Li-Ga Alloy-Contained Hybrid Solid Electrolyte Interphase Induced by In Situ Polymerization for High-Performance Lithium Metal Batteries.

Construction of quasi-solid-state lithium metal batteries (LMBs) by in situ polymerization is considered a key strategy for the next generation of energy storage systems with high specific energy and safety. Poly(1,3-dioxolane) (PDOL)-based electrolytes have attracted wide attention among researchers, benefiting from the low cost and high ionic conductivity. However, interfacial deterioration and uncontrollable growth of lithium dendrites easily appeared in LMBs due to the high reactivity of lithium metal, resulting in the failure of LMBs. In this work, a strategy is developed of using Ga(OTF)3 as the initiator to obtain a PDOL-based gel electrolyte (GaPD). In addition, a hybrid stable solid electrolyte interphase (SEI) of lithium fluoride/Li2O/Li-Ga alloys is observed on the surface of lithium metal. Combined with density functional theory calculations, the hybrid SEI shows high affinity toward Li+, indicating that a uniform deposition of Li+ could be achieved. Therefore, the Li/GaPD/Li cell operates stably for 1600 h at room temperature. In addition, the LiFePO4/GaPD/Li cell retains a capacity retention rate of 90.2% over 200 cycles at 1 C. This work provides a reference for the practical application of in situ polymerization technology in high-performance and safe LMBs.

Biometabolically Derived Selenium Nanoparticles Armed with Protein Protective Suit toward High-Performance Li-Se Batteries.

Selenium (Se) serves as a burgeoning high-energy-density cathode material in lithium-ion batteries. However, the development of Se cathode is strictly limited by low Se utilization and inferior cycling stability arising from intrinsic volume expansion and notorious shuttle effect. Herein, a microbial metabolism strategy is developed to prepare "functional vesicle-like" Se globules via Bacillus subtilis subsp. from selenite in sewage, in which Se nanoparticles are armed with a natural biological protein membrane with rich nitrogen and phosphorus, achieving the eco-efficient conversion of trash into treasure (selenite, SeO3 2- → Selenium, Se). The appealing-design "functional vesicle-like" Se globules are beneficial to accommodate volume changes of Se in electrochemical reactions, confining polyselenides via chemisorption, and enhancing mechanical strength of electrode by associated bacteria debris, realizing comprehensive utilization of microorganism. By conceptualizing "functional vesicle-like" Se globules, rather than artificial Se-host composites, as cathode for lithium-selenium batteries, it exhibits outstanding cycling stability and improved rate performance. This strategy opens the door to design smart electrode materials with unattainable structure that cannot be achieved by traditional approaches, achieving eco-efficient conversion of pollutants into energy-storage nanomaterials, which will be a promising research field for interdisciplinary of energy, biology, and environment.

In Situ Polymerization Bi-Functional Gel Polymer Electrolyte for High Performance Quasi-Solid-State Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are expected to be the next-generation energy storage system due to the ultrahigh theoretical energy density and low cost. However, the notorious shuttle effect of higher-order polysulfides and the uncontrollable lithium dendrite growth are the two biggest challenges for commercially viable Li-S batteries. Herein, these two main challenges are solved by in situ polymerization of bi-functional gel polymer electrolyte (GPE). The initiator (SiCl4) not only drives the polymerization of 1,3-dioxolane (DOL) but also induces the construction of a hybrid solid electrolyte interphase (SEI) with inorganic-rich compositions on the Li anode. In addition, diatomaceous earth (DE) is added and anchored in the GPE to obtain PDOL-SiCl4-DE electrolyte through in situ polymerization. Combined with density functional theory (DFT) calculations, the hybrid SEI provides abundant adsorption sites for the deposition of Li+, inhibiting the growth of lithium dendrites. Meanwhile, the shuttle effect is greatly alleviated due to the strong adsorption capacity of DE toward lithium polysulfides. Therefore, the Li/Li symmetric cell and Li-S full cell assembled with PDOL-SiCl4-DE exhibit excellent cycling stability. This study offers a valuable reference for the development of high performance and safe Li-S batteries.

