Lithium-ion batteries have been widely deployed in the electric vehicle sector, as well as in other application areas. This widespread use has led to the accumulation of large quantities of diverse spent batteries, particularly lithium iron phosphate (LFP), and the recycling of spent batteries is increasingly imperative. Considering the high economic value of the regenerated lithium manganese iron phosphate (LMFP) product and the coexistence of spent LFP and spent lithium manganate oxide|lithium manganese oxide, we propose a new one-step strategy with integrated leaching-sol-gel and subsequent annealing. Through this route, we can successfully prepare LMFP with high phase purity and structurally stable characteristics. The regenerated LMFP exhibits excellent electrochemical performance, delivering an initial discharge capacity of 162 mAh g(-1) at 0.1 C and retaining its capacity without observable degradation after 500 cycles at 1 C. This recycling strategy demonstrates high energy efficiency, economic feasibility, process simplicity, and scalability, highlighting its strong potential for practical application in lithium-ion battery recycling.

With the massive application of lithium-ion batteries in electric vehicles, spent lithium iron phosphate (LFP) batteries have accumulated in recent years, inducing an urgent requirement in recycling technology. Direct repair technology has been considered as a promising approach for recycling spent LFP. However, the traditional solid-phase repair technology is limited by the heterogeneous contact between the lithium source and spent LFP. Herein, polyacrylonitrile (PAN) was selected as the additive to facilitate the intimate contact between the lithium source and spent LFP. PAN displays a strong interaction with defective LFP, leading to the effective contact between spent LFP and the lithium replenishment agent. Moreover, PAN is favorable for the diffusion of lithium ions in the spent LFP lattice during the regeneration process. Therefore, the unevenly distributed FeLi defects in spent LFP are well-repaired. As a result, the regenerated LFP exhibits a high capacity of 155 mA h g-1 at 0.1 C and improved cycling stability with a capacity retention of ∼87% after 400 cycles at 1 C.

In recent years, a large number of spent lithium iron phosphate (LiFePO4, abbreviated as LFP) batteries have been retired. Selective leaching is the most suitable recycling option for spent LFP (S-LFP). However, the current mainstream oxidants and acids are not economical, safe, and green. Herein, we constructed a HNO3-O-2 system to achieve efficient leaching of Li from S-LFP. HNO3 can be recovered by high temperatures after use to achieve the recycling of acid, and O-2 is more economical and safer than mainstream oxidants. In the comfortable oxidizing environment provided by HNO3, O-2 is used to oxidize Fe2+ in S-LFP into Fe3+, and Li+ is extracted from S-LFP into the solution with a leaching rate of almost 100%. The lithium-rich solution is further used to leach the Li from the spent graphite anode, and then the Li in the solution is captured using CO2 to obtain Li2CO3. The iron phosphate (FePO4) slag from Li extraction is regenerated into LFP based on the above obtained Li2CO3 through carbon thermal reduction. The regenerated LFP displays a high discharge capacity of 163.85 mAh g(-1) and a stable cycling performance, which are comparable to those of commercial LFP.

Direct regeneration has been considered as the promising strategy for the recycling of spent LiNixCoyMnzO2 (NCM) cathode materials. The spent NCM suffers from the lithium deficiency in the interior and the phase transition on the surface. The phase transition on the surface suppresses the Li+ diffusion during the direct regeneration process. Surface acid etching is employed to eliminate by-products and degraded phases from spent NCM, aiming to mitigate the Li+ diffusion barrier during regeneration. However, the underlying mechanism of this surface engineering on defect formation and material regeneration remains unclear. Here, we systematically investigated the surface acid etching process and regeneration mechanism of spent NCM. We reveal that controlled surface dissolution of metal ions induces the formation of oxygen vacancies. This enhances Li+ adsorption on the spent NCM surface and facilitates Li+ transport during regeneration process, thus effectively restoring the layered structure and lithium deficiency. Consequently, the regenerated NCM exhibits a discharge capacity of 192.9 mA h g-1 at 0.1 C, surpassing that of the regenerated NCM without etching (188.1 mA h g-1). In addition, the regenerated NCM delivers a high-capacity retention of 92.6% after 100 cycles at 1 C, while that of the regenerated NCM without etching is only 68.8%. This finding provides mechanistic insight into the role of surface oxygen vacancies for promoting NCM regeneration.

