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The selectivity of C2H4 and CH4 in CO2 electroreduction can be modulated on a Cu electrode by tannic acid modification, which jointly promotes H2O dissociation and stabilizes the intermediate.

The hydrophobic internal cavity and hydrophilic external surface of cyclodextrins (CDs) render promising electrochemical applications. Here, we report a comparative and mechanistic study on the use of CD molecules (α-, β-, and γ-CD) as electrolyte additives for rechargeable Zn batteries. The addition of α-CD in aqueous ZnSO

High-entropy materials are emerging electrocatalysts by integrating five or more elements into one single crystallographic phase to optimize the electronic structures and geometric environments. Here, a rocksalt-type high-entropy oxide Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O (HEO) is developed as an electrocatalyst towards the oxygen evolution reaction (OER). The obtained HEO features abundant cation and oxygen vacancies originating from the lattice mismatch of neighboring metal ions, together with enlarged Co/Ni‒O covalency due to the introduction of less electronegative Mg and Zn. As a result, the HEO exhibits superior intrinsic OER activities, delivering a turnover frequency (TOF) 15 and 84 folds that of CoO and NiO at 1.65 V, respectively. This study provides a mechanistic understanding of the enhanced OER on HEO and demonstrates the potential of high-entropy strategy in developing efficient oxygen electrocatalysts by elaborately incorporating low-cost elements with lower electronegativity.

Lithium nickel oxide (LiNiO2) cathode materials are featured with high capacity and low cost for rechargeable lithium-ion batteries but suffer from severe interface and structure instability. Here we report that rationally designed LiNiO2 via concentration-gradient yttrium modification exhibits alleviative side reactions and improved electrochemical performance. The LiNiO2 cathode with LiYO2-Y2O3 coating layer delivers a discharge capacity of 225 mAh g−1 with a high initial Coulombic efficiency of 93.4%. These improvements can be attributed to the formation of in-situ modified hybrid LiYO2-Y2O3 coating layer, which suppresses phase transformation, electrolyte oxidation and salt dissociation due to the formation of protective cathode electrolyte interface. The results indicate promising application of concentration-gradient yttrium coating as a facile approach to stabilize nickel-rich cathode materials.

Building stable, efficient, and low-cost oxygen evolution electrodes is of paramount importance but challenging for practical water electrolysis. Here, we report a robust electrode at high current ...

Hard carbon (HC) is a promising anode material for sodium-ion batteries, yet still suffers from low initial Coulombic efficiency (ICE) and unstable solid electrolyte interphase (SEI). Herein, sodium diphenyl ketone (Na-DK) is applied to realize dual-function presodiation for HC anodes. It compensates the irreversible Na uptake at the oxygen-containing functional groups and reacts with carbon defects of five/seven-membered rings for quasi-metallic sodium in HC. The as-formed sodium induces robust NaF-rich SEI on HC in 1.0 M NaPF

Metallic zinc (Zn) is an attractive anode material to use for building an aqueous battery but suffers from dendritic growth and water-induced corrosion. Herein, we report the use of vanillin as a bifunctional additive in aqueous electrolyte to stabilize the Zn electrochemistry. Computational, spectroscopic, and electrochemical studies suggest that vanillin molecules preferentially absorb in parallel on the Zn surface to homogenize the Zn2+ plating and favorably coordinate with Zn2+ to weaken the solvation interaction between H2O and Zn2+, resulting in a compact, dendrite-free Zn deposition and a stable electrode-electrolyte interface with suppressed hydrogen evolution and hydroxide sulfate formation. In the formulated 2 M ZnSO4 electrolyte with 5 mM vanillin, the Zn anode sustains high areal capacity (10 mAh cm-2 at 1 mA cm-2) and remarkable cycling stability (1 mAh cm-2 for 1000 h) in a Zn|Zn cell and high average Coulombic efficiency (99.8%) in a Zn|Cu cell, significantly outperforming the cells without vanillin. Furthermore, the vanillin additive supports stable operation of full Zn|V2O5 batteries and is readily generalized to a Zn(CF3SO3)2-based electrolyte. This work offers a facile and cost-effective strategy of electrolyte design to enable high-performance aqueous Zn batteries.