A Plastic-Crystal Electrolyte Layer Promotes Interfacial Stability of Ni-Rich Oxide Cathode in Li6PS5Cl-Based All-Solid-State Rechargeable Li Batteries.

Unfavorable parasitic reactions between the Ni-rich layered oxide cathode and the sulfide solid electrolyte have plagued the realization of all-solid-state rechargeable Li batteries. The accumulation of inactive by-products (P2Sx, S, POx n- and SOx n-) at the cathode-sulfide interface impedes fast Li-ion transfer, which accounts for sluggish reaction kinetics and significant loss of cathode capacity. Herein, we proposed an easily scalable approach to stabilize the cathode electrochemistry via coating the cathode particles by a uniform, Li+-conductive plastic-crystal electrolyte nanolayer on their surface. The electrolyte, which simply consists of succinonitrile and Li bis(trifluoromethanesulphonyl)imide, serves as an interfacial buffer to effectively suppress the adverse phase transition in highly delithiated cathode materials, and the loss of lattice oxygen and generation of inactive oxygenated by-products at the cathode-sulfide interface. Consequently, an all-solid-state rechargeable Li battery with the modified cathode delivers high specific capacities of 168 mAh g-1 at 0.1 C and a high capacity retention >80 % after 100 cycles. Our work sheds new light on rational design of electrode-electrolyte interface for the next-generation high-energy batteries.

Li5.5PS4.5Cl1.5-Based All-Solid-State Battery with a Silver Nanoparticle-Modified Graphite Anode for Improved Resistance to Overcharging and Increased Energy Density.

All-solid-state lithium batteries (ASSLBs) are attracting tremendous attention due to their improved safety and higher energy density. However, the use of a metallic lithium anode poses a major challenge due to its low stability and processability. Instead, the graphite anode exhibits high reversibility for the insertion/deinsertion of lithium ions, giving ASSLBs excellent cyclic stability but a lower energy density. To increase the energy density of ASSLBs with the graphite anode, it is necessary to lower the negative/positive (N/P) capacity ratio and to increase the charging voltage. These strategies bring new challenges to lithium metal plating and dendrite growth. Here, a nano-Ag-modified graphite composite electrode (Ag@Gr) is developed to overcome these shortcomings for Li5.5PS4.5Cl1.5-based ASSLBs. The Ag@Gr composite exhibits a strong ability to inhibit lithium metal plating and fast lithium-ion transport kinetics. Ag nanoparticles can accommodate excess Li, and the as-obtained Li-Ag alloy enhances the kinetics of the composite electrode. The ASSLB with the Li(Ni0.8Co0.1Mn0.1)O2 cathode and Ag@Gr anode achieves an energy density of 349 W h kg-1. The full cell using Ag@Gr with an N/P ratio of 0.6 also highlights the rate performance. This work provides a simple and effective method to regulate the charge transport kinetics of graphite anodes and improve the cyclic performance and energy density of ASSLBs.

A Stable Lithium Metal Anode Enabled by the Site-Directed Lithium Deposition of ZnO-Nanosheet-Modified Carbon Cloth.

Uneven lithium (Li) metal deposition typically results in uncontrollable dendrite growth, which renders an unsatisfactory cycling stability and coulombic efficiency (CE) of Li metal batteries (LMBs), preventing their practical application. Herein, a novel carbon cloth with the modification of ZnO nanosheets (ZnO@CC) is fabricated for LMBs. The as-prepared ZnO@CC with a cross-linked network significantly reduces the local current density, and the design of ZnO nanosheets can promote the uniform deposition of Li metal as lithiophilic sites. As a result, the Li metal anodes (LMAs) based on ZnO@CC (ZnO@CC@Li) enables a long cycle life over 640 hours with a low overpotential of 65 mV at a current density of 4 mA cm-2 with a capacity of 1 mAh cm-2 in the symmetric cell. Moreover, when coupling the ZnO@CC@Li with a LiFePO4 cathode, the assembled full cell exhibits excellent long cycle and rate performance, highlighting its promising practical application prospect.

