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The recycling of spent lithium-ion batteries (LIBs) is an effectual strategy for mitigating environmental and resource crises. Lithium iron phosphate batteries, renowned for their unique safety and stability, are widely utilized in energy storage systems and electric vehicles, consequently resulting in a growing number of spent LIBs. Herein, a one-pot mechanochemical process that integrates the recycling and preparation of LiFePO4 is proposed to drive the rapid regeneration of spent LiFePO4. Benefiting from the inherent characteristics of the input material, more than 98% of Li is selectively released, while less than 1.5% of Fe is leached without any impurity output. To this end, these reclaimed precursors in a ball mill can be directly re-used for the regeneration of LiFePO4 with an appropriate lithium source addition, eliminating the need to recover LiFePO4 with various degrees of lithium deficiency. As expected, the regenerated LiFePO4 delivers a discharge specific capacity of 143 mA h g−1 without negligible capacity fading after 250 cycles at 1 C, featuring significantly improved rate capability and long-term cycling stability. Designed with sustainable, integrated, and close-loop operation routes, this process pioneers a novel strategy to scale up the direct recycling for the LiFePO4 cathode. [ABSTRACT FROM AUTHOR]

Compared with monometallic selenides, bimetallic selenides have better synergistic effects and more abundant active sites for electrochemical reactions. As an important member of the transition metal oxide family, NiCoSe2 has been widely used in energy storage devices and has shown excellent electrochemical performance. So in this paper, nitrogen-doped carbon decorated NiCoSe2 composites (NiCoSe2/NC-700, NiCoSe2/NC-800, and NiCoSe2/NC-900) with a microflower structure were synthesized by calcining nickel–cobalt bimetallic organic skeleton materials at different temperatures, and were used as anode materials for rechargeable lithium-ion batteries. Because the MOF precursor has many advantages such as structural controllability, and a bimetal synergistic effect, the test results showed that the prepared NiCoSe2/NC composites have a special morphology, outstanding electrical conductivity, excellent lithium storage performance and electrochemical cycling performance in the process of being used as anode materials for lithium-ion batteries. The NiCoSe2/NC-800 materials displayed a high initial capacity (2099.8/1084.3 mA h g−1), and still maintained a high capacity (1041.2/989.9 mA h g−1) after 100 cycles at a current density of 0.1 A g−1 and in the voltage range of 0.01–3.0 V. In addition, at high current densities of 0.5 A g−1 and 1.0 A g−1, the increased capacity of NiCoSe2/NC composites may be due to the activation of electrodes and the pseudocapacitance during cycling. Through ex situ XRD experiments, the lithium storage mechanism of the NiCoSe2/NC-800 electrode material during cycling was further studied, and NiCoSe2/NC-800 was continuously converted into Ni, Co, and Li2Se during cycling. [ABSTRACT FROM AUTHOR]

A new flexible aromatic polymer sulfonated polybenzothiazole (sPBT-SE) with sulphone and ether units is reported as an advanced cathode material for storing Na+, which delivers a high discharge capacity of 103 mA h g−1 after 350 cycles at 30 mA g−1. [ABSTRACT FROM AUTHOR]

The recycling of spent lithium-ion batteries (LIBs) is a crucial issue that has engaged extensive attention worldwide, along with the rapidly increasing usage of lithium-ion batteries. State-of-art recycling approaches, in terms of chemical leaching, have imperfections such as excessive chemical consumption, tedious recycling procedure and aggravated secondary pollution. In this research, a green and closed-loop route for the recycling of spent LiFePO4 involving oxidation leaching is demonstrated. By properly adjusting or controlling the leaching parameters, the leaching efficiency of lithium is up to 97.6% with the introduction of hydrogen peroxide, which is facilitated to achieve the transformed high-purity lithium carbonate and iron phosphate. The oxidation reaction mechanisms are clarified through thermodynamic and kinetic analyses, which identified that the oxidation leaching reaction is co-controlled by the internal diffusion and chemical reaction. Consequently, LiFePO4 cathode materials are regenerated by utilizing the obtained raw materials, as expected, which deliver superior cycling stability with less than 1% of capacity loss after 300 cycles and excellent rate performances. This research embodies the possibility of efficient recycling of LiFePO4 from spent lithium-ion batteries based on the principles of green chemistry that is possibly committed to the sustainability of the lithium-ion battery industry. [ABSTRACT FROM AUTHOR]

