Search

Lithium‐metal anodes (LMAs) are the ultimate choice for realizing high‐energy‐density batteries; however, its use is hindered by problematic Li growth in the form of dendrites. To alleviate dendritic Li growth, the preparation of LMAs with a lithiophilic current collector (CC) is effective; however, applying a lithiophilic CC to LMAs is still challenging due to the manufacturing complexity involved in the separate lithiophilic treatment and lithiation processes. Herein, a facile one‐pot LMA fabrication method by utilizing thiourea (TU) as a precursor is proposed. A lithiophilic Cu2S layer is formed on Cu foam (CF) by the in situ electrochemical oxidation of TU (CuxSCF), and the lithiation of CC is performed via subsequent Li electrodeposition (Li@CuxSCF). The Cu2S on CuxSCF can lead to uniform Li deposition by providing lithiophilic sites, and it is converted to form ionic‐conductive Li2S‐rich solid electrolyte interphase layer. Resultantly, CuxSCF significantly enhances the cycling performance of LMAs compared to CF. Specifically, a LiFePO4/Li@CuxSCF full‐cell lithium‐metal battery (LMB) with a low n/p ratio (1.6) exhibits capacity retention of 95.6% at 0.5 C (220 cycles) and can maintain 85.0% of initial capacity (425 cycles, n/p = 4) at 2.0 C. LMBs with LiNi0.6Co0.2Mn0.2 and LiNi0.8Co0.1Mn0.1 also exhibit improved electrochemical performance. [ABSTRACT FROM AUTHOR]

All‐solid‐state Li‐metal battery (ASSLB) represents advantageous energy storage system for automotive applications. For ASSLB, inorganic solid electrolyte is essential in determining safety and cycling performance. However, significant challenges persist in practical construction of ASSLB with optimized electrolyte. Specifically, electrolyte's structural instability influencing its electrochemical performance remains critical issue within typical operating temperatures for ASSLB in electric vehicles. Herein, this challenge is fundamentally addressed by substituting trace amount of lithium with cadmium, which lacks crystal field stabilization energy. This strategy of atomic interaction modification has induced electrolyte's structural distortion and electronic alteration by deliberately introducing disorder at local lithium sites. Li symmetric cell with cadmium‐substituted antiperovskite solid electrolyte exhibits outstanding critical current density of 11.5 mA cm−2 (5.75 mAh cm−2) and excellent stability for 3000 h at 10.0 mA cm−2 (5.0 mAh cm−2). This study highlights explicit research direction for breakthrough of ASSLB, focusing on understanding how local distortion affects complex inorganic materials. [ABSTRACT FROM AUTHOR]

Anode‐free manufacturing holds promise to enable high energy densities and lower Lithium (Li)‐metal solid‐state batteries (LMSSBs). Nevertheless, in contrast to thick Li foil (>50 µm), the stripping capacity of in situ‐formed Li (10–30 µm) is limited due to diminished creep flow, resulting in reduced accessible capacity. This study explores the correlation between stripping capacity and surface roughness of garnet Li7La3Zr2O12 (LLZO) solid electrolyte. The results reveal that stripping capacity can be enhanced through the surface modification of solid electrolytes. Additionally, this study scrutinizes the stripping behavior of in situ Li under intermittent‐current discharge conditions, which are more relevant to the operational conditions of electric vehicles (EVs). It is demonstrated that, when compared to constant‐current stripping, intermittent‐current stripping effectively suppresses void formation and enhances the stripping capacity of in situ Li by 40%. It is considered that the intermittent current inhibits the accumulation of Li vacancies, thereby delaying the void formation. These findings provide valuable insights into the development of high‐performance anode‐free LMSSBs for EVs. [ABSTRACT FROM AUTHOR]