Abstract Vanadium oxides are attracted cathodes for aqueous zinc batteries owing to their high capacity. However, the limited cyclability of vanadium‐based oxide cathodes, especially at low current densities, impedes their practical application. Here, it is revealed that proton insertion is responsible for the limited lifetime of vanadium oxides. Proton insertion promotes the dissolution of vanadium oxides, deteriorating electrochemical performance. Propylene carbonate (PC) is introduced into Zn(CF3SO3)2 electrolyte to regulate the coordination environment of water, forming PC‐coordinated Zn2+ solvation structure and [H2O‐CF3SO3−‐PC] complex. The optimized coordination environment of water weakens the adsorption energy between water molecules and vanadium oxides, inhibiting proton insertion. As a result, vanadium‐based oxides cathode without proton insertion can maintain the stability of crystal structure and avoid the dissolution of V. Taking CaV8O20·nH2O as cathode, Zn||CaV8O20·nH2O battery without proton insertion performs enhanced cycling performance. This work not only reveals the negative effect of proton insertion on the lifetime of vanadium‐based oxides cathode but also provides an effective strategy to modulate proton insertion.

As lithium-ion batteries (LIBs) become more widespread, the number of spent LIBs gradually increases. Until now, recycling of spent LIBs has mainly concentrated on high-value cathodes, but the anode graphite has not yet attracted wide attention. In this work, spent graphite from LIBs was oxidized to graphene oxide and then thermally reduced to reduced graphene oxide (RGO), which serves as the cathode of aqueous Zn dual-ion batteries (ZDIBs). The thermal reduction process enables RGO with a large layer spacing and porous structure, which increase the anion insertion sites and transfer kinetics. As a result, the corresponding battery exhibits a high specific capacity of 96.82 mAh g(-1) at 1 A g(-1), superior rate capability, and a high capacity retention rate of 80% after 2000 cycles. Moreover, RGO gradually transforms into a long-range disordered structure during the cycling process, which provides more transport routes and active sites for anion insertion and thus leads to the increase of capacity. This work combines the recycling of spent graphite with aqueous ZDIBs, realizing the high-value use of spent graphite.

With the fast development of lithium-ion batteries, there will be a lot of spent lithium iron phosphate (LFP) batteries in the near future. The loss of lithium in LFP leads to the capacity attenuation, while the lost lithium is mainly trapped in spent graphite anode. Herein, we proposed a closed-loop recycling method for spent LFP batteries, which utilizes the lithium from spent graphite to directly regenerate spent LFP through hydrothermal method. Compared with spent LFP, the repaired LFP displays enhanced electrochemical performance. This strategy tightly integrates the recycling of cathode and anode, which simplifies the recovery process and decreases the recovery cost.

Polyethylene oxide (PEO) is one of the promising substrates for polymer solid electrolyte. However, when coupled with high energy density nickel-rich layered cathode materials, PEO faces the risk of catalytic decomposition by delithium nickel-rich materials. In this work, the in-situ electrochemical passivation strategy is employed to obtain high voltage PEO-based solid-state lithium battery. Trace commercial liquid electrolyte was added on the surface of LiNi0.8Co0.1Mn0.1O2 (NCM811) electrode, and liquid electrolyte is prior to PEO electrolyte to react with the cathode during charge/discharge process, leading to the formation of cathode-electrolyte interface (CEI) layer. The CEI layer avoids the direct contact between PEO and NCM811, thus effectively prevents PEO from being decomposed by NCM811 under high voltage. As a result, the optimized NCM811||PEO||Li battery displays enhanced electrochemical performance, especially cycling performance. This simple but effective strategy not only simplifies the manufacturing process, but also has instructional guidance for high-voltage PEO-based battery.

Fluoride contamination in drinking water is one of the most concerned environmental issues. Herein, a new type of fibrous adsorbent was prepared by polyphenolic chemistry enabled facile synthesis approach that was dependent on the surface modification of chitosan fibers (CF) with plant polyphenols, followed by the chelation with Zr(IV) (CF-Zr). The presence of plant polyphenols allow for a facile and stable anchoring of Zr(IV) onto the CF, which provided sufficient active sites for the adsorption of fluoride at low concentrations. Notably, at low concentration of 2.0 mg/L, the CF-Zr was capable of removing 97.59 % of fluoride, which was considerably higher than commercial activated carbon (3.58 %). The outstanding adsorption performances of CF-Zr to fluoride was attributed to the Zr(IV), which provided high affinity to fluoride by the formation of Zr-oxyfluoride species. The fibrous morphology of the CF-Zr guaranteed a fast adsorption process, with similar to 30 min to reach the adsorption equilibrium. The Langmuir model well fitted the adsorption isotherms, and the corresponding equilibrium adsorption capacity was determined to be 74.52 mg g(-1), close to the experimentally determined maximum adsorption capacity (77.04 mg g(-1)). The fluoride adsorbed onto the CF-Zr was desorbed by NaOH solution, with the desorption percentage of 90.22 %.