Due to its high theoretical capacity (∼280 mA h g−1), lithium vanadium oxide (LiV3O8) is considered a promising electrode material for meeting the demands for a longer battery life. However, it still suffers from an inferior cycling stability and rate properties. Benefitting from the unique traits of rare earth metal La, La-doping was introduced to V-sites, leading to an expansion of the lattice volume and reduced particle size, and bringing about more oxygen defects for fast ion redox reactions. The considerable discharge capacity of optimized La-doped LiV3O8 could reach up to 308 mA h g−1, and the capacity could be kept at 252 mA h g−1 after numerous loops. Supported by a detailed analysis of the capacity curves, an improved redox activity of V5+ was strongly demonstrated. Moreover, compared to the basic materials, an increasing rate capacity located in the low potential range was detected, ascribed to the existence of an oxygen vacancy, enabling a reduction in the energy barrier and a broadening of the energy distribution. Interestingly, La-doping could ultimately improve the capacity and is thus worth further exploration, particularly for the design of advanced cathodic materials. [ABSTRACT FROM AUTHOR]

Cycloaddition reactions of carbynes in metallacycles with π-bond substrates have been rarely reported. We report the first [2+2] cycloaddition of metallapentalynes with nitrosoarenes to obtain the first metallapentalenoxazetes, and their photophysical and electrochemical properties were studied by UV-Vis spectroscopy and cyclic voltammetry with the help of theoretical calculations. [ABSTRACT FROM AUTHOR]

We constructed a series of novel chiral molecular face-rotating polyhedra (FRP) from two 10,15-dihydro-5H-diindolo[3,2-a:3′,2′-c]carbazole (triazatruxene) derivatives and trans-1,2-cyclohexane diamine, and investigated how facial interactions and the positions of substituents determine the diastereoselectivity and geometry of the final assemblies. [ABSTRACT FROM AUTHOR]

Restricted by their high specific surface area and porous structures, activated carbon (AC) materials display poor performances, such as a low initial coulombic efficiency in sodium-ion batteries (SIBs). Nevertheless, it is an ideal choice for carriers, where the high specific surface area is indispensable. Herein, a novel strategy to design S-doped carbon employing durian shell-based AC (DSAC) as the template is proposed and the effect of the amount of DSAC additive was investigated in detail. Impressively, an optimized amount of DSAC additive would contribute to the good dispersion of poly-2-thiophenemethanol (sulfur source) as well as an increased number of active sites for Na storage, thus resulting in excellent electrochemical performance. A high reversible specific capacity of 345 mA h g−1 was attained and the specific capacity of 264 mA h g−1 was retained after 200 cycles. In particular, a high initial coulombic efficiency of 56.02% and remarkable rate capability of 100.02 mA h g−1 were achieved at 5 A g−1 even after 4500 cycles. Meaningfully, the proposed route used to prepare carbon materials for SIBs can effectively facilitate the further application of AC and the construction of high-performance electrode materials for SIBs. [ABSTRACT FROM AUTHOR]

We report the post-synthesis interconversion of two enantiomeric organic cages through turning inside out. By scrutinizing the thermodynamics and kinetics, we are able to control the racemization rate by various reaction conditions and reveal that the turning-inside-out interconversion is realized through a partial disassembly pathway. The kinetics investigation also provides insight into the dynamic essence of imine chemistry using different solvents and catalysts. [ABSTRACT FROM AUTHOR]