Non-noble transition metal complexes have attracted growing interest as efficient electrocatalysts for oxygen reduction reaction (ORR) while their activities still lack rational and effective regulation. Herein, we propose a d-π conjugation strategy for rough and fine tuning of ORR activity of TM-BTA (TM=Mn/Fe/Co/Ni/Cu, BTA=1,2,4,5-benzenetetramine) coordination polymers. By first-principle calculations, we elucidate that the strong d-π conjugation elevates the dxz /dyz orbitals of TM centers to enhance intermediate adsorption and strengthens the electronic modulation effect from substitute groups on ligands. Based on this strategy, Co-TABQ (tetramino benzoquinone) is found to approach the top of ORR activity volcano. The synthesized Co-TABQ with atomically distributed Co on carbon nanotubes exhibits a half-wave potential of 0.85 V and a specific current of 127 mA mgmetal -1 at 0.8 V, outperforming the benchmark Pt/C. The high activity, low peroxide yield, and considerable durability of Co-BTA and Co-TABQ promise their application in oxygen electrocatalysis. This study provides mechanistic insight into the rational design of transition metal complex catalysts.

A non-flammable, dilute, and hydrous organic electrolyte can homogenize Zn plating/stripping, suppress water decomposition, and form organic–inorganic hybrid interphase on Zn, thus contributing to highly reversible Zn metal batteries.

Surface strain engineering is considered as an effective strategy to promote the electrocatalytic properties of noble metal nanocrystals. Herein, we construct a dual-phase palladium-copper (DP-PdCu) bimetallic electrocatalyst with remarkable biaxial strain via a one-pot wet-chemical approach for formic acid oxidation. The biaxial strain originates from the lattice mismatch between the disordered face-centered cubic (FCC) phase and ordered body-centered cubic (BCC) phase in each of DP-PdCu nanoparticles. The proportion of FCC and BCC phases and size of PdCu nanoparticles are dependent on the addition amount of capping agent, cetyltrimethylammonium bromide (CTAB). Density functional theory calculations reveal the downshift of d-band center of Pd atoms due to the interfacial strain, which weakens the adsorption strength of undesired intermediates. These merit the DP-PdCu catalyst with superior mass activity of 0.55 A·mgPd-1 and specific activity of 1.91 mA·cmPd-2 toward formic acid oxidation, outperforming the single FCC/BCC PdCu and commercial Pd/C catalysts. This will provide new insights into the structure design of high-performance electrocatalysts via strain engineering.

Metallic zinc is attractive anode material of rechargeable aqueous Zn-based batteries due to its ambient stability, high volumetric capacity, and abundant reserves. Nonetheless, Zn anodes suffer from issues such as low coulombic efficiency (CE), large polarization and dendrite formation. Herein, uniform Zn electrodeposition is reported on carbon substrates by selective nitrogen doping. Combined experimental and theoretical investigations demonstrate that pyrrolic and pyridinic nitrogen doped in carbon play beneficial effect as zinc-philic sites to direct nucleation and growth of metallic Zn, while negligible effect is observed for graphite nitrogen in Zn plating. The carbon cloth with modified amount of doped pyrrolic and pyridinic nitrogen stabilizes Zn plating/stripping with 99.3% CE after 300 cycles and significantly increases the deliverable capacity at high depth of charge and discharge compared to undoped carbon substrate and Zn foil. This work provides a better understanding of heteroatom doping effect in design and preparation of stable 3D carbon-supported zinc anode.

Ni-rich layered oxides (NRLOs) and Li-rich layered oxides (LRLOs) have been considered as promising next-generation cathode materials for lithium ion batteries (LIBs) due to their high energy density, low cost, and environmental friendliness. However, these two layered oxides suffer from similar problems like capacity fading and different obstacles such as thermal runaway for NRLOs and voltage decay for LRLOs. Understanding the similarities and differences of their challenges and strategies at multiple scales plays a paramount role in the cathode development of advanced LIBs. Herein, we provide a comprehensive review of state-of-the-art progress made in NRLOs and LRLOs based on multi-scale insights into electrons/ions, crystals, particles, electrodes and cells. For NRLOs, issues like structure disorder, cracks, interfacial degradation and thermal runaway are elaborately discussed. Superexchange interaction and magnetic frustration are blamed for structure disorder while strains induced by universal structural collapse result in issues like cracks. For LRLOs, we present an overview of the origin of high capacity followed by local crystal structure, and the root of voltage hysteresis/decay, which are ascribed to reduced valence of transition metal ions, phase transformation, strains, and microstructure degradation. We then discuss failure mechanism in full cells with NRLO cathode and commercial challenges of LRLOs. Moreover, strategies to improve the performance of NRLOs and LRLOs from different scales such as ion-doping, microstructure designs, particle modifications, and electrode/electrolyte interface engineering are summarized. Dopants like Na, Mg and Zr, delicate gradient concentration design, coatings like spinel LiNi0.5Mn1.5O4 or Li3PO4 and novel electrolyte formulas are highly desired. Developing single crystals for NRLOs and new crystallographic structure or heterostructure for LRLOs are also emphasized. Finally, remaining challenges and perspectives are outlined for the development of NRLOs and LRLOs. This review offers fundamental understanding and future perspectives towards high-performance cathodes for next-generation LIBs.

