Realizing an energy‐dense, highly rechargeable nonaqueous lithium–oxygen battery in ambient air remains a big challenge because the active materials of the typical high‐capacity cathode (Li2O2) and ...anode (Li metal) are unstable in air. Herein, a novel lithium–oxygen full cell coupling a lithium anode protected by a composite layer of polyethylene oxide (PEO)/lithium aluminum titanium phosphate (LATP)/wax to a LiOH‐based cathode is constructed. The protected lithium is stable in air and water, and permits reversible, dendrite‐free lithium stripping/plating in a wet nonaqueous electrolyte under ambient air. The LiOH‐based full cell reaction is immune to moisture (up to 99% humidity) in air and exhibits a much better resistance to CO2 contamination than Li2O2, resulting in a more consistent electrochemistry in the long term. The current approach of coupling a protected lithium anode with a LiOH‐based cathode holds promise for developing a long‐life, high‐energy lithium–air battery capable of operating in the ambient atmosphere.
A highly rechargeable lithium‐air battery operating directly in ambient environment is successfully demonstrated by coupling a LiOH‐based cathode and an air‐stable lithium anode with a composite protective layer. Key advantages of the system include: 1) outstanding electrochemical stability; 2) Li dendrite‐free; 3) superior resistance to humidity (99%) and CO2; 4) being applicable to highly wet electrolytes (up to 50vol%).
Lithium‐sulfur batteries (LSB) are one of the potential candidates for the next generation of electrochemical energy storage technology, due to their advantages of high theoretical capacity and high ...energy density. However, sluggish redox kinetics and the shuttle effect of polysulfides in the cyclic process lead to low sulfur utilization, severe polarization and poor cyclic stability. Herein, an SnS modified porous carbon nanosheet (SnS/PCNS) hybrid material is synthesized by a simple hydrothermal method and used to modify the separator of the LSB for the first time. Specifically, SnS/PCNS can not only adsorb polysulfides, but also enhance the redox reaction of polysulfides. In addition, SnS/PCNS are shown to promote rapid nucleation and uniform deposition of Li2S, and to improve the discharge capacity and heighten cyclic stability. The initial capacity is 1270 mAh g−1 at 0.5 C, the slow decay rate of each cycle is 0.039% at 1 C. When the sulfur loading is improved to 6 mg cm−2, the high reversible capacity is 955.3 mAh g−1 at 0.5 C. As a new polysulfides adsorbent, SnS provides a potential route for the commercialization of LSBs.
A highly stable and long‐cycle life lithium‐sulfur battery is successfully achieved via a SnS and porous carbon nanosheet (PCNS) modified separator, in which the SnS/PCNS has a strong adsorption effect on polysulfide, together with good catalytic activity and high conductivity.
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•Zinc sulfide can catalyze the transformation of polysulfide.•The anion vacancy produced by the phase transition of zinc sulfide is helpful to capture polysulfide.•Carbon nanosheet ...skeleton is beneficial to the reuse of active substances.•ZnS/NCNS can accommodate a cathode with high areal loading.
Stabilizing the lithium anode while inhibiting the shuttle effect to achieve stable circulation under high sulfur loading is an inevitable problem for the commercialization of lithium-sulfur batteries. A low cost of raw materials and a simple synthesis are also important prerequisites for product commercialization. In this paper, zinc sulfide (ZnS) nanoparticles embedded in nitrogen-doped 3D-carbon nanosheets (NCNS) are proposed as modified separator materials. During high-temperature carbonization of the carbon materials, a zinc sulphide phase transition occurs, resulting in an anion vacancy (S2-) and an unsaturated Zn centre. While maintaining catalytic activity, the unsaturated Zn centre in ZnS acts as a Lewis acid to form a coordinate bond with the polysulfide. Furthermore, a uniform distribution of N heteroatoms can effectively regulate Li+ flux through the separator, thereby achieving a stable cycle for the lithium anode. A cell with the ZnS/NCNS-modified separator can achieve a stable cycle at 0.5 C and superior electrochemical performance even with an areal sulfur loading of 6 mg cm−2. An excellent reduction in self-discharge was also confirmed by a 4% capacity attenuation after resting for 4 days. This work provides new insight on the design and preparation of novel separators for highly stable Li–S batteries via a “green” and cost-effective approach.
