Solid‐state lithium (Li) batteries using solid electrolytes and Li anodes are highly desirable because of their high energy densities and intrinsic safety. However, low ambient‐temperature ...conductivity and poor interface compatibility of solid electrolytes as well as Li dendrite formation cause large polarization and poor cycling stability. Herein, a high transference number intercalated composite solid electrolyte (CSE) is prepared by the combination of a solution‐casting and hot‐pressing method using layered lithium montmorillonite, poly(ethylene carbonate), lithium bis(fluorosulfonyl)imide, high‐voltage fluoroethylene carbonate additive, and poly(tetrafluoroethylene) binder. The electrolyte presents high ionic conductivity (3.5 × 10−4 S cm−1), a wide electrochemical window (4.6 V vs Li+/Li), and high ionic transference number (0.83) at 25 °C. In addition, a 3D Li anode is also fabricated via a facile thermal infusion strategy. The synergistic effect of high transference number intercalated electrolyte and 3D Li anode is more favorable to suppress Li dendrites in a working battery. The solid‐state batteries based on LiFePO4 (Al2O3 @ LiNi0.5Co0.2Mn0.3O2), CSE, and 3D Li deliver admirable cycling stability with discharge capacity 145.9 mAh g−1 (150.7 mAh g−1) and capacity retention 91.9% after 200 cycles at 0.5 C (92.0% after 100 cycles at 0.2 C) at 25 °C. This work affords a splendid strategy for high‐performance solid‐state battery.
The intercalated composite solid electrolyte presents a large ionic conductivity and high ionic transference number. The synergistic effect of the high transference number intercalated electrolytes and 3D lithium anode effectively suppresses lithium dendrites. The assembled batteries deliver a high cycling performance, demonstrating a promising strategy for ambient‐temperature solid‐state lithium metal batteries.
Lithium ion battery cells operating at high‐voltage typically suffer from severe capacity fading, known as ‘rollover’ failure. Here, the beneficial impact of Li2CO3 as an electrolyte additive for ...state‐of‐the‐art carbonate‐based electrolytes, which significantly improves the cycling performance of NCM523 ∥ graphite full‐cells operated at 4.5 V is elucidated. LIB cells using the electrolyte stored at 20 °C (with or without Li2CO3 additive) suffer from severe capacity decay due to parasitic transition metal (TM) dissolution/deposition and subsequent Li metal dendrite growth on graphite. In contrast, NCM523 ∥ graphite cells using the Li2CO3‐containing electrolyte stored at 40 °C display significantly improved capacity retention. The underlying mechanism is successfully elucidated: The rollover failure is inhibited, as Li2CO3 reacts with LiPF6 at 40 °C to in situ form lithium difluorophosphate, and its decomposition products in turn act as ‘scavenging’ agents for TMs (Ni and Co), thus preventing TM deposition and Li metal formation on graphite.
The high‐voltage operation of NCM || graphite lithium ion cells is a serious challenge and results in severe capacity fading, due to transition metal (Ni, Co, Mn) dissolution from the cathode and deposition at the anode, subsequently inducing Li metal dendrite formation. This failure can be inhibited by suitable electrolyte additives, acting as ‘scavenging’ agents for transition metals.
Lithium‐metal electrodes have undergone a comprehensive renaissance to meet the requirements of high‐energy‐density batteries due to their lowest electrode potential and the very high theoretical ...capacity. Unfortunately, the unstable interface between lithium and nonaqueous electrolyte induces dendritic Li and low Coulombic efficiency during repeated Li plating/stripping, which is one of the huge obstacles toward practical lithium‐metal batteries. Here, a composite mixed ionic/electronic conductor interphase (MCI) is formed on the surface of Li by in situ chemical reactions of a copper‐fluoride‐based solution and Li metal at room temperature. The as‐obtained MCI film acts like the armor of a soldier to protect the Li‐metal anode by its prioritized lithium storage, high ionic conductivity, and high Young's modulus. The armored MCI can effectively suppress Li‐dendrite growth and work effectively in LiNi0.5Co0.2Mn0.3O2/Li cells. The armored MCI presents fresh insights into the formation and regulation of the stable electrode–electrolyte interface and an effective strategy to protect Li‐metal anodes in working Li‐metal batteries.
A composite mixed ionic/electronic conductor interphase (MCI) is formed on the surface of lithium by in situ chemical reactions of copper‐fluoride‐based solution and Li metal at room temperature. The as‐obtained MCI film acts like the armor of a soldier to protect the Li‐metal anode by its prioritized lithium storage, high ionic conductivity, and high Young's modulus.