Engineering a stable solid electrolyte interphase (SEI) is one of the critical maneuvers in improving the performance of a lithium anode for high-energy-density rechargeable lithium batteries. Herein, we build a fluorinated lithium/sodium hybrid interphase via a facile electroless electrolyte-soaking approach to stabilize the repeated plating/stripping of lithium metal. Jointed experimental and computational characterizations reveal that the fluorinated hybrid SEI mainly consisting of NaF, LiF, LixPOyFz, and organic components features a mosaic polycrystalline structure with enriched grain boundaries and superior interfacial properties toward Li. This LiF/NaF hybrid SEI exhibits improved ionic conductivity and mechanical strength in comparison to the SEI without NaF. Remarkably, the fluorinated hybrid SEI enables an extended dendrite-free cycling of metallic Li over 1300 h at a high areal capacity of 10 mAh cm-2 in symmetrical cells. Furthermore, full cells based on the LiFePO4 cathode and hybrid SEI-protected Li anode sustain long-term stability and good capacity retention (96.70% after 200 cycles) at 0.5 C. This work could provide a new avenue for designing robust multifunctional SEI to upgrade the metallic lithium anode.

Metallic lithium is one of the most promising anode materials to build next generation electrochemical power sources such as Li-air, Li-sulfur, and solid-state lithium batteries. The implementation of rechargeable Li-based batteries is plagued by issues including dendrites, pulverization, and an unstable solid electrolyte interface (SEI). Herein, we report the use of nanostructured CuO in situ grown on commercial copper foil (CuO@Cu) via chemical etching as a Li-reservoir substrate to stabilize SEI formation and Li stripping/plating. The lithiophilic interconnected CuO layer enhances electrolyte wettability. Besides, a mechanically stable Li2O- and LiF-rich SEI is generated on CuO@Cu during initial discharge, which permits dense and uniform lithium deposition upon subsequent cycling. Compared with bare Cu, the CuO@Cu electrode exhibits superior performance in terms of Coulombic efficiency, discharge/charge overpotentials, and cyclability. By pairing with the Li-CuO@Cu anodes, full cells with LiFePO4 and LiNi1/3Mn1/3Co1/3O2 cathodes sustain 300 cycles with 98.8% capacity retention at 1 C and deliver a specific capacity of 80 mAh g-1 at 10 C, respectively. This work would shed light on the design of advanced current collectors with SEI modulation to upgrade lithium anodes.

This paper traces the history and usage of the theory of Sinicisation in western and Chinese scholarship, and discusses the intellectual trends underlying the different discourses in which the theory has been adopted. Since early 20th Century, the theory of “Sinicisation” has evolved and was adopted into three distinct historiographical discourses to construct different arguments. The first discourse is about the historical acculturation of border peoples and assimilation of domestic peoples to Chinese language, culture and economic life; the second one argues an inherent superiority in Chinese culture specifically produced cultural change across eastern Eurasia to promote nationalism; the third discourse emphasizes the diversity and mixture of the people living inside historical and contemporary China to construct and stabilise the polity. Every discourse rooted in its own intellectual trend, and also faces different criticism. Followed with examining criticisms of Sinicisation since the 1950s, this paper concludes by discussing the relationships of the three discourses of Sinicisation.

