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Rechargeable magnesium batteries (RMBs) have the potentials in terms of high energy density, resource abundancy and safety beyond current lithium‐ion batteries. However, the bare Mg metal electrode is prone to be passivated by solvents, suffering from the extremely high overpotential and short life during cycling. Herein, a facile chloride‐free solution pretreatment method for Mg anode is developed to construct the fluoride‐rich artificial interphase. Driven by the strong‐Lewis‐acidity trifluoromethanesulfonate anion, the interphase consisting of magnesiophilic and fluoride‐rich components are constructed by the substitution reaction of Mg metal with antimony trifluoride. The formed porous Sb‐based skeletons can uniform the electric‐field distribution and Mg ions flux at anode side, inducing the self‐adapting dendrite‐free Mg deposition even under large current density. The generated alloyable metal fluoride enables to lower the desolvation energy barrier for Mg ions and sustainedly release metallic antimony to compensate for the potentially invalid magnesiophilic sites during cycling. Therefore the symmetric cells with modified Mg anodes achieve the excellent cycling over 2000 h at 1 mA cm−2 and under a high areal capacity of 5 mAh cm−2. The full cells with CuS cathodes exhibit a superior high voltage stability (2.6 V vs Mg/Mg2+) and high coulombic efficiency close to 100%. [ABSTRACT FROM AUTHOR]

Magnesium metal batteries (MMBs) currently face challenges suffering from severe Mg metal passivation and extremely high overpotential in conventional electrolytes. Herein, a strategy of using a low‐cost deep eutectic solution (DES) is proposed to modify Mg anode with the monolithic and compact coating of a MgCl2‐Al‐MgCl2 sandwich structure, enabling the stable and reversible Mg plating–stripping behavior. An organic/nanocrystal hybrid interphase is in‐situ built through a facile Mg‐Al displacement reaction between aluminum‐chloro clusters and Mg in AlCl3/Et3NHCl solution, and it can effectively minimize the adverse interfacial passivation reaction and surface diffusion barrier, affording the high ion‐conduction and electronic insulation. This DES‐assisted method guarantees a highly reversible cycling of Mg metal anode (over 5000 h at 0.1 mA cm−2 and 400 h at 2.0 mAh cm−2) in Mg(TFSI)2/DME electrolyte with the improved interfacial kinetics and low overpotential. Even at a much higher current density of 1 mA cm−2, the overpotential only undergoes a slight increase from 0.2 V (at 0.1 mA cm−2) to 0.23 V. The corresponding full cells with CuS and phenanthraquinone cathodes deliver satisfactory cyclic performance. The DES modification strategy provides a new solution to the design of robust and conductive solid electrolyte interphase for achieving high‐voltage and durable MMBs. [ABSTRACT FROM AUTHOR]

High‐rate anode material is the kernel of developing fast‐charging lithium ion batteries (LIBs). T–Nb2O5, well‐known for its "room and pillar" structure and bulk pseudocapacitive effect, is expected to enable the fast lithium (de)intercalation. But this property is still limited by the low electronic conductivity or insufficient wiring manner. Herein, a strategy of triple conductive wiring through electron doping, chelation coating, and electrochemical conversion inside the microsized porous spheres consisting of dendrite‐like T–Nb2O5 primary particles is proposed to achieve the fast‐charging and durable anodes for LIBs. The penetrative implanting of conformal carbon coating (derivative from polydopamine chelate) and NbO domains (induced by excess discharging) reinforces the global supply of electronically conductive wires, apart from those from Co/Mn heteroatom or O vacancy doping. The polydopamine etching on T–Nb2O5 spheres promotes their evolution into fluffy morphology with better electrolyte infiltration. The synergic electron and ion wiring at different scales endow the modified T–Nb2O5 anode with ultralong cycling life (143 mAh g−1 at 1 A g−1 after 8500 cycles) and high‐rate performance (144.1 mAh g−1 at 10.0 A g−1). The permeation of multiple electron wires also enables a high mass loading of T–Nb2O5 (4.5 mg cm−2) with a high areal capacity of 0.668 mAh cm−2 even after 150 cycles. [ABSTRACT FROM AUTHOR]

