Incorporating multifunctional LiAlSiO_(4) into polyethylene oxide for high-performance solid-state lithium batteries

High ionic conductivity,good electrochemical stability,and satisfactory mechanical property are the crucial factors for polymer solid state electrolytes.Herein,fast ion conductor LiAlSiO_4(LASO) is incorporated into polyethylene oxide(PEO)-based solid-state electrolytes(SSEs).The SSEs containing LASO exhibit enhanced mechanical properties performance compared to pristine PEO-LiTFSI electrolyte.A reduced melting transition temperature of 40.57℃ is enabled by introducing LASO in to PEO-based SSE,which is beneficial to the motion of PEO chain and makes it possible for working at a moderate environment.Coupling with the enhanced motion of PEO,dissociation of the lithium salt,and conducting channel of LASO,the optimized composite polymer SSE exhibits a high ionic conductivity of 4.68×10^(-4),3.16×10^(-4) and 1.62×10^(-4) S cm^(-1) at 60,50 and 40℃,respectively.The corresponding LiFePO_4//Li solid-state battery exhibits high specific capacities of 166,160 and 139 mAh g^(-1) at 0.2 C under 60,40 and 25℃.In addition,it remains 130 mAh g^(-1) at 4.0 C,and maintains 91.74% after 500 cycles at 1.0 C under 60℃.This study provides a simple approach for developing ionic conductor-filled polymer electrolytes in solid-state lithium battery application.

Recent advancements in hydrometallurgical recycling technologies of spent lithium-ion battery cathode materials

The rapidly increasing production of lithium-ion batteries(LIBs)and their limited service time increases the number of spent LIBs,eventually causing serious environmental issues and resource wastage.From the perspectives of clean production and the development of the LIB industry,the effective recovery and recycling of spent LIBs require urgent solutions.This study provides an overview of the current hydrometallurgical processes employed in the recycling of spent cathode materials,focusing on the leaching of valuable metals and their postprocessing.In particular,this research reviews the various leaching systems(inorganic acid,organic acid,and ammonia)and the separation of valuable metals,and then,recommendations for subsequent study are offered in an attempt to contribute to the development of highly efficient methods for recycling spent cathode materials.In addition,a range of existing technologies,such as solvent extraction,chemical precipitation,electrochemical deposition,and regeneration,for the postprocessing of leaching solutions are summarized.Finally,the promising technologies,existing challenges and suggestions with respect to the development of effective and environmentally friendly recycling methods for handling spent cathode materials are identified.

Electrocatalytic performance of CNTs/graphene composited rare earth phthalocyanines(M=La,Y,Yb,Sc)

In this study,a class of rare earth composite sandwich phthalocyanines(MPcs,M=La,Y,Yb,Sc) were prepared and compounded with graphene and carbon nanotubes to obtain MPc/Gr and MPc/CNTs composites.The electrocatalytic behaviors of MPc/Gr and MPc/CNTs electrodes were further investigated.The results show that the central rare earth metal has a large influence on the electrocatalytic performance.For the MPcs/Gr samples,ScPc with the smallest ionic radius and molecular size can be more uniformly dispersed in graphene,and the hydrogen precipitation overpotential of ScPc/Gr electrode is514 mV,corresponding to a Tafel slope of 148 mV/dec,with better electrocatalytic performance than other rare earth metal phthalocyanines.As for the MPc/CNTs composites,LaPc,which has the largest ionic radius and molecular size,is more uniformly dispersed on the surface of CNTs,so that the LaPc/CNT electrode exhibits the best LSV performance with the smallest corresponding Tafel slope(176 mV/dec).The main reason is the different binding modes of MPcs molecules in Gr and CNTs.When rare earth phthalocyanine is combined with layered graphene,the smallest size of rare earth phthalocyanine(ScPc)is more easily embedded in the graphene layer,resulting in better homogeneity of the composite,larger effective contact area and better electrocatalytic performance.In contrast,when rare earth phthalocyanine is bound to carbon nanotubes in a tubular structure,it is mainly bound by attaching to the surface or being entangled by the carbon nanotubes.In this case,the rare-earth phthalocyanine molecules(LaPc)with larger layer spacing can provide more contact area with CNTs,forming a more uniform and effective composite,which eventually provides more active sites and better electrocatalytic performance.