Large quantities of spent lithium-ion batteries (LIBs) will inevitably be generated in the near future because of their wide application in many fields. It will cause not only resource waste but also environmental pollution if these spent batteries are not properly handled. Until now, the recycling of spent lithium manganate batteries has centered on high-valuable elements such as lithium; however, manganese element and current collector Al foil have not yet attracted wide attention. In this work, aluminum-doped manganese dioxide was synthesized by overall recycling cathode active materials and current collector Al foil from a spent lithium manganate battery. Employing such aluminum-doped manganese dioxide as the cathode material of aqueous Zn batteries, it displays better electrochemical performance than manganese dioxide prepared by only recycling the cathode active materials. The overall recycling not only simplifies the recycling process but also realizes high-value recycling of spent lithium manganate batteries. We offer new tactics for overall recycling of cathodes from spent LIBs and designing high-performance manganese dioxide cathodes for aqueous Zn batteries.

The utilization of chelation reaction between metals and tannins is a common tanning method in leather chemistry. Herein, a novel combination tanning mechanism inspired environmentally benign catalyst (CMBT-Fe 0 ) was synthesized by immobilizing Fe nanoparticles onto bayberry tannin (BT) grafted chitosan microfibers (CM). The obtained catalyst featured a well-defined microfibrous structure, on which Fe 0 nanoparticles were highly dispersed to exhibit exceptional catalytic activity for the degradation of tetracycline (TC). The catalytic activity of CMBT-Fe 0 was 1.72 times higher than that of the commercial Fe 0 nanoparticles without immobilization, with 95.03% of TC degraded within 90.0 min. The CMBT-Fe 0 catalysts were recycled 6 times, with the removal rate of TC maintained at 82.56%. Furthermore, a possible mechanism responsible for the catalytic removal of TC was provided by analyzing the catalytic degradation products via liquid chromatography-mass spectrometry. Therefore, our investigation successfully developed efficient catalysts to address the concerned environmental issue of antibiotic pollution. Graphical Abstract

Significant concerns have been raised over the removal of antibiotics, such as tetracyclines(TC) in aquatic environments. Herein, we synthesized a new type of heterogeneous catalyst by supporting Fe 0 nanopartciles(FeNPs) onto carbon coated ZIF-8 (C@ZIF-8). The carbon layer formed by glucose was beneficial to maintain the morphology and porous structure of ZIF-8, which can also appropriately improve the hydrophobicity of ZIF-8 for enriching the TC. The as-prepared FeNPs-C@ZIF-8 catalyst featured an extreme large specific surface area(1122.16 m 2 /g), and the supported FeNPs with an average diameter of 6.13 nm exhibited a high dispersity on the supporting matrix of C@ZIF-8. For the removal of tetracycline, the large specific surface area of FeNPs-C@ZIF-8 allowed for an easy access of tetracycline to the FeNPs, while the highly dispersed FeNPs served as actived sites for the efficient degradation of tetracycline. A synergistic effect between adsorption and catalytic degradation of FeNPs(5%, mass fraction)-C@ZIF-8 was proven to be responsible for the high-performance removal of tetracycline with the removal efficiency high up to 93.02% at pH 5, 25 °C. The FeNPs-C@ZIF-8 was capable of recycling after activation with supplementary Fe 0 , which still maintained a high removal efficiency of 75.52% in the 5th cycle within 20 min.

Bimodal mesoporous CeO2-ZrO2-based materials (CZP) are designed and prepared for high specific surface area and thermal stability. CZP is prepared by co-precipitation method and with the help of poly(methyl methacry-late) (PMMA) nanospheres. Its specific surface area reaches 93.8 m2/g higher than 54.8 m2/g of the unimodal mesoporous sample prepared without PMMA nanospheres (CZ). The pores of CZP are in the range of 2-100 nm and concentrate at 4 nm and 14 nm. CZ has narrowly distributed pores ranging from 2 nm to 8 nm. PMMA nanospheres have little effect on the crystal structure of the CeO2-ZrO2-based materials. Compared to CZ, CZP shows higher thermal stability. The specific surface area of CZP is higher than that of CZ at 800 degrees C. At 1000 degrees C, CZP is sintered to sponge-like morphology with pores over 100 nm, while CZ is sintered to dense solid granular morphology. The influence of PMMA nanospheres on oxygen storage capacity (OSC) and redox properties is in line with the changes in specific surface area. In addition, 1000 degrees C aged CZP presents better three-way catalysts (TWC) performance compared to CZ because of the porous sponge-like morphology of CZP.