Metastable orthorhombic niobium pentoxide (T‐Nb2O5) is a promising anode to fulfill the requirements for high‐rate Li‐ion batteries (LIBs). Stoichiometric T‐Nb2O5 is plagued by low electric conductivity and particle pulverization after repeated charge/discharge processes. In this work, oxygen vacancies are implanted into T‐Nb2O5 particles via acid immersion of Nb2O5·nH2O with the formation of Lewis acid sites. The multiple characterizations and simulations reveal the lengthening of NbO bonds, and the transformation from NbO7 pentagonal bipyramids and NbO6 tetragonal bipyramids in T‐Nb2O5−x. The enrichment of oxygen vacancies endows T‐Nb2O5−x with higher electric conductivity, better electrochemical kinetics, larger pseudocapacitive contribution. O‐doped graphitic C3N4 is creatively proposed as a trace oxygen pump to repair excessive oxygen vacancies, and it also serves as a sacrifice template for Nb2O5−x growth to construct a porous and monolithic electrode network. Defect‐modulated Nb2O5−x displays extraordinary cycling stability (164 mAh g−1 at 5 C after 1100 cycles), high capacity retention (104 mAh g−1) at an ultrahigh rate (25 C), and large areal capacity (0.74 mAh cm−2) under high mass loading (4 mg cm−2). The practical prospect is proved by Nb2O5−x/LiNi0.8Co0.1Mn0.1O2 full cells with high average platform (2.12 V) and high specific capacity (229 mAh g−1). The oxygen‐defect modulation strategy on oxide anodes provides an alternative solution to fast‐charging and durable LIBs. [ABSTRACT FROM AUTHOR]

High‐capacity silicon anodes have attracted tremendous interest for next‐generation lithium‐ion batteries (LIBs). However, its further application is limited by the large volume expansion during cycling. Designing nanostructured silicon is an effective strategy to acquire high‐performance anodes, but it will face problems of high cost and poor coulombic efficiency. As a comparison, surface modification of micron silicon is more economically viable. Herein, a novel route is proposed to synthesize metal‐chelated biomimetic polyelectrolyte as a powerful binder, which wraps micron silicon particles in a thin Fe3+–polydopamine (PDA) layer with a thickness of 2–5 nm. The introduced Fe3+ can form powerful metal‐chelated bonds with PDA at appropriate hydrothermal temperature (160 °C). As a result, the mechanical strength of the protective layer is enhanced and the electrochemical activity of micron silicon is improved. Meanwhile, the 3D crosslinking structure formed through the esterification between the elastic polymer layer and polyacrylic acid (PAA) further guarantees the structural stability of anodes. Batteries using Si@Fe3+–PDA–160/PAA anode exhibit excellent cycling performance with stable capacity of 2000 mAh g−1 over 200 cycles at 0.5 C and high capacity retention ratio of 80% after 100 cycles at 0.1 C. [ABSTRACT FROM AUTHOR]

Building porosity in monolithic materials is highly desired to design 3D electrodes, however ex-situ introduction or in-situ generation of nano-scale sacrificial template is still a great challenge. Here Al-Si eutectic droplet templates are uniformly injected into bulk Si through Al-induced solid-solid convection to construct a highly porous Si framework. This process is concomitant with process-inherent conformal coating of ion-conductive oxide. Such an all-in-one method has generated a (continuously processed) high-capacity Si anode integrating longevity and stable electrolyte-anode diaphragm for Li-ion batteries (e.g. a reversible capacity as large as ~1800 mAh/g or ~350 μAh/cm2-μm with a CE of ~99% at 0.1 C after long-term 400 cycles). [ABSTRACT FROM AUTHOR]

