With the significant progress that has been made toward the development of cathode materials and electrolytes in lithium‐sulfur (Li‐S) batteries in recent years, the stability of the anode in Li‐S ...batteries has become one of the more urgent challenges in order to reach long‐term stability of Li‐S batteries. In Li‐S batteries, a passivation layer is easily formed on the metallic Li anode surface because of the presence of polysulfides and electrolyte additives. Although the passivation layer on the Li metal anode can significantly suppress Li dendrite growth and improve the safety of Li‐S batteries, continuous corrosion of the Li metal anode eventually leads to battery failure due to the increased cell impedance and the depletion of electrolyte. Here, the recent developments on the protection of the Li metal anode in Li‐S batteries are reviewed. Various strategies used to minimize the corrosion of Li anodes and to reduce its impedance increase are analyzed. Other alternative anodes used in sulfur‐based rechargeable batteries are also discussed.
Recent developments on the anodes of lithium‐sulfur batteries are reviewed. Various strategies used to enhance the cycling stability of anodes are analyzed, with a particular focus on how to minimize the corrosion of lithium anodes and suppressing lithium dendrite growth in the presence of polysulfides. Alternative anodes for sulfur‐based rechargeable batteries are also discussed.
High energy density, nickel (Ni)-rich, layered LiNixMnyCozO2 (NMC, x ≥ 0.6) materials are promising cathodes for lithium-ion batteries. However, several technical challenges, such as fast capacity ...fading and high voltage instability, hinder their large-scale application. Herein, we identified an optimum calcining temperature range for the Ni-rich cathode LiNi0.76Mn0.14Co0.10O2 (NMC76). NMC76 calcined at 750–775 °C exhibits a high discharge capacity (~215 mAh g−1 when charged to 4.5 V) and retains ca. 79% of its initial capacity after 200 cycles. It also exhibits an excellent high-rate capability, delivering a capacity of more than 160 mAh g−1 even at a 10 C rate. The high performance of NMC76 is directly related to the optimized size of its primary particles (100–300 nm) (which constitute the spherical secondary particles of >10 µm) and cation mixing. Higher calcination temperature (≥800 °C) leads to rapid increase of primary particle size, poor cycling stability, and inferior rate capability of NMC76 due to severe micro-strain and -crack formation upon repeated lithium-ion de/intercalations. Therefore, NMC76 calcined at 750–775 °C is a very good candidate for the next generation of Li ion batteries.
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•Temperatures of 750–775 °C are optimum for calcining Ni-rich LiNi0.76Mn0.14Co0.10O2.•The primary particle size of Ni-rich cathodes was controlled by the calcination temperature.•The size of primary particles showed significant effects on the structural integrity of secondary particles.•Ni-rich materials constructed with primary particles of 100–300 nm exhibited the best electrochemical performance.
Anode-Free Rechargeable Lithium Metal Batteries Qian, Jiangfeng; Adams, Brian D.; Zheng, Jianming ...
Advanced functional materials,
October 18, 2016, Letnik:
26, Številka:
39
Journal Article
Recenzirano
Anode‐free rechargeable lithium (Li) batteries (AFLBs) are phenomenal energy storage systems due to their significantly increased energy density and reduced cost relative to Li‐ion batteries, as well ...as ease of assembly because of the absence of an active (reactive) anode material. However, significant challenges, including Li dendrite growth and low cycling Coulombic efficiency (CE), have prevented their practical implementation. Here, an anode‐free rechargeable lithium battery based on a Cu||LiFePO4 cell structure with an extremely high CE (>99.8%) is reported for the first time. This results from the utilization of both an exceptionally stable electrolyte and optimized charge/discharge protocols, which minimize the corrosion of the in situly formed Li metal anode.
Anode‐free rechargeable lithium (Li) batteries (AFLBs) are phenomenal energy storage systems due to their significantly increased energy density and reduced cost relative to Li‐ion batteries, as well as ease of assembly because of the absence of an active (reactive) anode material. An extremely high Coulombic efficiency (>99.8%) of the AFLB is demonstrated.
