A molten lithium infusion strategy has been proposed to prepare stable Li-metal anodes to overcome the serious issues associated with dendrite formation and infinite volume change during cycling of lithium-metal batteries. Stable host materials with superior wettability of molten Li are the prerequisite. Here, it is demonstrated that a series of strong oxidizing metal oxides, including MnO 2 , Co 3 O 4 , and SnO 2 , show superior lithiophilicity due to their high chemical reactivity with Li. Composite lithium-metal anodes fabricated via melt infusion of lithium into graphene foams decorated by these metal oxide nanoflake arrays successfully control the formation and growth of Li dendrites and alleviate volume change during cycling. A resulting Li-Mn/graphene composite anode demonstrates a super-long and stable lifetime for repeated Li plating/stripping of 800 cycles at 1 mA cm −2 without voltage fluctuation, which is eight times longer than the normal lifespan of a bare Li foil under the same conditions. Furthermore, excellent rate capability and cyclability are realized in full-cell batteries with Li-Mn/graphene composite anodes and LiCoO 2 cathodes. These results show a major advancement in developing a stable Li anode for lithium-metal batteries.

Ion gel electrolytes show great potential in solid-state batteries attributed to their outstanding characteristics. However, because of the strong ionic nature of ionic liquids, ion gel electrolytes generally exhibit low lithium-ion transference number, limiting its practical application. Aminefunctionalized boron nitride (BN) nanosheets (AFBNNSs) are used as an additive into ion gel electrolytes for improving their ion transport properties. The AFBNNSs-ion gel shows much improved mechanical strength and thermal stability. The lithium-ion transference number is increased from 0.12 to 0.23 due to AFBNNS addition. More importantly, for the first time, nuclear magnetic resonance analysis reveals that the amine groups on the BN nanosheets have strong interaction with the bis(trifluoromethanesulfonyl)imide anions, which significantly reduces the anion mobility and consequently increases lithium-ion mobility. Battery cells using the optimized AFBNNSs-ion gel electrolyte exhibit stable lithium deposition and excellent electrochemical performance. A LiFePO 4 |Li cell retains 92.2% of its initial specific capacity after the 60th cycle while the cell without AFBNNSs-gel electrolyte only retains 53.5%. The results not only demonstrate a new strategy to improve lithium-ion transference number in ionic liquid electrolytes, but also open up a potential avenue to achieve solid-state lithium metal batteries with improved performance. and high safety levels. Lithium metal batteries (LMBs), owing to the low redox potential (−3.04 V vs standard hydrogen electrode) and ultrahigh theoretical capacity (3860 mAh g −1 ) of the lithium (Li) metal anode, are promising to fulfill these requirements. [1] However, the organic liquid electrolyte (LE), currently widely used in the LMBs, makes LMBs face severe safety concerns such as electrolyte leakage and combustion due to the intrinsic fluidity, flammability, and electrochemical instability. Replacing the organic liquid electrolyte with solid-state electrolytes (SSEs) has been proven to be an efficient way to overcome these problems. [2] Because of their high mechanical stability and structural integrity, SSEs enable facile cell fabrication and prevent electrolyte leakage, offering greater safety than liquid electrolytes. Current solid-state electrolytes include solid polymer electrolytes (SPEs) and inorganic electrolytes (IEs). Unfortunately, SPEs suffer from a poor ionic conductivity at room temperature, while the IEs show innate brittleness and intrinsically narrow electrochemical stability along with high contact resistance. Compared to SPEs and IEs, gel electrolytes, which are prepared by entrapping liquid electrolytes into a solid matrix, provide exceptional properties such as high ionic conductivity, low interfacial resistance, good mechanical strength, and flexibility.Liquid mediums are one of the key components in gel electrolytes. Among the candidates, ionic liquids (ILs), also known as room temperature molten salts, can result in high performance gel electrolytes because of the...

The hybridisation of CoO and FeO nanoparticles dispersed in a super P carbon matrix is proposed as a favourable approach to improve the electrochemical performance (reversible capacity, cycling stability and rate capability) of the metal oxide electrodes in metal-ion batteries. Hybrid CoO-FeO/C is prepared by a simple, cheap and easily scalable molten salt method combined with ball-milling and used in sodium-ion and potassium-ion batteries for the first time. The electrode exhibits excellent cycling stability and superior rate capability in sodium-ion cells with a capacity recovery of 440 mA h g (93% retention) after 180 long-term cycles at 50-1000 mA g and back to 50 mA g. In contrast, CoO-FeO, CoO and FeO electrodes display unsatisfactory electrochemical performance. The hybrid CoO-FeO/C is also reactive with potassium and capable of delivering a reversible capacity of 220 mA h g at 50 mA g which is comparable with the most reported anode materials for potassium-ion batteries. The obtained results broaden the range of transition metal oxide-based hybrids as potential anodes for K-ion and Na-ion batteries, and suggest that further studies of these materials with potassium and sodium are worthwhile.

Controlling mechanochemistry by varying milling conditions.

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