In Situ Construction of LiF-Li3N-Rich Interface Contributed to Fast Ion Diffusion in All-Solid-State Lithium-Sulfur Batteries.

All-solid-state lithium-sulfur batteries (ASSLSBs) have attracted wide attention due to their ultrahigh theoretical energy density and the ability of completely avoiding the shuttle effect. However, the further development of ASSLSBs is limited by the poor kinetic properties of the solid electrode interface. It remains a great challenge to achieve good kinetic properties, by common strategies to substitute sulfur-transition metal and organosulfur composites for sulfur without reducing the specific capacity of ASSLSBs. In this study, a sulfur-(Ketjen Black)-(bistrifluoromethanesulfonimide lithium salt) (S-KB-LiTFSI) composite is constructed by introducing LiTFSI into the S-KB composite. The initial discharge capacity reaches up to 1483 mA h g-1, benefited from the improved ionic conductivity and diffusion kinetics of the S-KB-LiTFSI composite, where numerous LiF interphases with a Li3N component are in situ formed during cycling. Combined with DFT calculations, it is found that the migration barriers of LiF and Li3N are much smaller than that of the Li6PS5Cl solid electrolyte. The fast ionic conductors of LiF and Li3N not only enhance the Li+ transfer efficiency but also improve the interfacial stability. Therefore, the assembled ASSLSBs operate stably for 600 cycles at 200 mA g-1, and this study provides an effective strategy for the further development of ASSLSBs.

Plasma Technology for Advanced Electrochemical Energy Storage.

"Carbon Peak and Carbon Neutrality" is an important strategic goal for the sustainable development of human society. Typically, a key means to achieve these goals is through electrochemical energy storage technologies and materials. In this context, the rational synthesis and modification of battery materials through new technologies play critical roles. Plasma technology, based on the principles of free radical chemistry, is considered a promising alternative for the construction of advanced battery materials due to its inherent advantages such as superior versatility, high reactivity, excellent conformal properties, low consumption and environmental friendliness. In this perspective paper, we discuss the working principle of plasma and its applied research on battery materials based on plasma conversion, deposition, etching, doping, etc. Furthermore, the new application directions of multiphase plasma associated with solid, liquid and gas sources are proposed and their application examples for batteries (e. g. lithium-ion batteries, lithium-sulfur batteries, zinc-air batteries) are given. Finally, the current challenges and future development trends of plasma technology are briefly summarized to provide guidance for the next generation of energy technologies.

Facile Synthesis of Pre-Lithiated LiTiO2 Nanoparticles for Quick Charge and Long Lifespan Anode in Lithium-Ion Batteries.

Titanium dioxide (TiO2) has been widely used as an alternative anodic material for lithium-ion batteries (LIBs) due to its ultrahigh capacity retention and long cycle lifespan. However, the restriction of lithium insertion, intrinsically poor electronic conductivity, and sluggish lithium ionic kinetics of bulk TiO2 hinder their specific capacity and rate performance. Herein, LiTiO2 nanoparticles (NPs) are synthesized via a facile ball milling method by the reaction of anatase TiO2 with LiH. The as-prepared LiTiO2 NPs have strong structural stability and a "zero strain" effect during the repeated intercalation/deintercalation, even at low potential. As anodic materials for LIBs, LiTiO2 NPs exhibit a superior rate performance of ∼100 mA h g-1 at 10C (3350 mA g-1) with a capacity retention of 100% after 1000 cycles, which is 5 times higher than that of the original commercial anatase TiO2 powder. The higher specific capacity of LiTiO2 NPs is attributed to the increased conversion of Ti3+ to Ti2+ on the porous surface of LiTiO2 NPs, which provides a more capacitive contribution. This study not only provides a new fabrication approach toward Ti-based anodes for ultrafast LIBs but also underscores the potential importance of embedding lithium into transition metal oxides as a strategy for boosting their electrochemical performance.