High-energy nickel (Ni)-rich cathode will play a key role in advanced lithium (Li)-ion batteries, but it suffers from moisture sensitivity, side reactions, and gas generation. Single-crystalline ...Ni-rich cathode has a great potential to address the challenges present in its polycrystalline counterpart by reducing phase boundaries and materials surfaces. However, synthesis of high-performance single-crystalline Ni-rich cathode is very challenging, notwithstanding a fundamental linkage between overpotential, microstructure, and electrochemical behaviors in single-crystalline Ni-rich cathodes. We observe reversible planar gliding and microcracking along the (003) plane in a single-crystalline Ni-rich cathode. The reversible formation of microstructure defects is correlated with the localized stresses induced by a concentration gradient of Li atoms in the lattice, providing clues to mitigate particle fracture from synthesis modifications.
The instability of lithium (Li) metal anodes due to dendritic growth and low Coulombic efficiency (CE) hinders the practical application of high‐energy‐density Li metal batteries. Here, the ...systematic studies of improving the stability of Li metal anodes and the electrochemical performance of Li metal batteries through the addition of combinational additives and the optimization of solvent compositions in dual‐salt/carbonate electrolytes are reported. A dendrite‐free and high CE of 98.1% for Li metal anode is achieved. The well‐protected Li metal anode and the excellent cyclability and rate capability of the 4‐V Li metal batteries are obtained. This is attributed to the formation of a robust, denser, more polymeric, and higher ionic conductive surface film on the Li metal anode via the electrochemical reductive decompositions of the electrolyte components and the ring‐opening polymerization of additives and cyclic carbonate solvents. The key findings of this work indicate that the optimization of solvent compositions and the manipulation of additives are facile and effective ways to enhance the performances of Li metal batteries.
Dendrite‐free and high Coulombic efficiency of 98.1% for Li metal anode are achieved via a facile approach of optimizing solvent compositions and adding combinational additives in LiTFSI‐LiBOB/carbonate electrolytes. The excellent cyclability and rate capability of 4‐V Li metal batteries are attributed to the formation of a robust, denser, more polymeric, and higher ionic conductive surface film on the Li metal anode.
LiNixMnyCo1−x−yO2 (NMC) cathode materials with Ni ≥ 0.8 have attracted great interest for high energy‐density lithium‐ion batteries (LIBs) but their practical applications under high charge voltages ...(e.g., 4.4 V and above) still face significant challenges due to severe capacity fading by the unstable cathode/electrolyte interface. Here, an advanced electrolyte is developed that has a high oxidation potential over 4.9 V and enables NMC811‐based LIBs to achieve excellent cycling stability in 2.5–4.4 V at room temperature and 60 °C, good rate capabilities under fast charging and discharging up to 3C rate (1C = 2.8 mA cm−2), and superior low‐temperature discharge performance down to −30 °C with a capacity retention of 85.6% at C/5 rate. It is also demonstrated that the electrode/electrolyte interfaces, not the electrolyte conductivity and viscosity, govern the LIB performance. This work sheds light on a very promising strategy to develop new electrolytes for fast‐charging high‐energy LIBs in a wide‐temperature range.
Advanced localized high‐concentration electrolytes are developed to inhibit Ni dissolution and particle cracking in high‐Ni (≥0.8) LiNixMnyCo1−x−yO2 cathode materials when cycling under 4.4 V through formation of uniform, robust, and conductive electrode/electrolyte interfaces, thus enabling excellent long‐term cycling stability in a wide‐temperature range, superior fast‐charging and fast‐discharging capabilities, and superior low‐temperture performance when compared to conventional electrolytes.
Porous structured silicon has been regarded as a promising candidate to overcome pulverization of silicon-based anodes. However, poor mechanical strength of these porous particles has limited their ...volumetric energy density towards practical applications. Here we design and synthesize hierarchical carbon-nanotube@silicon@carbon microspheres with both high porosity and extraordinary mechanical strength (>200 MPa) and a low apparent particle expansion of ~40% upon full lithiation. The composite electrodes of carbon-nanotube@silicon@carbon-graphite with a practical loading (3 mAh cm
) deliver ~750 mAh g
specific capacity, <20% initial swelling at 100% state-of-charge, and ~92% capacity retention over 500 cycles. Calendered electrodes achieve ~980 mAh cm
volumetric capacity density and <50% end-of-life swell after 120 cycles. Full cells with LiNi
Mn
Co
O
cathodes demonstrate >92% capacity retention over 500 cycles. This work is a leap in silicon anode development and provides insights into the design of electrode materials for other batteries.