The development of clean and sustainable energy depends largely on electrocatalysis-driven technologies. Because of this, tremendous efforts have been devoted to the search for efficient electrocatalysts to reduce the overpotential and increase the selectivity of electrochemical reactions. Of the various approaches, electrochemical tuning is seen as a promising technique to controllably tune the properties of catalytic materials under mild conditions. Based on this, this review will present representative electrochemical tuning methodologies involving insertion and conversion reactions in batteries as well as in situ electrode modulation during electrocatalysis processes. This review will first provide an introduction of electrochemical tuning strategies from the perspective of reactions and devices. Subsequently, this review will present comprehensive discussions on recent advancements in the modulation of various electrocatalyst properties, including electronic structure, crystalline phase, lattice strain and dimensional size, all of which significantly impact corresponding intrinsic activity and active site exposure. This review will also highlight the merits, challenges and issues of electrochemical tuning and propose promising directions in the exploration of corresponding methods in the design and enhancement of electrocatalysts for future energy applications.

Defects engineering is an efficient strategy to enhance the performance of electrode materials by modulating the local electronic structure but usually requires costly and complicated processing. H...

Aqueous zinc ion batteries employing metallic zinc anodes and aqueous electrolytes are highly attractive electrochemical energy storage devices owing to their cost effectiveness, intrinsic safety, elemental abundance and competitive gravimetric energy density. Compared with other cathode materials, vanadium-based compounds feature advantages such as higher capacity, higher power density and longer cycle life. Here, a comprehensive review is presented on recent advances of vanadium-based cathodes, focusing on the correlation between the structures and electrode performances as well as energy-storage mechanisms. The structure and electrochemical properties of vanadium-based cathode materials are discussed by categorizing Zn2+ diffusion channels including one-dimensional tunnels, two-dimensional planes, three-dimensional interpenetrating networks and zero-dimensional diffusion channels. Furthermore, the remaining issues of vanadium-based cathodes are highlighted and promising performance-enhancement strategies are overviewed from aspects such as lattice control, vacancy/defect engineering, and pre-intercalation of cations and/or molecules.

Enhancing the zinc ion storage ability of the existing cathodes is an important research field. Constructing the heterostructure is a promising and effective strategy. Interestingly, for oxygen-free cathodes, a nano-depth heterostructure layer will inevitably form on their surface when exposed to air. However, only the near-surface heterostructure interface cannot change their intrinsic zinc storage ability. Theoretically speaking, via constructing the bulk-type heterostructure with enough interfaces and grain boundaries, the intrinsic zinc storage ability of bulk cathodes can be effectively improved. Here, as a proof of concept, an operando conversion method to construct VS4/V2O3 heterostructures enabled by the extrinsic adsorbed oxygen is proposed. The successful preparation of VS4/V2O3 heterostructures is demonstrated via various characterization studies and analyses including X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, etc. Meanwhile, the obtained VS4/V2O3 heterostructures deliver an enhanced zinc ion storage capacity of 164 mA h g−1, rate performance and cycle stability. This operando construction approach enabled by extrinsic adsorbed oxygen provides a novel strategy to fabricate the functional heterostructure-based cathodes for multivalent ion batteries with high performance.

We report a facile, in situ method to prepare interpenetrating networks of single-ion conductive polymer electrolytes (IN-SCPEs) for solid-state lithium metal batteries. IN-SCPEs were synthesized b...

Ni-rich layered oxides with chemical formula of LiNixCoyMnzO2 or LiNixCoyAlzO2 (x + y + z = 1, x ≥ 0.6) have been considered as promising cathode materials for lithium-ion batteries (LIBs) because of their high specific capacity (≥180 mAh g–1) and acceptable manufacture cost. However, the problems associated with high Ni content severely restrict their large-scale applications. In this review, we summarize the recent advances in Ni-rich layered oxide particle materials for LIBs. We begin with the introduction of the structure, redox mechanism, and problems of Ni-rich layered oxides, mainly including residual lithium compounds, gas evolution, rock-salt phase formation, microcrack of particles, dissolution of transition-metal ions, and thermal runaway. Then, four strategies (primary particle engineering, surface coating, doping, concentration gradient design) toward solving the problems of Ni-rich layered oxides will be systematically discussed with the emphasis on structure-performance relationships. To achieve satisfied comprehensive performance and accelerate large-scale applications of Ni-rich layered oxides, the combination of two or more strategies (particle engineering and surface/bulk stabilization techniques) with synergistic effects is necessary in future works. This review would promote further research and application of high-performance Ni-rich layered oxide particle materials for LIBs.