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All-carbon graphdiyne (GDY)-based materials have attracted extensive attention owing to their extraordinary structures and outstanding performance in electrochemical energy storage. Straightforward insights into the interfacial evolution at GDY electrode/electrolyte interface could crucially enrich the fundamental comprehensions and inspire targeted regulations. Herein

Gel polymer electrolytes (GPEs) are one of the promising candidates for high-energy-density quasi-solid-state lithium metal batteries (QSSLMBs), for their high ionic conductivity and excellent interfacial compatibility. The comprehension of dynamic evolution and structure-reactivity correlation at the GPE/Li interface becomes significant. Here, in situ electrochemical atomic force microscopy (EC-AFM) provides insights into the LiNO3-regulated micromechanism of the Li plating/stripping behavior upon cycles in GPE-based LMBs at nanoscale. The additive LiNO3 induces the formation of amorphous nitride SEI film and facilitates the Li+ ion diffusion. It stabilizes a compatible interface and regulates the Li nucleation/growth at steady kinetics. The deposited Li is in the shape of chunks and tightly compact. The Li dissolution shows favorable reversibility, which guarantees the cycling performance of LMBs. In situ AFM monitoring provides a deep understanding into the dynamic evolution of Li deposition/dissolution and the interphasial properties of tunable SEI film, regulating the rational design of electrolyte and interfacial establishment for GPE-based QSSLMBs.

Catalysts with two single-atom sites promote reversible conversion reactions between S and Li2S. The Co active site enhances the transformation kinetics of polysulfides upon charging, the Fe active site accelerates the transformation of Li2S to S8.

Micrometre-sized electrode materials have distinct advantages for battery applications in terms of energy density, processability, safety and cost. For the silicon monoxide anode that undergoes electrochemical alloying reaction with Li, the Li (de)intercalation by micron-sized active particles usually accompanies with a large volume variation, which pulverizes the particle structure and leads to rapidly faded storage performance. In this work, we proposed to stabilize the electrochemistry vs. Li of the micron-SiOx anode by forming a rigid-flexible bi-layer coating on the particle surface. The coating consists of pyrolysis carbon as the inner layer and polydopamine as the outer layer. While the inner layer guarantees high structural rigidity at particle surface and provides efficient pathway for electron conduction, the outer layer shows high flexibility for maintaining the integrity of micrometre-sized particles against drastic volume variation, and together they facilitate formation of stable solid electrolyte interface on the SiOx particles. A composite anode prepared by mixing the coated micron-SiOx with graphite delivered improved Li storage performance, and promised a high-capacity, long-life LiFePO4/SiOx-graphite pouch cell. Our strategy provides a general and feasible solution for building high-energy rechargeable batteries from micrometre-sized electrode materials with significant volume variation.

Safety concerns related to the abuse operation and thermal runaway are impeding the large-scale employment of high-energy-density rechargeable lithium batteries. Here, we report that by incorporating phosphorus-contained functional groups into a hydrocarbon-based polymer, a smart risk-responding polymer is prepared for effective mitigation of battery thermal runaway. At room temperature, the polymer is (electro)chemically compatible with electrodes, ensuring the stable battery operation. Upon thermal accumulation, the phosphorus-containing radicals spontaneously dissociate from the polymer skeleton and scavenge hydrogen and hydroxyl radicals to terminate the exothermic chain reaction, suppressing thermal generation at an early stage. With the smart risk-responding strategy, we demonstrate extending the time before thermal runaway for a 1.8-Ah Li-ion pouch cell by 100% (~9 hours) compared with common cells, creating a critical time window for safety management. The temperature-triggered automatic safety-responding strategy will improve high-energy-density battery tolerance against thermal abuse risk and pave the way to safer rechargeable batteries.

By applying a LiF-rich in situ solidified Li+-conductive interlayer, the interfacial contact and charge transfer stability between LPS and Li metal are notably improved, which leads to dendrite-free Li plating/stripping at the interface.