Herein, a heterogeneous Pd catalyst was prepared by embedding Pd nanoparticles in a highly porous nitrogen-doped mesoporous carbon (NMCs) synthesized by the ZIF-8 template. The as-prepared Pd/NMC catalyst was efficient and recyclable in mild catalytic hydrodechlorination of 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol, showing superior performances to those of the activated carbon-supported Pd commercial catalysts.

Heterogeneous Pd catalysts were developed by immobilizing Pd nanoparticles (Pd NPs) onto plant polyphenol (bayberry tannin, BT) decorated γ-Al 2 O 3 . The abundant hydroxyls of plant polyphenols were capable of stabilizing the Pd NPs. Transmission electron microscopy observation confirmed that the Pd NPs with the diameter of 3.75 ± 0.5 nm were highly dispersed in the catalyst. The as-prepared Al 2 O 3 –BT–Pd catalysts were found to be highly active in mild hydrodechlorination (HDC) of 2,4-dichlorophenols (DCPs) using formic acid as a hydrogen source. The 2,4-DCPs were completely dechlorinated in 4 h at 30°C and under atmospheric pressure. During the catalytic HDC, the stabilizing capability of BT successfully prevented the leakage and aggregation of Pd NPs, thus ensuring a high cycling stability with stable and high catalytic activity. The Al 2 O 3 –BT–Pd catalysts were recycled six times, without obvious loss of activity. In the sixth cycle, the catalytic HDC yield still reached 98.29% under the same reaction conditions, superior to the control catalysts, including γ-Al 2 O 3 supported Pd NPs (Al 2 O 3 –Pd) and powdered activated carbon supported Pd NPs (AC–Pd). Furthermore, the Al 2 O 3 –BT–Pd also showed high activity in the mild catalytic HDC of 2,4,6-trichlorophenols and chlorobenzene derivatives. Our results demonstrated efficient catalysts to address the environmental issue of chlorophenol pollution.

Simultaneous high activity and selectivity are highly desired in heterogeneous catalysis of various important organic intermediate compounds. In the present investigation, we realized ultra-high selective hydrogenation of quinoline to 1,2,3,4-tetrahydroquinoline (py-THQ) under atmospheric conditions by encapsulating 7 +/- 2 nm Pd nanoparticles (PdNPs) inside the 10 +/- 2 nm nanochannels of carbon nanotubes (CNTs). For the prepared Pd@CNTs catalysts, the encapsulated PdNPs was found to selectively absorb the nitrogen heterocyclic ring of quinoline, which led to the increase of average length of C-C bonds in the heterocyclic ring, further resulting in selective activation of the heterocyclic ring and similar to 100% selectivity to py-THQ. The DFT calculations confirmed the selective hydrogenation feature of Pd@CNTs. In contrast, the Pd-CNTs catalyst with PdNPs supported on the outer surface of CNTs is incapable of selectively activate the heterocyclic ring of quinoline, showing poor selectivity and catalytic activity. The Pd@CNTs catalysts also exhibited universal ultra-high selectivity to other quinoline derivatives (7-Methylquinoline, quinaldine and quinoxaline) and oxygen heterocyclic compounds (2,3-benzofuran). Due to the confined effect, the Pd@CNTs catalysts presented superior cycling stability to the Pd-CNTs and activated carbon (AC) impregnated with Pd (Pd-AC) catalysts. The Pd@CNTs catalyst was also found to highly stable in air storage for months, without loss of activity.

Although branched polymers find widespread applications, the rational design and synthesis of branched vinyl polymersviathe conventional radical (co)polymerization of commercially available monomers is still a challenge for researchers in this field.