Lithium-sulfur (Li-S) batteries are extremely attractive because of their high theoretical capacities, energy densities, and cost-effectiveness, as well as the environmental friendliness of elemental ...sulfur. However, the commercialization of Li-S batteries is impeded by fast capacity fading and harsh self-discharge. To overcome these issues, effort has been dedicated to improving performance by designing the electrode structure and composition, which is often expensive and complex. In this study, modification of the separator by a combination of commercial titanium monoxide and multiwall carbon nanotubes (TiO/MWCNTs) was first designed, which is a low-cost and simple preparation process. The cooperative effect of TiO and MWCNTs capacitates the feedback of the Li-S cell with a relatively high premier discharge capacity of 1527.2 mAh g−1, and excellent cycling stability is obtained up to 1000 cycles at 0.5 C with a negligible fading rate of 0.057% per cycle. And the self-discharge behavior was improved obviously. When the time of rest was extended to 96 h, the capacity attenuation of the cell with the TiO/MWCNT coating was only 12.4%. The use of a TiO/MWCNT-coated separator is a feasible method for the commercial success of high-performance Li-S batteries.
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•TiO/MWCNT composite is firstly used to modify the separator of Li-S battery.•High density of oxygen and titanium vacancies of TiO is benefit for adsorbing LiPSs.•MWCNT network as a physical barrier improves the conductivity of the separator.•The strong adsorption of TiO/MWCNT suppress the shuttle effect of Li-S battery.
Bisphenol A (BPA), a synthetic organic chemical, is creating a new category of ecological and human health challenges due to unintended leakage. Effectively managing the use and leakage of BPA can ...benefit from an understanding of the anthropogenic BPA cycles (i.e., the size of BPA flows and stocks). In this work, we provide a dynamic analysis of the anthropogenic BPA cycles in China for 2000–2014. We find that China’s BPA consumption has increased 10-fold since 2000, to ∼3 million tonnes/year. With the increasing consumption, China’s in-use BPA stock has increased 500-fold to 14.0 million tonnes (i.e., 10.2 kg BPA/capita). It is unclear whether a saturation point has been reached, but in 2004–2014, China’s in-use BPA stock has been increasing by 0.8 kg BPA/capita annually. Electronic products are the biggest contributor, responsible for roughly one-third of China’s in-use BPA stock. Optical media (DVD/VCD/CDs) is the largest contributor to China’s current End-of-Life (EoL) BPA flow, totaling 0.9 million tonnes/year. However, the EoL BPA flow due to e-waste will increase quickly, and will soon become the largest EoL BPA flow. The changing quantities and sources of EoL BPA flows may require a shift in the macroscopic BPA management strategies.