Hollow-sphere ZnSe is successfully obtained through Ostwald ripening. Carbon nanoparticles are designed and utilized to form a wrapped carbon network as a conductive buffering matrix by subsequent annealing. The ZnSe/C composites, as anode materials for lithium-ion batteries (LIBs), exhibit excellent Li+ storage properties, delivering a high reversible capacity of 573.7 mA h g−1 at 1.0 A g−1 after 800 cycles. Even upon increasing the high current density to 20.0 A g−1, the reversible capacity can achieve 318.8 mA h g−1 after 5000 cycles. The superior rate capability is confirmed through the current density return from 20.0 to 1.0 A g−1, and ZnSe/C composites still recover up to 469 mA h g−1, with a retention of 92%. The enhanced electrochemical performances of ZnSe/C composites are attributed to the unique structure and the introduction of conductive carbon networks, which can improve the Li+ diffusion coefficient in the insertion and extraction process. Furthermore, the interconnected network also alleviates the volume variation during cycling and further enhances the structural stability. [ABSTRACT FROM AUTHOR]

Excellent C-rate and cycling performance with a high specific capacity of 117.6 mA h g−1 have been achieved on NASICON-structure Na3V2(PO4)3 sodium-ion batteries. Two different Na sites, namely Na(1) and Na(2), are reported in the open three-dimensional framework, of which the ions at the Na(2) sites should be mainly responsible for the electrochemical properties. It is vitally important and interesting to find that there are two kinds of possible ion occupation of Na ions in Na3V2(PO4)3 and the investigation of ion-extraction number is firstly explored by discussing ion occupations with the help of first-principles calculations. The ion occupation of 0.75 for all Na sites is suitable for the configuration of [Na3V2(PO4)3]2, and the two-step extraction process accompanied by structure reorganization can account for the theoretical capacity of Na3V2(PO4)3. [ABSTRACT FROM AUTHOR]

Compared with monometallic selenides, bimetallic selenides have better synergistic effects and more abundant active sites for electrochemical reactions. As an important member of the transition metal oxide family, NiCoSe 2 has been widely used in energy storage devices and has shown excellent electrochemical performance. So in this paper, nitrogen-doped carbon decorated NiCoSe 2 composites (NiCoSe 2 /NC-700, NiCoSe 2 /NC-800, and NiCoSe 2 /NC-900) with a microflower structure were synthesized by calcining nickel-cobalt bimetallic organic skeleton materials at different temperatures, and were used as anode materials for rechargeable lithium-ion batteries. Because the MOF precursor has many advantages such as structural controllability, and a bimetal synergistic effect, the test results showed that the prepared NiCoSe 2 /NC composites have a special morphology, outstanding electrical conductivity, excellent lithium storage performance and electrochemical cycling performance in the process of being used as anode materials for lithium-ion batteries. The NiCoSe 2 /NC-800 materials displayed a high initial capacity (2099.8/1084.3 mA h g -1 ), and still maintained a high capacity (1041.2/989.9 mA h g -1 ) after 100 cycles at a current density of 0.1 A g -1 and in the voltage range of 0.01-3.0 V. In addition, at high current densities of 0.5 A g -1 and 1.0 A g -1 , the increased capacity of NiCoSe 2 /NC composites may be due to the activation of electrodes and the pseudocapacitance during cycling. Through ex situ XRD experiments, the lithium storage mechanism of the NiCoSe 2 /NC-800 electrode material during cycling was further studied, and NiCoSe 2 /NC-800 was continuously converted into Ni, Co, and Li 2 Se during cycling.

We report a facile atmospheric plasma reaction synthesis of Pt x Fe 1- x alloys with the different Pt/Fe stoichiometric ratio in Pt x Fe 1- x alloys on graphene (G) as efficient counter electrode (CE) materials and atmospheric plasma reaction synthesised TiO 2 nanoparticles/G as photoanode in dye-sensitized solar cells (DSSCs). Well-distributed Pt x Fe 1- x nanoparticles or TiO 2 nanoparticles on the G surface were obtained. Remarkably, DSSCs prepared by the Pt 0.7 Fe 0.3 /G CE have much higher catalytic activity and stable durability than Pt 1 Fe 0 /G CE. The as-synthesized Pt 0.7 Fe 0.3 /G CE exhibits the largest value of | J red | = 1.479 mA and the lowest value of R ct = 2.86 Ω. With the Pt 0.7 Fe 0.3 /G as CE and TiO 2 /G as the photoanode, the DSSC can deliver an overall power conversion efficiency (PCE) of 10.13%, which is significantly higher than the 9.72% of the expensive Pt 1 Fe 0 /G counterpart. The obtained results indicate that the Pt x Fe 1- x /G nanohybrids fabricated using atmospheric plasma reaction exhibited potential as a reference for next generation CE materials in highly efficient DSSCs. We believe that this work provides an effective strategy for optimizing Pt utilization for the low-cost and efficient application of DSSCs., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