Lithium-sulfur batteries (LSBs) suffer from sluggish reaction kinetics of sulfur-containing species and loss of soluble polysulfides (PSs) during cycling, especially in the case of liquid electrolytes. Here, we improve the kinetics of sulfur species by decorating Mo2C nanoparticles on carbon nanotubes (CNTs) as the host for sulfur active mass. In addition, by use of gel polymer electrolytes (GPEs) derived from in situ polymerization of 1,3-dioxolane (DOL) to mitigate the diffusion of PSs and improve the stability of Li stripping/plating. As a result, the sulfur cathodes are endowed with enhanced initial specific capacity and suppressed dissolution of sulfur species. The cells with CNT/Mo2C/S cathodes and GPE exhibit excellent electrochemical performance. The anodes cycled with GPE show remarkably enhanced lithium plating-stripping behavior. Benefitting from the synergistic effect, LSBs with higher energy density and improved durability are obtained, demonstrating a new approach for developing high-performance quasi-solid-state Li metal batteries.

Lithium-sulfur batteries are promising candidates of energy storage devices. Both adjusting salt/solvent ratio and applying quasi-solid-state electrolytes are regarded as effective strategies to improve the lithium (Li) anode performance. However, reaction mechanisms and interfacial properties in quasi-solid-state lithium-sulfur (QSSLS) batteries with high salt concentration are not clear. Here we utilize in-situ characterizations and molecular dynamics simulations to unravel aforesaid mysteries, and construct relationships of electrolyte structure, interfacial behaviour and performance. The generation mechanism, formation process, and mechanical/chemical/electrochemical properties of the anion-derived solid electrolyte interphase (SEI) are deeply explored. Li deposition uniformity and dissolution reversibility are further tuned by the sustainable SEI. These straightforward evidences and deepgoing studies would guide the electrolyte design and interfacial engineering of QSSLS batteries.

The interfacial stability is highly responsible for the longevity and safety of sodium ion batteries (SIBs). However, the continuous solid-electrolyte interphase(SEI) growth would deteriorate its stability. Essentially, the SEI growth is associated with the electron leakage behavior, yet few efforts have tried to suppress the SEI growth, from the perspective of mitigating electron leakage. Herein, we built two kinds of SEI layers with distinct growth behaviors, via the additive strategy. The SEI physicochemical features (morphology and componential information) and SEI electronic properties (LUMO level, band gap, electron work function) were investigated elaborately. Experimental and calculational analyses showed that, the SEI layer with suppressed growth delivers both the low electron driving force and the high electron insulation ability. Thus, the electron leakage is mitigated, which restrains the continuous SEI growth, and favors the interface stability with enhanced electrochemical performance.

In Li-ion batteries, functional cosolvents could significantly improve the specific performance of the electrolyte, for example, the flame retardancy. In case the cosolvent shows strong Li

Solid-liquid hybrid electrolytes (SLHEs) are promising electrolyte candidates for Li-metal batteries. However, most of the components of SLHE are flammable, posing safety risks. Here, a non-flammable SLHE was proposed by in-situ encapsulating a flame-retardant liquid phosphate into a robust solid polycarbonate matrix. The in-situ solidified SLHE simultaneously features high Li+ conductivity (4.4 mS cm−1), Young's modulus (12.4 GPa), Li+ transference number (0.76) and a wide electrochemical window (0-4.9 V vs. Li+/Li), which help to effectively suppress dendrites and unfavorable side reactions at the anode and provide compatibility with the high-voltage cathode. By employing non-flammable SLHE, a prototype Li||LiNi0.8Co0.1Mn0.1O2 cell retains 87.7% of the initial capacity after 200 cycles, and the Ah level Li||LiNi0.8Co0.1Mn0.1O2 pouch cells showed enhanced safety by passing the nail test by authorized third parties. This study inspires the optimal design of SLHEs towards practical realization of safe and stable Li-metal batteries.