[Display omitted] • A drip coating method is proposed to construct a gradient structure on Mg surface. • The upper PTHF network with rich Mg-Cl moieties allows fast Mg-ion transport. • The lower Sn-based magnesophilic domains provide abundant Mg deposition sites. • The modified Mg anode can withstand record-high current density and capacity. • The Mg/CuS full cells realize high capacity and stable cycling at high rate. Magnesium metal batteries (MMBs) are being considered as promising candidate for next generation batteries, benefiting from the high specific capacity, low redox potential and abundant earth reserve of Mg anode. However, the Mg anode is prone to be passivated from the side reactions between Mg metal and conventional electrolyte, leading to high polarization and poor kinetics. To solve this problem, we propose a facile drip coating method to construct a polymer-alloy hybrid layer on Mg surface, with a polymerized tetrahydrofuran (PTHF) network crosslinked with Mg-Cl and Sn-Cl complexes and a metallic layer with Sn and Mg-Sn domains from top to bottom. This gradient structure is a mixed electron–ion conductor, and the upper PTHF network with rich Mg-Cl moieties allows fast Mg-ion transport and its flux homogenization, while the lower Sn-based magnesophilic domains provide abundant Mg deposition sites with low nucleation and migration barriers, guaranteeing the uniform Mg plating and stripping. This protection layer enables the ultrahigh exchange current density and low interfacial resistance compared with the natural passivation layer of Mg metal. Thus, the modified Mg anode possess the much lower overpotential (300 mV) and ultralong cycling stability (over 3200 h) at 3 mA cm−2 and 3 mAh cm−2, and can even withstand the record-high current density (6 mA cm−2) and area capacity (6 mAh cm−2). When the modified Mg couples with CuS conversion cathode, the corresponding full cells still realize the high reversible capacity over 200 mAh-g-1 and stable cycling at the high current density (500 mA g−1) without any electrolyte addition. This method effectively promotes the possibility of practical application of high-rate and durable MMBs in the future. [ABSTRACT FROM AUTHOR]

Li 3 P-VP nanocomposite has been formed by a homemade pulsed laser deposition route and its electrochemical characteristic with lithium is reported for the first time. It displays high lithium storage capability as electrode material for secondary lithium ion batteries. The Li 3 P-VP nanocomposite exhibits high specific discharge capacity of 1040.4 mAh g−1 between 0.01 and 4.0 V and the specific capacity can still maintain 95% after 50 cycles. Ex situ transmission electron microscopy reveals that VP 2 is generated from Li 3 P and VP after the first charging process to 4.0 V, while Li 3 P and V are found to be the final discharge products. In the recharging process, VP and VP 2 are formed as the delithiated products. Unlabelled Image • Li 3 P-VP nanocomposite thin film was fabricated by PLD. • High capacity of 1040.4 mAh g−1 was achieved and 95% was kept after 50 cycles. • VP 2 was generated from Li 3 P and VP after the first charging process to 4.0 V. • Reversible conversion mechanism to V and Li 3 P was suggested for VP-VP 2. [ABSTRACT FROM AUTHOR]

Abstract As the most promising anode material for next-generation Li batteries, Li metal never loses the academic attention due to its inherent superiority in high theoretical capacity and low redox potential. However, Li dendrites formed during cycling stubbornly hinder the pace of commercializing high-energy-density Li metal batteries. Here sericin endowed with abundant lithiophilic and anionphilic functional groups on its polypeptide chain is proposed as a conformal protective coating on both Cu and Li metal anodes. The resulting increase of Li-ion transference number (as high as 0.876) and mitigation of tip effect are favorable for the homogeneous Li deposition in island-like or lateral growth mode at electrode/electrolyte interface. Long cycle life (335 cycles) and high Coulombic efficiency (98%) are obtained in sericin decorated Li/Cu cells. Even under extremely high current density of 10 mA cm−2 based on a large capacity of 5 mAh cm−2, the sericin decorated Li anode also enables a superior cycle stability (160 cycles) in the symmetric cells. The conformal sericin coating effectively inhibits the corrosion of air to Li metal. Sericin modified Li-S batteries exhibit greatly enhanced rate performance (452.8 mAh g−1 at 5 C) and cycling performance (667.8 mAh g−1 after 520 cycles at 1 C). Graphical abstract Image 1 Highlights • Sericin is proposed as a conformal protective coating on both Cu and Li metal anodes. • Under 10 mA cm−2, the sericin decorated Li anode enables a superior cycle stability. • The conformal sericin coating effectively inhibits the corrosion of air to Li metal. • Sericin modified Li-S batteries exhibit enhanced rate and cycling performance. [ABSTRACT FROM AUTHOR]