S-doped mesoporous graphene and porous carbon spheres as cathode and anode,delivers satisfied energy and power densities(up to 177 Wh kg^(−1) and 12,303 W kg^(−1),respectively)as well as long-term cyclability,which is superior to the corresponding S-doped mesoporous graphene//graphite and activated carbon//porous carbon spheres.In addition,the developed synthesis strategy is in favor of the realization of the scalable production of porous carbon spheres.