Despite the relatively low stiffness of sulfide solid‐state electrolytes (SSEs), which makes them capable of better formability and accommodation for volume changes of active materials, the low fracture toughness (KIC) indicates a high susceptibility to fracture caused by electrochemo‐mechanical stresses. This susceptibility to mechanical damages and the subsequent lithium filament penetration, manifesting as micro‐short circuit events, seriously hinders the practical application of lithium metal in high‐energy‐density sulfide‐based all‐solid‐state lithium metal batteries (ASSLMBs). A full understanding of the stress evolution of Li metal anodes during cycling is key to decoding the mechanical damage‐induced micro‐short circuit behavior. Here, an operando and quantitative measurement of the stress evolution of an LTO/SSE/Li configuration all‐solid‐state battery (ASSB) operating with various parameters, including cell capacity and current density, is shown. Two micro‐short circuit modes and their corresponding mechanisms are revealed based on the electrochemo‐mechanical response of the Li metal anode. Furthermore, a finite element model (FEM) is used to explain this mechanical failure and a ′safety zone″ for the Li metal anode related to the ′internal stress″ is given. These findings provide new insight into the micro‐short circuit events induced by electrochemo‐mechanical damage in sulfide‐based ASSLMBs. [ABSTRACT FROM AUTHOR]

As a potential candidate for next‐generation energy storage systems, Li–O2 batteries (LOBs) with their attractive theoretical energy density have triggered great interest. However, tough issues of sluggish oxygen reduction reaction/oxygen evolution reaction (ORR/OER) kinetics, poor rechargeability, superoxide‐derived side reactions, and Li‐metal corrosion in LOBs limit their practical applications. Herein, a poly(2,2,2‐trifluoroethyl methacrylate) (PTFEMA) additive is introduced into the typical electrolyte, giving superior cycling performance to LOBs. Enabling strong solvation of Li+, PTFEMA regulates a uniform Li+ flow at the cathode and anode sides of LOBs. Induced by homogeneous Li+ flux and favorable adsorption with superoxide species, PTFEMA promotes superoxide transformation in the ORR and inhibits superoxide‐induced parasitic reactions. Uniform Li+ flux gives evenly‐distributed Li2O2 that can be completely decomposed during OER. In addition, PTFEMA protects Li‐metal against corrosion from O2, superoxide, and byproducts shuttle. Hence, accelerated ORR/OER kinetics, facilitated rechargeability, suppressed superoxide‐derived side reactions, and well‐protected Li‐metal can be simultaneously realized with PTFEMA, resulting in significantly enhanced electrochemical performance of LOBs. This electrolyte engineering involving facile multifunctional polymer additives provides a practical alternative to complex componential optimization toward commercial LOBs and gives insight to the understanding of uniform Li+ flux on reaction kinetics and reversibility. [ABSTRACT FROM AUTHOR]

Abstract With its high theoretical capacity, lithium (Li) metal is recognized as the most potential anode for realizing a high‐performance energy storage system. A series of questions (severe safety hazard, low Coulombic efficiency, short lifetime, etc.) induced by uncontrollable dendrites growth, unstable solid electrolyte interface layer, and large volume change, make practical application of Li‐metal anodes still a threshold. Due to their highly appealing properties, carbon‐based materials as hosts to composite with Li metal have been passionately investigated for improving the performance of Li‐metal batteries. This review displays an overview of the critical role of carbon‐based hosts for improving the comprehensive performance of Li‐metal anodes. Based on correlated mainstream models, the main failure mechanism of Li‐metal anodes is introduced. The advantages and strategies of carbon‐based hosts to address the corresponding challenges are generalized. The unique function, existing limitation, and recent research progress of key carbon‐based host materials for Li‐metal anodes are reviewed. Finally, a conclusion and an outlook for future research of carbon‐based hosts are presented. This review is dedicated to summarizing the advances of carbon‐based materials hosts in recent years and providing a reference for the further development of carbon‐based hosts for advanced Li‐metal anodes.

Interfacial instability between Li‐metal anode (LMA) and inorganic solid‐state electrolyte (SSE) is a critical issue in all‐solid‐state Li‐metal batteries (ASSLBs). Previous studies have focused on interface modification methodology to achieve long‐term cycling stability in ASSLBs. However, strategy establishment without an in‐depth understanding of the LMA–SSE interface is limited to a phenomenological solution. Also, the fact that rechargeable batteries are operated by behavior of charges inside electric field is frequently overlooked. Here, it is demonstrated for the first time that interface modeling based on energy band theory does effectively overcome the intrinsic vulnerability of SSE to LMA. The interfacial deterioration, due to undesirable electron transport from LMA to the SSE surface, is precluded by a titanium compound self‐induced interlayer (TSI), which forms an interfacial energy barrier. The Li symmetric cell with a TSI successfully maintains its constant overpotential over 1000 cycles and the significantly reduced impedance, whereas the cell having no interface modification exhibits erratic voltage profiles and is easily failed by repetitive charge–discharge process. This newly introduced approach is an informative tool to substantially reinforce the fundamental understanding of interfacial phenomena in all‐solid‐state batteries. Furthermore, rigorous stability requirements of automotive applications are expected to be fulfilled by the innovative interface modification. [ABSTRACT FROM AUTHOR]