An approach to enhance carbon/polymer interface compatibility for lithium-ion supercapacitors.

Developing high-efficiency and easy machining components, as well as high-performance energy storage components, is a pressing issue on the road to economic and social progress. Optimizing the interface compatibility between composites and promoting the efficient utilization of the electrochemical active sites are crucial factors in improving the electrochemical performance of composite electrode materials. To address this challenge, a carbon-based flexible lithium-ion supercapacitor positive material (Polyaniline @ Carbon Foam-Supercritical carbon dioxide (P@C-SC)) is synthesized using commercial melamine foam and aniline monomer. The synthesis process utilizes supercritical fluid technology, effectively solving the interface compatibility problem between the composite materials. Consequently, the electrochemical performance of the composite electrode materials is significantly improved. The supercapacitive properties of this material are investigated in 1 mol/L sulfuric acid (H2SO4) and lithium sulfate (Li2SO4) electrolytes using a three-electrode system. In H2SO4 electrolyte, the material exhibits a working voltage of up to 2.2 V and a specific capacitance of 898F/g (at 1 A/g), resulting in a maximum energy density of 50.8 Wh kg-1. Furthermore, this electrode demonstrates superior lithium storage performance, with a specific capacity of approximately 900 mAh/g (at 1 A/g) and a retention of about 400 mAh/g after 200 cycles, along with a coulomb efficiency of 100%. This work offers insights into the integrated design of composite materials with improved electrochemical properties and interface compatibility, thus providing potential applicability of supercritical fluids in the field of lithium-ion supercapacitors.

LiF-Rich Interfacial Protective Layer Enables Air-Stable Lithium Metal Anodes for Dendrite-Free Lithium Metal Batteries.

Lithium (Li) metal is considered as a promising anode candidate for high-energy-density batteries. However, the high reactivity of Li metal leads to poor air stability, limiting its practical application. Additionally, the interfacial instability, such as dendrite growth and an unstable solid electrolyte interphase layer, further complicates its utilization. Herein, a dense lithium fluoride (LiF)-rich interfacial protective layer is constructed on the Li surface through a simple reaction between Li and fluoroethylene carbonate (denoted as LiF@Li). The LiF-rich interfacial protective layer consists of both organic (ROCO2Li and C-F-containing species, which only exist on the outer layer) and inorganic (LiF and Li2CO3, distribute throughout the layer) components with a thickness of ∼120 nm. Specifically, chemically stable LiF and Li2CO3 play an important role in blocking air and hence improve the air durability of LiF@Li anodes. Notably, LiF with high Li+ diffusivity facilitates uniform Li+ deposition, while organic components with high flexibility relieve volume change upon cycling, thereby enhancing the dendrite inhibition capacity of LiF@Li. Consequently, LiF@Li exhibits remarkable stability and excellent electrochemical performance in both symmetric cells and LiFePO4 full cells. Moreover, LiF@Li maintains its initial color and morphology even after air exposure for 30 min, and the air-exposed LiF@Li anode still retains its superior electrochemical performance, further establishing its outstanding air-defendable capability. This work proposes a facile approach in constructing air-stable and dendrite-free Li metal anodes toward reliable Li metal batteries.

High-Performance Solid Lithium Metal Batteries Enabled by LiF/LiCl/LiIn Hybrid SEI via InCl3 -Driven In Situ Polymerization of 1,3-Dioxolane.