Rechargeable aqueous zinc-ion batteries (ZIBs) are possible future replacements for large-scale energy storage devices because of their safety, low cost, and abundance of materials. Finding a ...competitive cathode material suitable for zinc-ion insertion/de-insertion, needed to achieve high reversible capacity and long cycle stability, is one of the most important and arduous challenges. For the first time, nickel and cobalt co-substituted spinel ZnMn2O4 nanoparticles, homogeneously loaded onto N-doped reduced graphene oxide (ZnNixCoyMn2-x-yO4@N-rGO), were synthesised through a one-step hydrothermal method and applied as a cathode material to accommodate the intercalation of zinc ions. The as-prepared ZnNixCoyMn2-x-yO4@N-rGO displayed excellent electrochemical performance, with a reversible capacity of 95.4 mA h g−1, achieved at 1000 mA g−1 after 900 cycles, and a capacity retention ratio of 79%. When the current density increased from 10 mA g−1 to 1500 mA g−1, high capacity (200.5 mA h g−1 to 93.5 mA h g−1) was achieved, which was much higher than that of ZMO@N-rGO without nickel and cobalt co-substituting (184 mA h g−1 to 59.2 mA h g−1), demonstrating excellent rate performance. These excellent electrochemical properties are attributed to the co-substituting of nickel and cobalt elements, which is an effective approach to promote Zn2+ de-intercalation and to stabilize the spinel structure in order to suppress the Jahn-Teller distortion of Mn3+. Therefore, nickel and cobalt co-substituting of spinel ZnMn2O4@N-rGO with a stable structure opens up new possibilities for large-scale application of rechargeable, aqueous ZIBs.
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•Nickel and cobalt co-substituted spinel ZnMn2O4 nanoparticles were synthesised•The ultrafine ZnNi0.39Co0.59Mn0.98O4 loaded onto N-doped reduced graphene oxide.•The ZnNi0.39Co0.59Mn0.98O4@N-rGO exhibited excellent performance as a cathode for SIBs.•Nickel and cobalt co-substituting stabilized the spinel structure.•The N-doped graphene network ensured highly electronic conductivity.
VS2, as a typical transition-metal diahalcogenide with hexagonal structure, has attracted considerable attention as an electrode material for aqueous zinc-ion batteries (ZIBs) owing to its large ...layer spacing, which is beneficial for Zn2+ intercalation/deintercalation. However, due to the solubility of the vanadium element, the stability of VS2 is poor in aqueous electrolytes, which results in severe capacity degradation and limits its practical applications. In this work, a hydrophilic VOOH coating on rose-like VS2 composed of nanosheets (VS2@VOOH) is synthesized by a simple one-pot hydrothermal method. The O–H in VOOH do not only improve the infiltration of the electrode and the electrolyte, but also reduce the dissolution of vanadium and increased electrochemical performance, especially in terms of rate capability and long cycle life. For instance, this composite material, as an aqueous ZIB cathode, delivers a superior capacity of 107.5 mA h g−1 after 350 cycles at 1.5 A g−1. In particularly, it can maintain a reversible capacity of 91.4 mA h g−1 even after 400 cycles at a high current density of 2.5 A g−1. Therefore, we believe that VS2@VOOH may be regarded as a very promising cathode material for ZIBs.
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•VS2@VOOH is synthesized by a simple one-pot hydrothermal method.•The robust rose-like structure improves cycle stability of VS2@VOOH.•The surface VOOH protects the VS2 from dissolution.•The surface VOOH enhances the infiltration of the electrode and the electrolyte.•VS2@VOOH exhibits competitive electrochemical performance for zinc ion storage.
The realization of practical nonaqueous lithium–air batteries (LABs) calls for novel strategies to address their numerous theoretical and technical challenges. LiOH formation/decomposition has ...recently been proposed as a promising alternative route to cycling LABs via Li2O2. Herein, the progress in developing LiOH‐based nonaqueous LABs is reviewed. Various catalytic systems, either soluble or solid‐state, that can activate a LiOH‐based electrochemistry are compared in detail, with emphasis in providing an updated understanding of the oxygen reduction and evolution reactions in nonaqueous media. We identify the key factors that can switch the cell chemistry between Li2O2 and LiOH and highlight the debate around these routes, as well as rationalize potential causes for these opposing opinions. The identities of the reaction intermediates, activity of redox mediators and additives, location of reaction interfaces, causes of parasitic reactions, as well as the effect of CO2 on the LiOH electrochemistry, all play a critical role in altering the relative rates of a series of interconnected reactions and all warrant further investigation.