Lithium (Li) metal is one of the most promising anode candidates for next‐generation rechargeable batteries with a high energy density because of its high theoretical specific capacity and low reduction potential. However, the growth of lithium dendrites causes intolerable safety risks and poor electrochemical performances. Limiting the migration of anions near the Li‐metal anode is regarded as an effective strategy to achieve uniform Li deposition and thus suppress the dendritic growth. Here, a metal‐organic frameworks based polyvinylidene fluoride‐hexafluoropropylene copolymer composite interlayer is designed and prepared through an in situ heat‐assisted method. Being guided and assisted by the anion‐shielded composite interlayer, a homogenous Li‐ion flux as well as a high Li‐ion transference number are achieved, which promotes the uniform and stable lithium deposition. At the same time, the robust composite interlayer is expected to suppress the growth of Li dendrites by its intrinsically high modulus (≈2.49 GPa). As a result, symmetrical batteries exhibit excellent cyclic stability for over 1600 h with functional composite interlayer. Furthermore, full cells with a commercial lithium iron phosphate cathode demonstrate remarkably enhanced cycling performance with a satisfying capacity retention of 96 % after 500 cycles. This work provides an effective strategy for the design and fabrication of functional composite interlayers to realize stable lithium metal anodes. [ABSTRACT FROM AUTHOR]

The growing demand for sustainable energy storage devices requires rechargeable lithium‐ion batteries (LIBs) with higher specific capacity and stricter safety standards. Ni‐rich layered transition metal oxides outperform other cathode materials and have attracted much attention in both academia and industry. Lithium‐ion batteries composed of Ni‐rich layered cathodes and graphite anodes (or Li‐metal anodes) are suitable to meet the energy requirements of the next generation of rechargeable batteries. However, the instability of Ni‐rich cathodes poses serious challenges to large‐scale commercialization. This paper reviews various degradation processes occurring at the cathode, anode, and electrolyte in Ni‐rich cathode‐based LIBs. It highlights the recent achievements in developing new stabilization strategies for the various battery components in future Ni‐rich cathode‐based LIBs. [ABSTRACT FROM AUTHOR]

With its high theoretical capacity, lithium (Li) metal is recognized as the most potential anode for realizing a high‐performance energy storage system. A series of questions (severe safety hazard, low Coulombic efficiency, short lifetime, etc.) induced by uncontrollable dendrites growth, unstable solid electrolyte interface layer, and large volume change, make practical application of Li‐metal anodes still a threshold. Due to their highly appealing properties, carbon‐based materials as hosts to composite with Li metal have been passionately investigated for improving the performance of Li‐metal batteries. This review displays an overview of the critical role of carbon‐based hosts for improving the comprehensive performance of Li‐metal anodes. Based on correlated mainstream models, the main failure mechanism of Li‐metal anodes is introduced. The advantages and strategies of carbon‐based hosts to address the corresponding challenges are generalized. The unique function, existing limitation, and recent research progress of key carbon‐based host materials for Li‐metal anodes are reviewed. Finally, a conclusion and an outlook for future research of carbon‐based hosts are presented. This review is dedicated to summarizing the advances of carbon‐based materials hosts in recent years and providing a reference for the further development of carbon‐based hosts for advanced Li‐metal anodes. [ABSTRACT FROM AUTHOR]

Lithium metal is regarded as the "Holy Grail" of anode materials due to its low electrochemical potential and high theoretical capacity. Unfortunately, its unstable solid electrolyte interphase (SEI) leads to low Coulombic efficiency (CE) and serious safety issues. Herein, a hybrid nanoscale polymeric protective film with tunable composition and improved stiffness is developed by incorporating aluminum crosslinkers into the polymer chains. The Li plating/stripping process is regulated through the protective coating and the dendrite growth is effectively suppressed. Promisingly, the protected Li can deliver stable performance for more than 350 h with a cycling capacity of 2 mAh cm−2 without a notable increase in overpotential. Moreover, a stable charge/discharge cycling in Li–O2 batteries with the protected Li can be maintained for more than 600 h. This work provides guidance on the rational design of electrode interfaces and opens up new opportunities for the fabrication of next‐generation energy storage systems. [ABSTRACT FROM AUTHOR]