To reduce the cost of CO 2 capture, polyethylene polyamine (PEPA), with a high amino density and relatively low price, was loaded into MCM-41 to prepare solid sorbents for CO 2 capture from flue gases. In addition, methoxypolyethylene glycol (MPEG) was codispersed and coimpregnated with PEPA to prepare composite sorbents. The pore structures, surface functional groups, adsorption and regeneration properties for the sorbents were measured and characterized. When CO 2 concentration is 15%, for 30, 40 and 50 wt% PEPA-loaded MCM-41, the equilibrium adsorption capacities were respectively determined to be 1.15, 1.47 and 1.66 mmol g -1 at 60 °C; for 30 wt% PEPA and 20 wt% MPEG, 40 wt% PEPA and 10 wt% MPEG, and 50 wt% PEPA and 5 wt% MPEG codispersed MCM-41, the equilibrium adsorption capacities were respectively determined to be 1.97, 2.22 and 2.25 mmol g -1 at 60 °C; the breakthrough and equilibrium adsorption capacities for 50 wt% PEPA and 5 wt% MPEG codispersed MCM-41 respectively reached 2.01 and 2.39 mmol g -1 at 50 °C, all values showed a significant increase compared to PEPA-modified MCM-41. After 10 regenerations, the equilibrium adsorption capacity for codispersed MCM-41 was reduced by 5.0%, with the regeneration performance being better than that of PEPA-loaded MCM-41, which was reduced by 7.8%. The CO 2 -TPD results indicated that the mutual interactions between PEPA and MPEG might change basic sites in MCM-41, thereby facilitating active site exposure and CO 2 adsorption., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Narcissistic chiral self-sorting prevailed in the assembly of molecular face-rotating polyhedra from a C 3h building block 5,5,10,10,15,15-hexabutyl-truxene-2,7,12-tricarbaldehyde and racemic mixtures of 1,2-diamines. Out of 124 possible stereoisomers, a pair of racemic polyhedra dominated, wherein (1R,2R)-diamines were segregated in AAAA polyhedra and (1S,2S)-diamines in CCCC polyhedra. This chiral self-sorting process is regulated by facial non-covalent interactions in the polyhedra. In contrast, D 3h facial building blocks 1,3,5-tris-(4-formyl-phenyl)triazine and racemic mixtures of 1,2-diamines assembled into polyhedra without facial interactions, and their assembly process did not undergo apparent chiral self-sorting.

Excellent C-rate and cycling performance with a high specific capacity of 117.6 mA h g(-1) have been achieved on NASICON-structure Na3V2(PO4)3 sodium-ion batteries. Two different Na sites, namely Na(1) and Na(2), are reported in the open three-dimensional framework, of which the ions at the Na(2) sites should be mainly responsible for the electrochemical properties. It is vitally important and interesting to find that there are two kinds of possible ion occupation of Na ions in Na3V2(PO4)3 and the investigation of ion-extraction number is firstly explored by discussing ion occupations with the help of first-principles calculations. The ion occupation of 0.75 for all Na sites is suitable for the configuration of [Na3V2(PO4)3]2, and the two-step extraction process accompanied by structure reorganization can account for the theoretical capacity of Na3V2(PO4)3.

NiSb alloy hollow nanospheres (HNSs) obtained by galvanic replacement were firstly applied as anode materials for lithium ion batteries, giving the best electrochemical performances for NiSb alloy materials so far with a high reversible capacity of 420 mA h g(-1) after 50 cycles, close to its theoretical capacity (446 mA h g(-1)).