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Abstract: We report here the spherical Na2Ti3O7 synthesized by spray drying of the sol-gel prepared precursor suspension and followed by a solid-state calcination as advanced anode material for sodium-ion battery. Field-emission scanning electron microscopy analyses show the spherical powders consisting of well-crystallized Na2Ti3O7 primary particles surrounded three-dimensional porous structure. Electrochemical performance was investigated by charge/discharge measurement exhibiting the charge capacity of 93.1mAh g−1 even at current rate of 5C after 50th cycle. The electrochemical performance at high current rate is better than that of by a solid-state reaction method. Na2Ti3O7 synthesized by combing spraying-dry and sol-gel method is one of the promising candidates as the anode material of sodium-ion battery. [Copyright &y& Elsevier]

Lithium (Li) metal has been regarded as one of the most promising anodes for the next-generation high-energy-density batteries. However, the large volumetric variation and uncontrollable Li dendrite growth have delayed the large-scale application. For the sake of ultrahigh theoretical capacity, low alloying potential, and small dimensional expansion, Li-Al alloy has come into sight as an appealing candidate for Li anode. Herein, as-prepared Li-rich dual-phase Li-Al alloys with abundant Li and Li 9 Al 4 three-dimensional (3D) framework are fabricated via a one-step melting approach. Different from typical facial modification of Li anode, our Li-Al alloy can improve the electrochemical behavior of anode, fundamentally from surface and matrix prospect. Owing to the favorable lithiophilicity, increased specific surface, and regulated Li ion (Li+) flux, Li-Al symmetric cell presents excellent cyclic reversibility and stability (more than 1400 h, and smaller voltage hysteresis of 76 mV at 300th cycle), at the current density of 1 mA cm 2 and areal capacity of 1 mAh cm 2. Furthermore, Li-Al alloy anode is paired with LiFePO 4 cathode to assemble full battery, which enables 250 cycles at 1.0 C with a high-capacity retention rate of 94.7 %. This contribution offers new insights into the feasible preparation of Li-Al alloy composite and in-depth understanding of working mechanism toward dendrite-free and minimum-volume-change Li anode. [Display omitted] • Designing a conductive, affinitive and stable framework for Li anode protection from the surface and bulk perspective. • Inducing uniform deposition and minimum dimensional change to enable dendrite-free Li anode. • Realizing impressive mass capacity and cyclic stability in full-cells. [ABSTRACT FROM AUTHOR]

Li metal is considered as the preferred anode material to replace graphite in next generation of Li metal battery. However, the shortages including Li dendrite growth are hindering its practical application. In addition, Li metal is unstable in ambient air, which brings safety risk for assembling and operating of Li metal battery. Herein, we deposit Al thin film on Li foil as the protective layer by magnetron sputtering. The Al-coated Li metal electrode shows higher stability in the air and carbonate-based electrolyte. Moreover, the Li electrode with Al coating layer exhibits metallic luster even after 200 cycles, and the cycling lifetime is expanded over 950 h at 0.5 mA cm−2 and 0.5 mAh cm−2. The improved electrochemical performance is attributed to the formation of a stable Li-Al alloy layer on the electrode surface, where the reduced Li atoms can diffuse into the alloy layer resulting in the formation of dense and compact Li metal anode. [ABSTRACT FROM AUTHOR]

Lithium metal is an ideal anode material for lithium battery thanks to its ultra-high specific capacity and lowest redox potential. However, uncontrollable growth of lithium dendrites hinders its application due to local aggregation of lithium ions and anisotropic growth of lithium metal driven by uneven electric field distribution. Here a strategy is proposed to address this issue via utilizing porous equipotential body decorated with heterogeneous nucleation sites as advanced three-dimensional current collector. The conductive network of carbon nanofibers is recognized as a porous equipotential body, where the interior electric filed is zero due to the well-defined electric field shielding effect. In addition, copper nanoparticles as heterogeneous nucleation sites are uniformly anchored on carbon nanofibers, which guide lithium deposition evenly. As a result, lower impedance and higher Coulombic efficiency (∼97%) are achieved in modified lithium-copper cell. In particular, the cycling lifetime of modified symmetric lithium-lithium cell is expanded up to 500 cycles at extremely large current density of 50 mA cm−2. [ABSTRACT FROM AUTHOR]

• PAN nanofibers enhance mechanical performance of PEO-succinonitrile electrolyte. • Composite electrolyte shows enhanced electrochemical performance. • Li-Sn alloy layer coted on Li anode can offer a passivated surface. • Electrolyte/anode interface is optimized by the synergistic effect. • Room-temperature solid-state battery can cycle 2400 h in symmetric configuration. Poly(ethylene oxide) polymer electrolyte composited with high content of succinonitrile organic plasticizer has excellent ionic conductivity at room temperature. Unfortunately, the poor interface stability between this novel solid polymer electrolyte (SPE) and Li metal anode leads to limited cycling performance, which seriously hinders its commercial applications. Herein, the electrospun nanofibers framework of polyacrynitrile (PAN) is introduced as a three-dimensional polymer filler, which can not only provide a robust skeleton for improved mechanical stability, but also inhibit the growth of Li dendrites with increased Li ion transference number from 0.28 to 0.41. Meanwhile, the Li anode is modified via constructing a dense Li-Sn alloy layer, offering a perfectly passivated anode surface and eliminating the side reaction between metallic Li and SPE efficiently. Hence, the interface compatibility and structure stability between the anode and the polymer electrolyte are greatly improved in the prolongated cyclic testing due to the synergistic effect of PAN reinforced SPE and Li-Sn alloy layer coated Li. As a result, the symmetrical battery can cycle stably for 2400 h at 25 °C under 0.1 mA cm−2 and 0.1 mAh cm−2, while the LiFePO 4 based full battery can keep a good capacity retention of 85 % even after 500 cycles at 0.5 C. This work demonstrates that the combination of modifying SPE and building advanced interface layer on the Li anode is an effective measure to optimize the room temperature cycling performance of polymer solid-state Li battery. [ABSTRACT FROM AUTHOR]

• LiF headspace affixed Li composite accommodates Li deposition perfectly. • LiF array as the framework on the surface provides fast Li+ diffusion paths. • The LZLF anode renders a prolongated cyclic lifetime. Lithium (Li) metal composite with three-dimensional (3D) skeleton is regarded as the promising anode material for next generation rechargeable high energy batteries. Currently, most of the commercial cathodes are compounds rich of Li elements. In the initial operation of the as-assembled full cell, Li atoms are released from the cathode and directly deposited on the anode surface. The absence of the storage space in the conventional Li composite anode makes Li growth in an uncontrolled way and serious volume fluctuation of the electrode. Herein, LiF headspace affixed Li composite anode is prepared for the first time via a facile one-step thermal fusion method. The storage space constructed by LiF particles is formed on the top surface of 3D Li-LiZn-LiF (LZLF) composite anode, which can accommodate Li deposition from the cathode maintaining structural stability of the anode. Additionally, the LiF particles array on the surface can benefit for fast Li+ diffusion, suppressing Li dendrites growth and inducing uniform Li deposition. In a consequence, the LiF headspace affixed LZLF composite anode shows significantly improved electrochemical performance, i.e., more than 1000 h in symmetrical cell at 1 mA cm−2 and 1 mAh cm−2, or capacity retention of 88.9% after 800 cycles for the full cell at 1C with 2.45 mAh cm−2 in carbonate ester-based electrolyte. [ABSTRACT FROM AUTHOR]