A 3D host design for lithium (Li)-metal anodes can effectively accommodate volume changes and suppress Li dendrite growth; nonetheless, its practical applicability in energy-dense Li-metal batteries (LMBs) is plagued by excessive Li loading. Herein, we introduced eco- and human-friendly Se seeds into 3D carbon cloth (CC) to create a robust host for efficient Li deposition/stripping. The highly lithiophilic nano-Se endowed the Se-decorated CC (Se@CC) with perfect Li wettability for instantaneous Li infusion. At an optimal Li loading of 17 mg, the electrode delivered an unprecedentedly long life span of 5400 h with low overpotentials <36 mV at 1 mA cm -2 /1 mAh cm -2 and 1500 h at 5 mA cm -2 /5 mAh cm -2 . Furthermore, the uniform Se distribution and strong Li-Se binding allowed for further reduction in Li loading to 2 mg via direct Li electrodeposition. The corresponding LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811)-based full cell afforded a high capacity retention rate of 74.67% over 300 cycles at a low N/P ratio of 8.64. Finally, the initial anode-free LMB using a NCM811 cathode and a Se@CC anode current collector demonstrated a high electrode-level specific energy of 531 Wh kg -1 and consistently high CEs >99.7% over 200 cycles. This work highlights a high-performance host design with excellent tunability for practical high-energy-density LMBs.

Lithium-sulfur (Li-S) battery is a promising energy storage system due to its cost effectiveness and high energy density. However, formation of Li dendrites from Li metal anode and shuttle effect of lithium polysulfides (LiPSs) from S cathode impede its practical application. Herein, ultrafine ZnS nanodots are uniformly grown on 2D MXene nanosheets by a low-temperature (60 °C) hydrothermal method for the first time. Distinctively, the ZnS nanodot-decorated MXene nanosheets (ZnS/MXene) can be easily filtered to be a flexible and freestanding film in several minutes. The ZnS/MXene film can be used as a current collector for Li-metal anode to promote uniform Li deposition due to the superior lithiophilicity of ZnS nanodots. ZnS/MXene powders obtained by freeze drying can be used as separator decorator to address the shuttle effect of LiPSs due to their excellent adsorbability. Theoretical calculation proves that the existence of ZnS nanodots on MXene can obviously improve the adsorption ability of ZnS/MXene with Li + and LiPSs. Li-S full cells with composite Li-metal anode and modified separator exhibit remarkable rate and cycling performance. Other transition metal sulfides (CdS, CuS, etc.) can be also grown on 2D MXene nanosheets by the low-temperature hydrothermal strategy., (© 2023 Wiley-VCH GmbH.)

Lithium (Li) metal anodes (LMAs) are promising anode candidates for realizing high-energy-density batteries. However, the formation of unstable solid electrolyte interphase (SEI) layers on Li metal is harmful for stable Li cycling; hence, enhancing the physical/chemical properties of SEI layers is important for stabilizing LMAs. Herein, thiourea (TU, CH 4 N 2 S) is introduced as a new catalyzing agent for LiNO 3 reduction to form robust inorganic-rich SEI layers containing abundant Li 3 N. Due to the unique molecular structure of TU, the TU molecules adsorb on the Cu electrode by forming CuS bond and simultaneously form hydrogen bonding with other hydrogen bonds accepting species such as NO 3 - and TFSI - through its NH bonds, leading to their catalyzed reduction and hence the formation of inorganic-rich SEI layer with abundant Li 3 N, LiF, and Li 2 S/Li 2 S 2 . Particularly, this TU-modified SEI layer shows a lower film resistance and better uniformity compared to the electrochemically and naturally formed SEI layers, enabling planar Li growth without any other material treatments and hence improving the cyclic stability in Li/Cu half-cells and Li@Cu/LiFePO 4  full-cells., (© 2023 Wiley-VCH GmbH.)