The use of poly(1,3-dioxolane) (PDOL) electrolyte for lithium batteries has gained attention due to its high ionic conductivity, low cost, and potential for large-scale applications. However, its compatibility with Li metal needs improvement to build a stable solid electrolyte interface (SEI) toward metallic Li anode for practical lithium batteries. To address this concern, this study utilized a simple InCl3 -driven strategy for polymerizing DOL and building a stable LiF/LiCl/LiIn hybrid SEI, confirmed through X-ray photoelectron spectroscopy (XPS) and cryogenic-transmission electron microscopy (Cryo-TEM). Furthermore, density functional theory (DFT) calculations and finite element simulation (FES) verify that the hybrid SEI exhibits not only excellent electron insulating properties but also fast transport properties of Li+ . Moreover, the interfacial electric field shows an even potential distribution and larger Li+ flux, resulting in uniform dendrite-free Li deposition. The use of the LiF/LiCl/LiIn hybrid SEI in Li/Li symmetric batteries shows steady cycling for 2000 h, without experiencing a short circuit. The hybrid SEI also provided excellent rate performance and outstanding cycling stability in LiFePO4 /Li batteries, with a high specific capacity of 123.5 mAh g-1 at 10 C rate. This study contributes to the design of high-performance solid lithium metal batteries utilizing PDOL electrolytes.

Slurry-Coated LiNi0.8Co0.1Mn0.1O2-Li3InCl6 Composite Cathode with Enhanced Interfacial Stability for Sulfide-Based All-Solid-State Batteries.

The implementation of all-solid-state lithium batteries (ASSLBs) is regarded as an important step toward the next-generation energy storage systems. The sulfide solid-state electrolyte (SSE) is a promising candidate for ASSLBs due to its high ionic conductivity and easy processability. However, the interface stability of sulfide SSEs toward high-capacity cathodes like nickel-rich layered cathodes is limited by the interfacial side reaction and narrow electrochemical window of the electrolyte. Herein, we propose introducing the halide SSE Li3InCl6 (LIC) with high (electro)chemical stability and superior Li+ conductivity to act as an ionic conductive additive in the Ni-rich LiNi0.8Co0.1Mn0.1O2 (NCM) cathode mixture through a slurry coating, aiming to build a stable cathode-electrolyte interface. This work demonstrates that the sulfide SSE Li5.5PS4.5Cl1.5 (LPSCl) is chemically incompatible with the NCM cathode, and the indispensable role of the substitution of LPSCl with LIC in enhancing the interfacial compatibility and oxidation stability of the electrolyte is highlighted. Accordingly, this new configuration shows superior electrochemical performance at room temperature. It shows a high initial discharge capacity (136.3 mA h g-1 at 0.1C), cycling performance (77.4% capacity retention at the 100th cycle), and rate capability (79.3 mA h g-1 at 0.5C). This work paves the way for investigating interfacial challenges regarding high-voltage cathodes and provides new insights into possible interface engineering strategies.

New Chemical Synthesis Strategy To Construct a Silicon/Carbon Nanotubes/Carbon-Integrated Composite with Outstanding Lithium Storage Capability.

The Si/C anode is one of the most promising candidate materials for the next-generation lithium-ion batteries (LIBs). Herein, a silicon/carbon nanotubes/carbon (Si/CNTs/C) composite is in situ synthesized by a one-step reaction of magnesium silicide, calcium carbonate, and ferrocene. Transmission electron microscopy reveals that the growth of CNTs is attributed to the catalysis of iron atoms derived from the decomposition of ferrocene. In comparison to a Si/C composite, the cycle stability of the Si/CNTs/C composite can obviously be improved as an anode for LIBs. The enhanced performance is mainly attributed to the following factors: (i) the perfect combination of Si nanoparticles and in situ grown CNTs achieves high mechanical integrity and good electrical contact; (ii) Si nanoparticles are entangled in the CNT cage, effectively reducing the volume expansion upon cycling; and (iii) in situ grown CNTs can improve the conductivity of composites and provide lithium ion transport channels. Moreover, the full cell constructed by a LiFePO4 cathode and Si/CNTs/C anode exhibits excellent cycling stability (137 mAh g-1 after 300 cycles at 0.5 C with a capacity retention rate of 91.2%). This work provides a new way for the synthesis of a Si/C anode for high-performance LIBs.

Stable LiF-Rich Electrode-Electrolyte Interface toward High-Voltage and High-Energy-Density Lithium Metal Solid Batteries.