The progress in developing LiOH‐based nonaqueous lithium–air batteries is reviewed, with emphasis in providing an updated understanding of the oxygen reduction/evolution reactions during cell operation. Many fundamental questions remain unanswered on the identities of the reaction intermediates, locations of reaction interfaces, causes of parasitic reactions, and the effect of CO2 on the LiOH electrochemistry, which all warrant further investigation.
MoS2 has attracted remarkable attention, attributed to its high specific capacity and graphite-like structure. However, the low rate capability and poor cycle stability are two major obstacles that ...hinder the practical application of MoS2 in sodium-ion batteries (SIBs). Herein, MoS2 grows vertically on the surface of reduced graphene oxide (rGO) and forms a nanowall structure by electrostatic attraction, whose growth has been induced by cetyltrimethyl ammonium bromide (CTAB). This unique nanowall has a large specific surface area, which not only exposes plenty of active sites and shortens the diffusion distance of Na+, but also improves the electronic conductivity and structural stability. Meanwhile, detailed kinetic analysis is also employed to explain the Na+ storage behavior. The pseudo capacitance-dominated contribution ensures a more stable and much faster Na+ storage. Therefore, the MoS2@rGO composite displays excellent electrochemical performance. For example, the capacity of the MoS2@rGO composite can still be maintained at 571.5 mA h g−1 with 94.1% retention, after 100 cycles at 0.1 A g−1. Impressively, MoS2@rGO still exhibits a considerable capacity of 124 mA h g−1 at an ultra-high current density of 40 A g−1. The excellent performance makes the MoS2@rGO material a prospective electrode for use in large-scale SIBs.
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•The MoS2 nanowalls grow vertically on the rGO surface by electrostatic attraction.•The combination of MoS2 nanowalls and rGO is strengthened by forming a C–S bond.•The composite with MoS2 nanowalls structure has a large specific surface area.•The MoS2 nanowalls allows Na+ to deintercalate rapidly along the horizontal direction.•The MoS2@rGO composite shows superior cycle and rate performance in SIBs.
•The tungsten cycle in China from 1949 –2017 has been quantified for the first time.•China's tungsten dominance only exists in low value-added products which face over-capacity issues.•China's future ...tungsten supply will be constrained by the declining tungsten ore quality.•China is a net-exporter of tungsten products, but has high dependence on tech-intensive tungsten products from other nations.
Tungsten is deemed a critical raw material by many nations, given its irreplaceable use in industrial and military applications. In particular, much concern has been drawn to China's high share in global tungsten supply. While various studies have focused on the criticality of tungsten, few have specifically explored how tungsten is produced, consumed, and traded. In this paper, the dynamic material flow analysis is applied to quantify China's annual tungsten cycle from 1949 – 2017. It is estimated that total tungsten mined from ores in China over the past 68-year period is ~2500 kilo-tons (kt). Among those, ~750 kt of tungsten has been exported to other countries, and around 970 kt tungsten is domestically consumed. It is noted ≈1720 kt has been lost from mining, production, and end-of-life stage, and merely ~130 kt has been recycled as end-of-life scrap. Our material flow analysis further refined China's tungsten dominance. Although China currently dominates the global production of tungsten, this dominance will not extend too far into the future given China's limited share of world tungsten reserves and its declining ore quality. Our trade flow analysis reveals that China imported ~35 kt of high value-added downstream tungsten products from outside manufacturers, whose mineral resource was originally imported from China. At present, China by itself is experiencing overcapacity issues in the primary production, which discourages the recycling of at end-of-life (EoL) stage and makes the EoL recycling rate only 10%. It is noted that the percentage of Chinese tungsten for domestic consumption has been increasing in the past few years. This highlights the need for systematic measures from stakeholders along the tungsten cycle to promote sustainable practices for efficient tungsten production, use, and recycling in China. Meanwhile, the results also suggest the importance of monitoring the criticality of tungsten and other critical minerals from a dynamic and material cycle perspective.
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