Chemical and electrochemical instability of the Li metal interface with organic solvent has been a major impediment to use of Li-metal anodes for next-generation batteries. Here the character of Li surface degradation and the application of atomic layer deposition (ALD) as a protection layer to suppress the degradation are addressed. Using standard Li foil samples in organic solvent with and without in situ deposited ALD Al2O3 protective layers, results from in situ atomic force microscopy, mass spectrometry (including differential electrochemical mass spectrometry), X-ray Photoelectron Spectroscopy (XPS), and ex situ scanning electron microscopy/energy dispersive X-ray spectroscopy are reported. Despite the presence of a thin oxide/hydroxide/carbonate layer on the Li foil surface, degradation readily occurs in organic solvent, particularly at surface features such as ridges. Introduction of the ALD protective layer - deposited directly on this Li foil surface - dramatically suppresses the degradation. [ABSTRACT FROM AUTHOR]

The anode plays a critical role relating to the energy density in all-solid-state lithium batteries (ASLBs). Silicon (Si) and lithium (Li) metal are two of the most attractive anodes because of their ultrahigh theoretical capacities. However, most investigations focus on Li metal, leaving the great potential of Si underrated. This work investigates the stability, processability, and cost of Si anodes in ASLBs and compares them with Li metal. Moreover, single-crystal LiNi 0.8 Mn 0.1 Co 0.1 O 2 is stabilized with lithium silicate (Li 2 SiO x ) through a scalable sol-gel method. ASLBs with a cell-level energy density of 285 Wh kg -1 are obtained by sandwiching the Si anode, the thin sulfide solid-state electrolyte membrane, and the interface stabilized LiNi 0.8 Mn 0.1 Co 0.1 O 2 . The full cell delivers a high capacity of 145 mAh g -1 at C/3 and maintains stability for 1000 cycles. This work inspires commercialization of ASLBs on a large scale with exciting manufacturing lines for large-scale, safe, and economical energy storage., (© 2022 Wiley-VCH GmbH.)

Uncontrolled lithium dendrite growth and dramatic volume change during cycling have long been severely impeding the practical applications of Li metal as the ultimate anode. In this work, ultrathin MgF 2 nanosheets encapsulated inside nitrogen-doped graphene-like hollow nanospheres (MgF 2 NSs@NGHSs) are ingeniously fabricated to address these problems by a perfect combination of atomic layer deposition and chemical vapor deposition. The uniform and continuous Li-Mg solid-solution inner layer formed by the MgF 2 nanosheets can reduce the nucleation overpotential and induce selective deposition of Li into the cavities of the NGHSs. Furthermore, the Li deposition behavior and mechanism of the hybrid host are comprehensively explored by in situ optical microscopy at the macroscopic level, in situ transmission electron microscopy at the microscopic level, and theoretical calculations at the atomic level, respectively. Benefiting from a synergistic modulation strategy of nanosheet seed-induced nucleation and Li-confined growth, the designed composite demonstrates an endurance of 590 cycles for asymmetric cells and a lifespan over 1330 h for corresponding symmetric cells. When applied in LiFePO 4 full cells, it provides a reversible capacity of 90.6 mAh g -1 after 1000 cycles at 1 C., (© 2022 Wiley-VCH GmbH.)

Integrating solid-state electrolyte (SSE) into Li-metal anodes has demonstrated great promise to unleash the high energy density of rechargeable Li-metal batteries. However, fabricating a highly cyclable SSE/Li-metal anode remains a major challenge because the densification of the SSE is usually incompatible with the reactive Li metal. Here, a liquid-metal-derived hybrid solid electrolyte (HSE) is proposed, and a facile transfer technology to construct an artificial HSE on the Li metal is reported. By tuning the wettability of the transfer substrates, electron- and ion-conductive liquid metal is sandwiched between electron-insulating and ion-conductive LiF and oxides to form the HSE. The transfer technology renders the HSE continuous, dense, and uniform. The HSE, having high ion transport, electron shut-off, and mechanical strength, makes the composite anode deliver excellent cyclability for over 4000 h at 0.5 mA cm -2 and 1 mAh cm -2 in a symmetrical cell. When pairing with LiFePO 4 and sulfur cathodes, the HSE-coated Li metal dramatically enhances the performance of full cells. Therefore, this work demonstrates that tuning the interfacial wetting properties provides an alternate approach to build a robust solid electrolyte, which enables highly efficient Li-metal anodes., (© 2022 Wiley-VCH GmbH.)