The serious safety issues caused by uncontrollable lithium (Li) dendrite growth, especially at high current densities, seriously hamper the rapid charging of Li metal‐based batteries. Here, the ...construction of Al–Li alloy/LiCl‐based Li anode (ALA/Li anode) is reported by displacement and alloying reaction between an AlCl3‐ionic liquid and a Li foil. This layer not only has high ion‐conductivity and good electron resistivity but also much improved mechanical strength (776 MPa) as well as good flexibility compared to a common solid electrolyte interphase layer (585 MPa). The high mechanical strength of the Al–Li alloy interlayer effectively eliminates volume expansion and dendrite growth in Li metal batteries, so that the ALA/Li anode achieves superior cycling for 1600 h (2.0 mA cm−2) and 1000 cycles at an ultrahigh current density (20 mA cm−2) without dendrite formation in symmetric batteries. In lithium–sulfur batteries, the dense alloy layer prevents direct contact between polysulfides and Li metal, inhibiting the shuttle effect and electrolyte decomposition. Long cycling performance is achieved even at a high current density (4 C) and a low electrolyte/sulfur (6.0 µL mg−1). This easy fabrication process provides a strategy to realize reliable safety during the rapid charging of Li‐metal batteries.
The universal Al–Li alloy‐based layer is demonstrated to be highly effective for stabilizing the lithium metal anode at an ultrahigh current density. The high strength layer not only inhibits the growth of lithium dendrites but also prevents the parasitic reactions of Li with the liquid electrolyte and polysulfides.
The lifespan of high‐energy‐density lithium metal batteries (LMBs) is hindered by heterogeneous solid electrolyte interphase (SEI). The rational design of electrolytes is strongly considered to ...obtain uniform SEI in working batteries. Herein, a modification of nitrate ion (NO3−) is proposed and validated to improve the homogeneity of the SEI in practical LMBs. NO3− is connected to an ether‐based moiety to form isosorbide dinitrate (ISDN) to break the resonance structure of NO3− and improve the reducibility. The decomposition of non‐resonant −NO3 in ISDN enriches SEI with abundant LiNxOy and induces uniform lithium deposition. Lithium–sulfur batteries with ISDN additives deliver a capacity retention of 83.7 % for 100 cycles compared with rapid decay with LiNO3 after 55 cycles. Moreover, lithium–sulfur pouch cells with ISDN additives provide a specific energy of 319 Wh kg−1 and undergo 20 cycles. This work provides a realistic reference in designing additives to modify the SEI for stabilizing LMBs.
The modification of NO3− is achieved by connecting NO3− to an ether‐based moiety. The broken resonance structure of −NO3 improves its reducibility compared with NO3−. The decomposition of −NO3 forms a LiNxOy‐rich solid electrolyte interphase (SEI) and induces uniform Li deposition.
Due to the technology advancement and the large-scale application of lithium-ion batteries in recent years, the market demand for lithium is growing rapidly and the availability of land lithium ...resources is decreasing significantly. As such, the focus of lithium extraction technologies has shifted to water lithium resources involving salt-lake brines and sea water. Among various aqueous recovery technologies, the lithium ion-sieve (LIS) technology is considered the most promising one. This is because LISs are excellent adsorbents with high lithium uptake capacity, superior lithium selectivity and good cycle performance. These attributes have enabled LISs to separate lithium effectively from aqueous solutions containing different ions. The present work reviews the latest development in LIS technology, including the chemical structures of ion-sieves, the corresponding lithium adsorption/desorption mechanisms, the ion-sieves preparation methods, and the challenges associated with the lithium recovery from aqueous solutions by the LIS batteries. Besides, some common LIS composite materials forming technologies, including granulation, foaming, membrane and fiber formation, and magnetization, which are used to overcome the shortcomings in industrial column operations, are also explored.
Herein, high‐content N‐doped carbon nanotube (CNT) microspheres (HNCMs) are successfully synthesized through simple spray drying and one‐step pyrolysis. HNCM possesses a hierarchically porous ...architecture and high‐content N‐doping. In particular, HNCM800 (HNCM pyrolyzed at 800 °C) shows high nitrogen content of 12.43 at%. The porous structure derived from well‐interconnected CNTs not only offers a highly conductive network and blocks diffusion of soluble lithium polysulfides (LiPSs) in physical adsorption, but also allows sufficient sulfur infiltration. The incorporation of N‐rich CNTs provides strong chemical immobilization for LiPSs. As a sulfur host for lithium–sulfur batteries, good rate capability and high cycling stability is achieved for HNCM/S cathodes. Particularly, the HNCM800/S cathode delivers a high capacity of 804 mA h g−1 at 0.5 C after 1000 cycles corresponding to low fading rate (FR) of only 0.011% per cycle. Remarkably, the cathode with high sulfur loading of 6 mg cm−2 still maintains high cyclic stability (capacity of 555 mA h g−1 after 1000 cycles, FR 0.038%). Additionally, CNT/Co3O4 microspheres are obtained by the oxidation of CNTs/Co in the air. The as‐prepared CNT/Co3O4 microspheres are employed as an anode for lithium‐ion batteries and present excellent cycling performance.