Rechargeable lithium-metal batteries with a cell-level specific energy of >400 Wh kg-1 are highly desired for next-generation storage applications, yet the research has been retarded by poor electrolyte-electrode compatibility and rigorous safety concerns. We demonstrate that by simply formulating the composition of conventional electrolytes, a hybrid electrolyte was constructed to ensure high (electro)chemical and thermal stability with both the Li-metal anode and the nickel-rich layered oxide cathodes. By employing the new electrolyte, Li∥LiNi0.6 Co0.2 Mn0.2 O2 cells show favorable cycling and rate performance, and a 10 Ah Li∥LiNi0.8 Co0.1 Mn0.1 O2 pouch cell demonstrates a practical specific energy of >450 Wh kg-1 . Our findings shed light on reasonable design principles for electrolyte and electrode/electrolyte interfaces toward practical realization of high-energy rechargeable batteries.

Composite electrolytes composed of a nanoceramic and polymer have been widely studied because of their high ionic conductivity, good Li-ion transference number, and excellent machinability, whereas the intrinsic reason for the improvement of performance is ambiguous. Herein, we have designed a functional polymer skeleton with different types of nanofiller to reveal the superiority of fast ion conductors in composite electrolyte. Three types of ceramics with different dielectric constants and Li-ion transfer ability were selected to prepare composite electrolytes, the composition, structure, and electrochemical performances of which were systematically investigated. It was found that the addition of fast ion conductive ceramics could provide a high Li-ion transference ability and decreased diffusion barrier because the additional pathways existed in the ceramic, which are revealed by experiment and density functional theory calculations. Benefiting from the superiority of fast ion conductor, Li-metal batteries with this advanced composite electrolyte exhibit an impressive cycling stability and enable a dendrite-free Li surface after cycling. Our work enriches the understanding of the function of fast ion conductors in composite electrolyte and guides the design for other high-performance composite electrolytes in rechargeable solid batteries.

Li+-conductive ceramic oxide electrolytes, such as garnet-structured Li7La3Zr2O12, have been considered as promising candidates for realizing the next-generation solid-state Li-metal batteries with high energy density. Practically, the ceramic pellets sintered at elevated temperatures are often provided with high stiffness yet low fracture toughness, making them too brittle for the manufacture of thin-film electrolytes and strain-involved operation of solid-state batteries. The ceramic powder, though provided with ductility, does not yield satisfactorily high Li+ conductivity due to poor ion conduction at the boundaries of ceramic particles. Here we show, with solid-state nuclear magnetic resonance, that a uniform conjugated polymer nanocoating formed on the surface of ceramic oxide particles builds pathways for Li+ conduction between adjacent particles in the unsintered ceramics. A tape-casted thin-film electrolyte (thickness

Li metal possesses a high theoretical specific capacity, high electronic conductivity, and a low electrochemical potential, making it a promising anode material for building next-generation rechargeable metal batteries. In case conventional liquid electrolytes were used, and the anode using Li metal has been hindered by unstable(electro)chemistry at Li/electrolyte interface and the accompanied dendrite issue. Specifically, for the Li-Se batteries, the dissolution and shuttle of polyselenide intermediates lead to the deposition of poorly-conductive species on the anode, which further aggravates the chemical environment at the anode. In this work, we proposed to stabilize the Li-Se electrochemistry by constructing a gel polymer electrolyte via in situ gelations of conventional ether-based electrolytes at room temperature. The results demonstrate that the in situ gelated electrolyte helps to build electrochemically stable electrode/electrolyte interfaces and promote the efficient transfer of charge carriers across the interface. Compared with the liquid electrolytes, the gelated electrolyte shows improved chemical compatibility with the Li metal anode, which effectively alleviates the unfavorable side reactions and dendrite formation at the anode/electrolyte interface, and the polyselenide shuttle from the cathode to the anode. As a result, the Li-Se battery shows a higher Coulombic efficiency and improved cycling performance.

Two-dimensional layered transition-metal dichalcogenides (TMDs) have attracted intense interest for their layer number-dependent electronic properties and have exciting potential for atomically thi...