The lithium (Li) metal battery (LMB) is one of the most promising candidates for next‐generation energy storage systems. However, it is still a significant challenge to operate LMBs with high voltage ...cathodes under high rate conditions. In this work, an LMB using a nickel‐rich layered cathode of LiNi0.76Mn0.14Co0.10O2 (NMC76) and an optimized electrolyte 0.6 m lithium bis(trifluoromethanesulfonyl)imide + 0.4 m lithium bis(oxalato)borate + 0.05 m LiPF6 dissolved in ethylene carbonate and ethyl methyl carbonate (4:6 by weight) demonstrates excellent stability at a high charge cutoff voltage of 4.5 V. Remarkably, these Li||NMC76 cells can deliver a high discharge capacity of >220 mA h g−1 (846 W h kg−1) and retain more than 80% capacity after 1000 cycles at high charge/discharge current rates of 2C/2C (1C = 200 mA g−1). This excellent electrochemical performance can be attributed to the greatly enhanced structural/interfacial stability of both the Ni‐rich NMC76 cathode material and the Li metal anode using the optimized electrolyte.
Excellent rate capability and cycling performance in a high voltage lithium (Li) metal battery (LMB) composed of Ni‐rich layered LiNi0.76Mn0.14Co0.10O2 (NMC76) and Li metal are enabled by the formation of stable electrode/electrolyte interfaces in an optimized dual‐salt electrolyte with additive. The Li||NMC76 cell demonstrates a capacity retention above 80% after 1000 cycles at 400 mA g−1 between 2.7–4.5 V.
High‐energy‐density batteries with a LiCoO2 (LCO) cathode are of significant importance to the energy‐storage market, especially for portable electronics. However, their development is greatly ...limited by the inferior performance under high voltages and challenging temperatures. Here, highly stable lithium (Li) metal batteries with LCO cathode, through the design of in situ formed, stable electrode/electrolyte interphases on both the Li anode and the LCO cathode, with an advanced electrolyte, are reported. The LCO cathode can deliver a high specific capacity of ≈190 mAh g−1 and show greatly improved cell performances under a high charge voltage of 4.5 V (even up to 4.55 V) and a wide temperature range from −30 to 55 °C. This work points out a promising approach for developing Li||LCO batteries for practical applications. This approach can also be used to improve the high‐voltage performance of other batteries in a broad temperature range.
High‐voltage LiCoO2 cathodes are highly desirable for various energy‐storage applications, especially when coupled with lithium metal anodes. Fluorine‐rich electrode/electrolyte interphases in situ formed in an advanced ether electrolyte are found to enable highly stable cell cycling under elevated temperatures. Such interphases effectively suppress electrolyte side reactions and preserve the integrity of both cathode and anode materials.
To enable next‐generation high‐power, high‐energy‐density lithium (Li) metal batteries (LMBs), an electrolyte possessing both high Li Coulombic efficiency (CE) at a high rate and good anodic ...stability on cathodes is critical. Acetonitrile (AN) is a well‐known organic solvent for high anodic stability and high ionic conductivity, yet its application in LMBs is limited due to its poor compatibility with Li metal anodes even at high salt concentration conditions. Here, a highly concentrated AN‐based electrolyte is developed with a vinylene carbonate (VC) additive to suppress Li+ depletion at high current densities. Addition of VC to the AN‐based electrolyte leads to the formation of a polycarbonate‐based solid electrolyte interphase, which minimizes Li corrosion and leads to a very high Li CE of up to 99.2% at a current density of 0.2 mA cm‐2. Using such an electrolyte, fast charging of Li||NMC333 cells is realized at a high current density of 3.6 mA cm‐2, and stable cycling of Li||NMC622 cells with a high cathode loading of 4 mAh cm‐2 is also demonstrated.
A highly concentrated acetonitrile‐based electrolyte with a vinylene carbonate additive is developed to significantly suppress Li+ depletion and side reactions on Li metal anode (LMA) at high current densities. High‐power Li metal batteries can be obtained using this electrolyte with a much stabilized LMA and accelerated ion transfer.
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