Aiming at developing highly efficient photocatalysts by broadening the light-harvesting region and suppressing photo-generated electron-hole recombination simultaneously, this work reports rational design and fabrication of donor-acceptor (D-A) conjugated polymer/TiO2 heterojunction catalyst with strong interfacial interactions by a facile in-situ thermal treatment. To expand the light-harvesting window, soluable conjugated copolymers with D-A architecture are prepared by Pd-mediated polycondensation of diketopyrrolopyrrole (DPP) and t-butoxycarbonyl (t-Boc) modified carbazole (Car), and used as visible-light-harvesting antenna to couple with TiO2 nanocrystals. The DPP-Car/TiO2 composites show wide range absorption in 300-1000 nm. To improve the interfacial binding at the interface, a facile in-situ thermal treatment is carried out to cleave the pendant t-Boc groups in carbazole units and liberate the polar amino groups (-NH-) which strongly bind to the surface of TiO2 through dipole-dipole interactions, forming a heterojunction interface. This in-situ thermal treatment changes the surface elemental distribution of TiO2, reinforces the interface bonding at the boundary of conjugated polymers/TiO2 and finally improves the photocatalytic efficiency of DPP-Car/TiO2 under visible-light irradiation. The interface changes are characterized and verified through Fourier-transform infrared spectroscopy (FT-IR), photo images, UV/Vis (solution state and powder diffuse reflection spectroscopy), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fluorescence, scanning electron microscopy(SEM) and transmission electron microscopy (TEM) techniques. This study provides a new strategy to avoid the low solubility of D-A conjugated polymers and construct highly-efficient conjugated polymer/TiO2 heterojunction by enforcing the interface contact and facilitating charge or energy transfer for the applications in photocatalysis. (c) 2017 Elsevier B.V. All rights reserved.

催化氧化苯甲醇是制备苯甲醛的一种简便高效的方法.以天然高分子黑荆树单宁（BWT）为两亲性稳定剂,制备水溶性钯纳米胶体催化剂,用于苯甲醇的氧化反应.采用透射电镜（TEM）、傅里叶变换红外光谱（FT-IR）等表征手段表征所制备催化剂的形貌,探讨制备条件对催化剂形貌的影响.TEM测试表明,单宁的用量对胶体中钯纳米粒子的粒径具有显著的影响,随着BWT用量从2 mg增加到60 mg,Pd粒子的粒径呈现减小趋势.FT-IR测试表明,BWT通过其结构中大量的酚羟基对Pd纳米粒子进行稳定和分散.系统考察单宁用量、反应温度、反应时间等因素对Pd纳米胶体在苯甲醇氧化反应中活性的影响,结果表明:当BWT用量为15 mg时制备的BWT15 mg-Pd胶体催化剂在50℃,空气气氛下8 h催化苯甲醇的转化率高达98.58%; BWT用量对催化剂重复使用性能也有显著的影响,BWT15 mg-Pd可以重复使用5次转化率仍然在90%以上,明显优于BWT5 mg-Pd和BWT60 mg-Pd.

This study focused on the covalent immobilization of TiO2 on the surface of a porous polymer monolith by a two-step method. Firstly, porous polymeric monolith with trimethoxysilane anchor groups was fabricated by w/o emulsion templated copolymerization of vinyl acetate (VAc) and methacryloxypropyl-trimethoxysilane (MPS). Then, anatase TiO2 were covalently immobilized within the voids of poly(VAc-MPS) monolith via an acid-catalyzed co-condensation of the trimethoxysilane group with a TiO2 sol precursor at low temperate. Scanning electron microscopy images demonstrated that both poly(VAc-MPS) and Ti-P(VAc-MPS) possess dense honeycomb-like macroporous structures. The chemical structure analysis by Fourier transform infrared spectroscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy revealed that (i) acid-catalyzed sol-gel method in this case could fully convert the amorphous TiO2 sol to anatase TiO2 even at low temperature (70°); (ii) TiO2 particles were covalently immobilized within the voids of the polymer monolith via Si–O–Ti linkage; (iii) acid-catalyzed hydrolysis of the trimethoxysilane groups and VAc led to significant increase in the hydrophilicity of the obtained hybrid porous monolith, Ti-P(VAc-MPS), with a water contact angle of 19.6°. Exemplified by the photo-degradation of methyl orange (MO) in aqueous solution, Ti-P(VAc-MPs) exhibited good photocatalytic activity and excellent recyclability for water decontamination. The as-prepared Ti-P(VAc-MPS) monolith could be efficiently regenerated for cyclic runs without further energy-consuming separation process such as centrifugation and filtration. The present approach opens a green way for obtaining other porous inorganic-organic photocatalyst for water contaminant removal.