The solid electrolyte interphase (SEI) dictates the cycling stability of lithium-metal batteries. Here, direct atomic imaging of the SEI's phase components and their spatial arrangement is achieved, using ultralow-dosage cryogenic transmission electron microscopy. The results show that, surprisingly, a lot of the deposited Li metal has amorphous atomic structure, likely due to carbon and oxygen impurities, and that crystalline lithium carbonate is not stable and readily decomposes when contacting the lithium metal. Lithium carbonate distributed in the outer SEI also continuously reacts with the electrolyte to produce gas, resulting in a dynamically evolving and porous SEI. Sulfur-containing additives cause the SEI to preferentially generate Li 2 SO 4 and overlithiated lithium sulfate and lithium oxide, which encapsulate lithium carbonate in the middle, limiting SEI thickening and enhancing battery life by a factor of ten. The spatial mapping of the SEI gradient amorphous (polymeric → inorganic → metallic) and crystalline phase components provides guidance for designing electrolyte additives., (© 2021 Wiley-VCH GmbH.)

An artificial lithium-nitrate (LiNO 3 )-rich layer (LN-RL) is developed to address dendritic lithium (Li) growth by a fusing-infusing strategy, in which LiNO 3 is loaded into stainless steel mesh and a Li-metal anode (LN-RL@Li) is obtained by casting this LN-RL onto Li foil. The LN-RL enables fast Li deposition kinetics in carbonates and endows LN-RL@Li with excellent cycleability. The underneath mechanism on the contribution of LN-RL is uncovered by detailed characterizations combining with theoretical simulations. The LN-RL promotes the desolvation and capacitive adsorption of Li ions and induces in-plane Li growth along the edges of preplated Li with planar morphology. The improved cycleability of LN-RL(@Li) is demonstrated by LiǁCu cell that presents a coulombic efficiency of 97.2% after 280 cycles and LiǁLi cell that proceeds over 1000 h at 0.5 mA cm -2 in carbonates. Additionally, the LiǁLiFePO 4 cell shows a capacity retention of 58% after 400 cycles at 1 C (1 C = 170 mA g -1 ), compared to the 35% after 180 cycles for the control. This work presents not only a promising strategy for practical applications of Li-metal batteries, but also a new understanding on the role of nitrate in Li plating/stripping kinetics., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Uncontrollable growth of Li dendrites and low utilization of active Li severely hinder its practical application. Construction of an artificial solid electrolyte interphase (SEI) on Li is demonstrated as one of the most effective ways to circumvent the above problems. Herein, a novel spray quenching method is developed in situ to fabricate an organic-inorganic composite SEI on Li metal. By spray quenching molten Li in a modified ether-based solution, a homogeneous and dense SEI consisting of organic matrix embedded with inorganic LiF and Li 3 N nanocrystallines (denoted as OIFN) is constructed on Li metal. Arising from high ionic conductivity and strong mechanical stability, the OIFN can not only effectively minimize the corrosion reaction of Li, but also greatly suppresses the dendrite growth. Accordingly, the OIFN-Li anode presents prominent electrochemical performance with an enhanced Coulombic efficiency of 98.15% for 200 cycles and a small hysteresis of <450 mV even at ultrahigh current density up to 10 mA cm -2 . More importantly, during the full cell test with limited Li source, a high utilization of Li up to 40.5% is achieved for the OIFN-Li anode. The work provides a brand-new route to fabricate advanced SEI on alkali metal for high-performance alkali-metal batteries., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The key bottlenecks hindering the practical implementations of lithium-metal anodes in high-energy-density rechargeable batteries are the uncontrolled dendrite growth and infinite volume changes during charging and discharging, which lead to short lifespan and catastrophic safety hazards. In principle, these problems can be mitigated or even solved by loading lithium into a high-surface-area, conductive, and lithiophilic porous scaffold. However, a suitable material that can synchronously host a large loading amount of lithium and endure a large current density has not been achieved. Here, a lithiophilic 3D nanoporous nitrogen-doped graphene as the sought-after scaffold material for lithium anodes is reported. The high surface area, large porosity, and high conductivity of the nanoporous graphene concede not only dendrite-free stripping/plating but also abundant open space accommodating volume fluctuations of lithium. This ingenious scaffold endows the lithium composite anode with a long-term cycling stability and ultrahigh rate capability, significantly improving the charge storage performance of high-energy-density rechargeable lithium batteries., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The Li-O 2 battery (LOB) is considered as a promising next-generation energy storage device because of its high theoretic specific energy. To make a practical rechargeable LOB, it is necessary to ensure the stability of the Li anode in an oxygen atmosphere, which is extremely challenging. In this work, an effective Li-anode protection strategy is reported by using boric acid (BA) as a solid electrolyte interface (SEI) forming additive. With the assistance of BA, a continuous and compact SEI film is formed on the Li-metal surface in an oxygen atmosphere, which can significantly reduce unwanted side reactions and suppress the growth of Li dendrites. Such an SEI film mainly consists of nanocrystalline lithium borates connected with amorphous borates, carbonates, fluorides, and some organic compounds. It is ionically conductive and mechanically stronger than conventional SEI layer in common Li-metal-based batteries. With these benefits, the cycle life of LOB is elongated more than sixfold., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Bendable energy-storage systems with high energy density are demanded for conformal electronics. Lithium-metal batteries including lithium-sulfur and lithium-oxygen cells have much higher theoretical energy density than lithium-ion batteries. Reckoned as the ideal anode, however, Li has many challenges when directly used, especially its tendency to form dendrite. Under bending conditions, the Li-dendrite growth can be further aggravated due to bending-induced local plastic deformation and Li-filaments pulverization. Here, the Li-metal anodes are made bending tolerant by integrating Li into bendable scaffolds such as reduced graphene oxide (r-GO) films. In the composites, the bending stress is largely dissipated by the scaffolds. The scaffolds have increased available surface for homogeneous Li plating and minimize volume fluctuation of Li electrodes during cycling. Significantly improved cycling performance under bending conditions is achieved. With the bending-tolerant r-GO/Li-metal anode, bendable lithium-sulfur and lithium-oxygen batteries with long cycling stability are realized. A bendable integrated solar cell-battery system charged by light with stable output and a series connected bendable battery pack with higher voltage is also demonstrated. It is anticipated that this bending-tolerant anode can be combined with further electrolytes and cathodes to develop new bendable energy systems., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

