All‐solid‐state batteries are promising candidates for the next‐generation safer batteries. However, a number of obstacles have limited the practical application of all‐solid‐state Li batteries (ASSLBs), such as moderate ionic conductivity at room temperature. Here, unlike most of the previous approaches, superior performances of ASSLBs are achieved by greatly reducing the thickness of the solid‐state electrolyte (SSE), where ionic conductivity is no longer a limiting factor. The ultrathin SSE (7.5 µm) is developed by integrating the low‐cost polyethylene separator with polyethylene oxide (PEO)/Li‐salt (PPL). The ultrathin PPL shortens Li+ diffusion time and distance within the electrolyte, and provides sufficient Li+ conductance for batteries to operate at room temperature. The robust yet flexible polyethylene offers mechanical support for the soft PEO/Li‐salt, effectively preventing short‐circuits even under mechanical deformation. Various ASSLBs with PPL electrolyte show superior electrochemical performance. An initial capacity of 135 mAh g−1 at room temperature and the high‐rate capacity up to 10 C at 60 °C can be achieved in LiFePO4/PPL/Li batteries. The high‐energy‐density sulfur cathode and MoS2 anode employing PPL electrolyte also realize remarkable performance. Moreover, the ASSLB can be assembled by a facile process, which can be easily scaled up to mass production.
Polymer electrolytes with high ionic conductivity, good interfacial stability and safety are in urgent demand for practical rechargeable lithium metal batteries (LMBs). Herein we propose a novel flame-retardant polymerized 1,...
Among all the possible anode materials for next-generation rechargeable batteries, lithium (Li) metal stands out from the crowd for its high specific capacity and low redox potential. Unfortunately, the issues caused by Li dendrites limit the commercialization of the batteries based on Li metal anodes. Research in recent years has proved that the Li dendrites cannot be completely eliminated. Inspired by the Chinese legend, "King Yu Tamed the Flood," the new strategy of combing dredge and block, to control the diversion of Li ions is proposed. Via Au modification on one side of the carbon fibers matrix (CFs@Au), selective deposition of Li ions on the back side of the current collector is successfully achieved. This is distant from the separator, and hence improves the safety effectively. As a result, the Coulombic efficiency of the CFs@Au-Li anode remains 99.2% throughout 400 cycles. What is more, the Li-S full cell paired with the composite anode also exhibits outstanding performance, even with limited Li. This backside-deposition strategy provides new insight into safe Li metal anode design for high energy density battery systems such as Li-S and Li-O 2 .
Solid–solid reactions are very effective for solving the main challenges of lithium–sulfur (Li–S) batteries, such as the shuttle effect of polysulfides and the high dependence of electrolyte consumption. However, the low sulfur content and sluggish redox kinetics of such cathodes dramatically limit the practical energy density of Li–S batteries. Here a rationally designed hierarchical cathode to simultaneously solve above‐mentioned challenges is reported. With nanoscale sulfur as the core, selenium‐doped sulfurized polyacrylonitrile (PAN/S7Se) as the shell and micron‐scale secondary particle morphology, the proposed cathode realizes excellent solid–solid reaction kinetics in a commercial carbonate electrolyte under high active species loading and a relatively low electrolyte/sulfur ratio. Such an approach provides a promising solution toward practical lithium sulfur batteries.
Using a solid‐state electrolyte (SSE) to stabilize the Li metal anode is widely considered a promising route to develop next‐generation high energy density lithium batteries. Here, a new polycrystalline aluminate‐based SSE (named Li–Al–O SSE) with good capability is introduced to protect Li metal. The SSE is formed on the Li metal surface via a chemical reaction between LiOH and triethylaluminum (TEAL) with the existence of LiTFSI‐based electrolyte. It is a continuous film that consists of polycrystalline LiAlO2, Li3AlO3, Al2O3, Li2CO3, LiF, and some organic compounds. Such Li–Al–O SSE possesses a room‐temperature ionic conductivity as high as 1.42 × 10−4 S cm−1. Meanwhile, it effectively protects the Li anode from the corrosion of H2O, O2, and organic solvent, and suppresses the growth of Li dendrite. With the protection of the Li–Al–O SSE, the cycle life of Li|Li symmetric cell and Li|O2 cell is substantially elongated, indicating that the SSE exhibits an excellent protective effect under both inert and oxidizing circumstances.
Room‐temperature sodium–sulfur (RT−Na/S) batteries hold great promise to meet the requirements of large‐scale energy storage due to their high theoretical energy density, low material cost, resource abundance, and environmental benignity. However, the poor cycle performance and low utilization of active sulfur greatly hinder their practical application. As the essential part directly related to the battery performance, the S‐based cathode has attracted tremendous research interests in recent years. This review highlights recent progress in cathode materials for RT−Na/S batteries. Particularly, basic insights into the Na/S reaction mechanism are presented and representative works on S‐based cathode materials are systematically summarized. The remaining challenges and developing trends of RT−Na/S batteries are also discussed. We hope this review can shed light on the field of next‐generation metal‐sulfur batteries.
Iron hexacyanoferrate (FeHCF) is a promising cathode material for sodium-ion batteries. However, FeHCF always suffers from a poor cycling stability, which is closely related to the abundant vacancy defects in its framework. Herein, post-synthetic and in-situ vacancy repairing strategies are proposed for the synthesis of high-quality FeHCF in a highly concentrated Na4Fe(CN)6 solution. Both the post-synthetic and in-situ vacancy repaired FeHCF products (FeHCF-P and FeHCF-I) show the significant decrease in the number of vacancy defects and the reinforced structure, which can suppress the side reactions and activate the capacity from low-spin Fe in FeHCF. In particular, FeHCF-P delivers a reversible discharge capacity of 131 mAh g−1 at 1 C and remains 109 mAh g−1 after 500 cycles, with a capacity retention of 83%. FeHCF-I can deliver a high discharge capacity of 158.5 mAh g−1 at 1 C. Even at 10 C, the FeHCF-I electrode still maintains a discharge specific capacity of 103 mAh g−1 and retains 75% after 800 cycles. This work provides a new vacancy repairing strategy for the solution synthesis of high-quality FeHCF.
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