Lithium-rich layered oxide (LRLO) materials have attracted significant attention due to their high specific capacity, low cost, and environmental friendliness. However, owing to its unique capacity activation mechanism, the release of lattice oxygen during the first charge process leads to a series of problems, such as severe voltage decay, poor cycle stability, and poor rate performance. Herein, a fluorinated quasi-solid-state electrolyte (QSSE) via a simple thermal polymerization method toward lithium metal batteries with LRLO materials is reported. The well-designed QSSE exhibits an ionic conductivity of 6.4 × 10-4 S cm-1 at 30 °C and a wide electrochemical stable window up to 5.6 V. Most importantly, XPS spectra demonstrate the generation of a LiF-rich electrode-electrolyte interface (EEI), where the in situ generated LiF provides strong protection against the structural degradation of LRLO materials and directs the uniform plating/stripping behaviors of lithium-ions to inhibit the formation of lithium dendrites. As a result, LRLO/QSSE/Li batteries exhibit excellent rate performance and demonstrate a large initial capacity for 209.7 mA h g-1 with a capacity retention of 80.8% after 200 cycles at 0.5C. This work provides a new insight for the LiF-rich EEI design of safe, high-performance quasi-solid-state lithium metal batteries.

Effective SrWO4 /TiO2 Heterojunction with Enhanced Carriers Separation and Transfer for Photocatalytic Methane Oxidation.

Photocatalytic methane oxidation to oxygenates with promising performance remains as a grand challenge due to the low productivity and severe overoxidation. Herein, SrWO4 /TiO2 heterojunction was developed for photocatalytic methane oxidation with O2 to liquid oxygenates ( Please replace "oxygenates" with "oxygenated")products under mild reaction conditions. The optimized SrWO4 /TiO2 catalyst exhibited high productivity of 13365 µmol/g with high selectivity of 98.7 % for oxygenates. Benefited from the intimate heterojunction interface of SrWO4 /TiO2 , the constructed I-type heterostructure improved the separation and transfer of photogenerated carriers, and a high-speed transfer channel for photogenerated carriers was fabricated. Simultaneously, the special band structure can increase the amount of photogenerated electrons and holes on the TiO2 surface, which promoted the formation of reactive oxygen species to enhance liquid oxygenates productivity.

Three-dimensional polyimide nanofiber framework reinforced polymer electrolyte for all-solid-state lithium metal battery.

The replacement of traditional liquid electrolytes with polyethylene oxide (PEO) based composite polymer electrolytes (CPEs) is an important strategy to address the current flammability and explosiveness of lithium batteries since PEO CPEs have high flexibility, excellent processability and moderate cost. However, the insufficient ionic conductivity and inferior mechanical strength of PEO CPEs do not suit the operating requirements of all-solid-state lithium metal batteries at room temperature. Herein, three-dimensional (3D) framework composed of interweaved high-modulus polyimide (PI) nanofibers along with functional succinonitrile (SN) plasticizers are employed to synergistically reinforce the ionic conductivity and mechanical strength of PEO CPEs. Impressively, benefitting from the synergistic effects of 3D PI framework and SN plasticizer, PI-PEO-SN CPEs exhibits high ionic conductivity of 1.03 × 10-4 S cm-1 at 30 °C, remarkable tensile strength of 4.52 MPa, and superior Li dendrites blocking ability (>400 h at 0.1 mA cm-2). Such favorable features of PI-PEO-SN CPEs endow LiFePO4/PI-PEO-SN/Li solid-state prototype cells with high specific capacity (151.2 mA h g-1 at 0.2 C), long cycling lifespan (>150 cycles with 91.7 % capacity retention), and superior operating safety even under bending, folding and cutting harsh conditions. This work will pave the avenues to design and fabricate new high-performance PEO CPEs for the high energy density and safety all-solid-state batteries.

Argyrodite Solid Electrolyte-Integrated Ni-Rich Oxide Cathode with Enhanced Interfacial Compatibility for All-Solid-State Lithium Batteries.