High-energy lithium-metal batteries are among the most promising candidates for next-generation energy storage systems. With a high specific capacity and a low reduction potential, the Li-metal anode has attracted extensive interest for decades. Dendritic Li formation, uncontrolled interfacial reactions, and huge volume effect are major hurdles to the commercial application of Li-metal anodes. Recent studies have shown that the performance and safety of Li-metal anodes can be significantly improved via organic electrolyte modification, Li-metal interface protection, Li-electrode framework design, separator coating, and so on. Superior to the liquid electrolytes, solid-state electrolytes are considered able to inhibit problematic Li dendrites and build safe solid Li-metal batteries. Inspired by the bright prospects of solid Li-metal batteries, increasing efforts have been devoted to overcoming the obstacles of solid Li-metal batteries, such as low ionic conductivity of the electrolyte and Li-electrolyte interfacial problems. Here, the approaches to protect Li-metal anodes from liquid batteries to solid-state batteries are outlined and analyzed in detail. Perspectives regarding the strategies for developing Li-metal anodes are discussed to facilitate the practical application of Li-metal batteries., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Substantial efforts are underway to develop all-solid-state Li batteries (SSLiBs) toward high safety, high power density, and high energy density. Garnet-structured solid-state electrolyte exhibits great promise for SSLiBs owing to its high Li-ion conductivity, wide potential window, and sufficient thermal/chemical stability. A major challenge of garnet is that the contact between the garnet and the Li-metal anodes is poor due to the rigidity of the garnet, which leads to limited active sites and large interfacial resistance. This study proposes a new methodology for reducing the garnet/Li-metal interfacial resistance by depositing a thin germanium (Ge) (20 nm) layer on garnet. By applying this approach, the garnet/Li-metal interfacial resistance decreases from ≈900 to ≈115 Ω cm 2 due to an alloying reaction between the Li metal and the Ge. In agreement with experiments, first-principles calculation confirms the good stability and improved wetting at the interface between the lithiated Ge layer and garnet. In this way, this unique Ge modification technique enables a stable cycling performance of a full cell of lithium metal, garnet electrolyte, and LiFePO 4 cathode at room temperature., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)