High‐content N‐doped carbon nanotube (CNT) microspheres (HNCMs) can be synthesized by simple spray drying and one‐step pyrolysis. HNCM possesses a hierarchically porous architecture and high‐content N‐doping. The porous structure originating from well‐interconnected N‐CNTs provides a highly conductive network. High‐content N‐doping offers strong chemical immobilization for polysulfides. These merits make HNCM an ideal host material for high‐performance Li–S battery.
In carbonate electrolytes, the organic–inorganic solid electrolyte interphase (SEI) formed on the Li‐metal anode surface is strongly bonded to Li and experiences the same volume change as Li, thus it ...undergoes continuous cracking/reformation during plating/stripping cycles. Here, an inorganic‐rich SEI is designed on a Li‐metal surface to reduce its bonding energy with Li metal by dissolving 4m concentrated LiNO3 in dimethyl sulfoxide (DMSO) as an additive for a fluoroethylene‐carbonate (FEC)‐based electrolyte. Due to the aggregate structure of NO3− ions and their participation in the primary Li+ solvation sheath, abundant Li2O, Li3N, and LiNxOy grains are formed in the resulting SEI, in addition to the uniform LiF distribution from the reduction of PF6− ions. The weak bonding of the SEI (high interface energy) to Li can effectively promote Li diffusion along the SEI/Li interface and prevent Li dendrite penetration into the SEI. As a result, our designed carbonate electrolyte enables a Li anode to achieve a high Li plating/stripping Coulombic efficiency of 99.55 % (1 mA cm−2, 1.0 mAh cm−2) and the electrolyte also enables a Li||LiNi0.8Co0.1Mn0.1O2 (NMC811) full cell (2.5 mAh cm−2) to retain 75 % of its initial capacity after 200 cycles with an outstanding CE of 99.83 %.
An inorganic‐rich solid electrolyte interphase (SEI) has been constructed on Li metal to promote dense Li growth with a Coulombic efficiency of 99.55 % in the carbonate electrolyte. It was synthesized on the surface of the Li‐metal anode using concentrated LiNO3 in dimethyl sulfoxide (DMSO) as an additive in the FEC‐based electrolyte, which participates in the primary Li+ solvation shell and promotes the reduction of NO3− ions to form the inorganic‐rich SEI.
The structures and components of solid electrolyte interphase (SEI) are extremely important to influence the performance of full cells, which is determined by the formulation of electrolyte used. ...However, it is still challenging to control the formation of high‐quality SEI from structures to components. Herein, we designed bisfluoroacetamide (BFA) as the electrolyte additive for the construction of a gradient solid electrolyte interphase (SEI) structure that consists of a lithophilic surface with C−F bonds to uniformly capture Li ions and a LiF‐rich bottom layer to guide the rapid transportation of Li ions, endowing the homogeneous deposition of Li ions. Moreover, the BFA molecule changes the Li+ solvation structure by reducing free solvents in electrolyte to improve the antioxidant properties of electrolyte and prevent the extensive degradation of electrolyte on the cathode surface, which can make a superior cathode electrolyte interphase (CEI) with high‐content LiF.
A gradient SEI structure with C−F rich surface for strong Li+ adsorption and LiF rich bottom for fast Li+ diffusion is designed by applying bisfluoroacetamide as electrolyte additive, which also helps to form a stable CEI on cathode, endowing stable lithium metal batteries.
Lithium–sulfur (Li–S) batteries are regarded as the promising next‐generation energy storage device due to the high theoretical energy density and low cost. However, the practical application of Li–S ...batteries is still limited owing to the cycle stability of both the sulfur cathode and lithium anode. In particular, the instability in the bulk and at the surface of the lithium anode during cycling becomes a huge obstacle for the practical application of Li–S battery. Herein, a Li‐rich lithium–magnesium (Li–Mg) alloy is investigated as an anode for Li–S batteries, based on the consideration of improving the stability in the bulk and at the surface of the lithium anode. Our experimental results reveal that the robust passivation layer is formed on the surface of the Li–Mg alloy anode, which is helpful to reduce side reactions, and enable the smooth surface morphology of anode during cycling. Meanwhile, the mixed electron and Li‐ion conducting matrix of the Li‐poor Li–Mg alloy as a porous skeleton structure can also be formed after delithiation, which can guarantee the structural integrity of the anode in the bulk during Li stripping/plating process. Therefore, the Li‐rich Li–Mg alloy is demonstrated to be a very promising anode material for Li–S battery.
A Li‐rich Li–Mg alloy is investigated as an anode for Li–S batteries. The Li–Mg alloy demonstrates versatile functions, including active material, surface stabilizer, supporting, and conducting matrix, which are beneficial to realize good stability in the bulk and at the surface of the alloy anode for Li–S batteries.
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