High-performance of sodium carboxylate-derived materials for electrochemical energy storage

Four types of sustainable sodium carboxylate- derived materials are investigated as novel electrodes with high performance for lithium-ion batteries. Benefiting from the porous morphology provided by their intermolecular in- teractions, increasing capacity, excellent cycle stability and superior rate performance are observed for the sodium car- boxylate-derived materials. The sodium oxalate （SO） electro- des displayed an increasing discharging capacity at a current density of 50 mA g-1 with maximum values of 242.9 mA h g-1 for SO-631 and 373.9 mA h g-1 for SO-541 during the 100th cycle. In addition, the SO-541, SC-541 （sodium citrate）, ST- 541 （sodium tartrate） and SP-541 （sodium pyromellitate） electrode materials displayed high initial capacities of 619.6-392.3, 403.7 and 278.1 mA h g-1, respectively, with capacity retentions of 179%, 148%, 173% and 108%, respectively, after 200 cycles at 50 mA g-1. Even at a high current density of 2,000 mA g-1, the capacities remain 157.6, 131.3, 146.6 and 137.0mAhg-1, respectively. With these superior electro- chemical properties, the sodium carboxylate-derived materials could be considered as promising organic electrode materials for large-scale sustainable lithium-ion batteries.

Constructing oxygen-deficient V_(2)O_(3)@C nanospheres for high performance potassium ion batteries

Potassium ion batteries(PIBs) have been regarded as promising alternatives to lithium ion batteries(LIBs)on account of their abundant resource and low cost in large scale energy storage applications. However,it still remains great challenges to explore suitable electrode materials that can reversibly accommodate large size of potassium ions. Here, we construct oxygen-deficient V_(2)O_(3)nanoparticles encapsulated in amorphous carbon shell(Od-V_(2)O_(3)@C) as anode materials for PIBs by subtly combining the strategies of morphology and deficiency engineering. The MOF derived nanostructure along with uniform carbon coating layer can not only enables fast K+migration and charge transfer kinetics, but also accommodate volume change and maintain structural stability. Besides, the introduction of oxygen deficiency intrinsically tunes the electronic structure of materials according to DFT calculation, and thus lead to improved electrochemical performance. When utilized as anode for PIBs, Od-V_(2)O_(3)@C electrode exhibits superior rate capability(reversible capacities of 262.8, 227.8, 201.5, 179.8, 156.9 mAh/g at 100, 200, 500, 1000 and2000 mA/g, respectively), and ultralong cycle life(127.4 mAh/g after 1000 cycles at 2 A/g). This study demonstrates a feasible way to realize high performance PIBs through morphology and deficiency engineering.

Construction of a novel ZnCo_2O_4/Bi_2O_3 heterojunction photocatalyst with enhanced visible light photocatalytic activity

A novel ZnCo_2O_4/Bi_2O_3 heterojunction photocatalyst was prepared, and the formation of the heterojunction was confirmed via HRTEM. Photocatalytic activity of as-prepared samples was evaluated through photodegradation of malachite green(MG). The degradation results show that the as-prepared13% ZnCo_2O_4/Bi_2O_3 heterojunction photocatalyst exhibits higher activity than pure Bi_2O_3. The MG degradation rate for the as-prepared catalyst is as high as 94%. The enhanced photocatalytic activity is mainly attributed to the broad photoabsorption and low recombination rate of photogenerated electronhole pairs, which is driven by the photogene rated potential difference formed at the ZnCo_2O_4/Bi_2O_3 heterojunction interface.

Al4B2O9 nanorods-modified solid polymer electrolytes with decent integrated performance

With the proliferation of energy storage and power applications, electric vehicles particularly, solid-state batteries are considered as one of the most promising strategies to address the ever-increasing safety concern and high energy demand of power devices. Here, we demonstrate the Al4B2O9 nanorods-modified poly(ethylene oxide) (PEO)-based solid polymer electrolyte (ASPE) with high ionic conductivity, wide electrochemical window, decent mechanical property and nonflammable performance. Specifically, because of the longer-range ordered Li+ transfer channels conducted by the interaction between Al4B2O9 nanorods and PEO, the optimal ASPE (ASPE-1) shows excellent ionic conductivity of 4.35×10^−1 and 3.1×10^−1 S cm^−1 at 30 and 60℃, respectively. It also has good electrochemical stability at 60℃ with a decomposition voltage of 5.1 V. Besides, the assembled LiFePO4//Li cells show good cycling performance, delivering 155 mA h g−1 after 300 cycles at 1 C under 60℃, and present excellent low temperature adaptability, retaining over 125 mA h g^−1 after 90 cycles at 0.2 C under 30℃. These results verify that the addition of Al4B2O9 nanorods can effectively promote the integrated performance of solid polymer electrolyte.