Phenolic resin as a typical hard carbon precursor has attracted much attention towards sodium-ion batteries (SIBs) due to its high carbon yield and large reversible capacity. However, phenolic resin-based hard carbon commonly suffers from limited cycling performance and low initial Coulombic efficiency. Herein, we synthesized a hard carbon material from phenolic resin and manipulated its microstructure through tuning the pyrolysis temperature and pre-oxidation procedure. In particular, hard carbon materials with pre-oxidation deliver much improved capacity retention in contrast with those without pre-oxidation. Further analysis shows that with the pre-oxidation procedure, the enlarged d002 spacing, the much disordered microstructure, and the increased content of oxygen-containing functional groups are responsible for the performance enhancement of hard carbon. This study provides an in-depth understanding of the microstructure feature of phenolic resin-based hard carbon and opens up a feasible avenue for the design of high-performance carbon anode materials for their application in SIBs.

Due to high ionic conductivity, favorable mechanical plasticity, and non-flammable properties, inorganic sulfide solid electrolytes bring opportunities to the practical realization of rechargeable lithium–metal batteries with high energy, yet their use was impeded by an electrochemically unstable Li–electrolyte interface. Herein, we propose to address the issue via a Li+-conductive gel polymer interlayer, which is derived in situ from a conventional liquid ether electrolyte during the cell fabrication process. The gel polymer interlayer not only enables intimate solid–solid contact and uniform Li-ion flux at the heterointerface but also effectively inhibits interfacial reactions and Li dendrite growth. With improved interfacial stability, a Li–Li symmetric cell with the gel polymer interlayer demonstrates an ultra-stable Li plating/stripping performance of over 1300 hours at 0.1 mA cm−2 and 350 hours at 0.5 mA cm−2 at room temperature, and a high critical current density of >5 mA cm−2. This work offers general insights into a reasonable design of an anode/electrolyte interface for high-energy rechargeable Li–metal batteries.

Lithium metal batteries (LMBs) are regarded as the promising candidate for next-generation energy storage devices. Three-dimensional (3D) current collector is one of the effective anode materials for suppressing lithium (Li) dendrite and accommodating the variation of Li volume during the cycling. However, since the protruding 3D skeleton will also pierce the separator and cause catastrophic battery failure, the safety risk of short circuit still exists. The use of ceramic solid-state electrolyte (SSE) with high mechanical stability on the 3D anode can eliminate the danger of short circuit caused by Li dendrites or 3D skeleton. Nevertheless, in solid-state batteries, 3D anodes with highly electroactive areas suffer from considerable interface reactions and high interface impedance. Herein, we demonstrate a facile in-situ polymerized sealing (IPS) strategy to reconcile the 3D anode with ceramic SSE. The optimized battery configuration consists of 3D anode, in-situ polymerized interlayer and NASICON-type ceramic electrolyte of Li1.3Ti1.7Al0.3(PO4)3 (LATP). The in-situ polymerized interlayer not only significantly reduces the interfacial resistance between the 3D anode and LATP, but also encapsulates liquid electrolyte within the electrode for indispensable interface reactions and rapid Li+ transport. Resultingly, the symmetric cell of 3D Li | LATP | 3D Li delivered a long cycle life of 500 ​h. Moreover, this unique configuration can be paired with a LiNi0.6Co0.2Mn0.2O2 cathode and operate at room temperature, which exhibits excellent performances. This work provides a practical strategy for building safe and durable high-energy solid-state LMBs suitable for next-generation energy storage devices.

Chalcogen elements, such as sulfur (S), selenium (Se), tellurium (Te) and the interchalcogen compounds, have been studied extensively as cathode materials for the next-generation rechargeable lithium/sodium (Li/Na) batteries. The high energy output of the Li/Na-chalcogen battery originates from the two-electron conversion reaction between chalcogen cathode and alkali metal anode, through which both electrodes are able to deliver high theoretical capacities. The reaction also leads to parasitic reactions that deteriorate the chemical environment in the battery, and different cathode-anode combinations show their own features. In this article, we intend to discuss the fundamental conversion electrochemistry between chalcogen elements and alkali metals and its potential influence, either positive or negative, on the performance of batteries. The strategies to improve the conversion electrochemistry of chalcogen cathode are also reviewed to offer insights into the reasonable design of rechargeable Li/Na-chalcogen batteries.