All-solid-state lithium batteries (ASSLBs) paired with an argyrodite sulfide solid electrolyte have become a candidate to take the world by storm for achieving high energy and safety. However, the undesirable interface design between a sulfide solid electrolyte and cathode is difficult to address its scalability production challenge. Particularly, the inferior interfacial contact between a sulfide solid electrolyte and cathode is an intractable obstacle for the large-scale commercial application of ASSLBs. Herein, an elaborately designed conformally in situ integration of a sulfide solid electrolyte onto a Ni-rich oxide cathode is proposed to overcome this issue through a facile tape casting method. In this unique integrated electrode structure, the sulfide solid electrolyte intimately makes contact with the Ni-rich oxide cathode, which significantly strengthens the solid-solid interfacial compatibility, as well as decreases the interfacial reaction resistances, thereby enabling rapid Li+ transportation and a stable interfacial structure. As a result, ASSLBs consisting of a sulfide solid electrolyte-integrated Ni-rich oxide cathode and Li anode exhibit high discharge capacity, excellent cyclic stability, and remarkable rate performance, which are superior to the cells with segregated structures composed of a Ni-rich oxide cathode, sulfide solid electrolyte, and Li anode. The features clearly indicate that the advanced interfacial contact between the cathode and solid electrolyte is responsible for ASSLBs with low polarization and fast reaction kinetics. Therefore, this work provides a rational proof-of-concept fabrication protocol for the reliable interfacial structure design of high-performance ASSLBs.

Highly Selective Photocatalytic Aerobic Oxidation of Methane to Oxygenates with Water over W-doped TiO2.

Highly selective conversion of methane to oxygenates with O2 as a green oxidant remains a great challenge. It is still difficult to suppress the generation of COx (x=1, 2) as undesired by-products due to unavoidable overoxidation reaction. Hence, tungsten-doped (W-doped) TiO2 photocatalysts were designed with a tunable band structure for photocatalytic oxidation of methane to C1 oxygenates using O2 at low temperature (30 °C). The W-doping effectively modified the electronic and band structure of pristine TiO2 to enhance photocatalytic performance. Liquid oxygenates productivity could reach as high as 12.2 mmol g-1 with high selectivity of 99.4 %. Moreover, COx selectivity was effectively decreased from 21.2 % over TiO2 to 0.6 % for W-doped catalyst. Detailed characterizations further disclosed that W-doping not only enhanced light absorption, but also promoted the separation of photo-generated carriers to improve methane conversion. This work provides new insights into the design of highly efficient photocatalysts for methane oxidation.

A Facile Pre-Lithiated Strategy towards High-Performance Li2Se-LiTiO2 Composite Cathode for Li-Se Batteries.

Conventional lithium-ion batteries with a limited energy density are unable to assume the responsibility of energy-structure innovation. Lithium-selenium (Li-Se) batteries are considered to be the next generation energy storage devices since Se cathodes have high volumetric energy density. However, the shuttle effect and volume expansion of Se cathodes severely restrict the commercialization of Li-Se batteries. Herein, a facile solid-phase synthesis method is successfully developed to fabricate novel pre-lithiated Li2Se-LiTiO2 composite cathode materials. Impressively, the rationally designed Li2Se-LiTiO2 composites demonstrate significantly enhanced electrochemical performance. On the one hand, the overpotential of Li2Se-LiTiO2 cathode extremely decreases from 2.93 V to 2.15 V. On the other hand, the specific discharge capacity of Li2Se-LiTiO2 cathode is two times higher than that of Li2Se. Such enhancement is mainly accounted to the emergence of oxygen vacancies during the conversion of Ti4+ into Ti3+, as well as the strong chemisorption of LiTiO2 particles for polyselenides. This facile pre-lithiated strategy underscores the potential importance of embedding Li into Se for boosting electrochemical performance of Se cathode, which is highly expected for high-performance Li-Se batteries to cover a wide range of practical applications.