The electrochemical insertion of Li into graphite initiates a series of thermodynamic and kinetic processes. An in-depth understanding of this phenomenon will deepen the knowledge of electrode material design and optimize rechargeable Li batteries. In this context, the phase transition from dense stage II (LiC) to stage I (LiC) was comprehensively elucidated in a graphite anode via both experimental characterizations and first-principles calculations. The results indicate that, although the transition from stage II to stage I is thermodynamically allowed, the process is kinetically prohibited because Li ions tend to cluster into stage compounds rather than form a solid solution. Additionally, the phase transitions involve at least three intermediate structures (1T, 2H, and 3R) before reaching the LiC (stage I) phase. These findings provide new insights into the electrochemical behavior of graphite and the electrode process kinetics for rechargeable Li batteries.

In this study, a g-C 3 N 4 -Cu 2 O-TiO 2 photocatalyst with a novel three-dimensional ordered macroporous (3DOM) structure was successfully prepared using a sacrificial template strategy and a photodeposition method. The influence of the special porous structure with cross pore channels on the photocatalytic properties of the as-prepared sample was studied in detail. Compared with the original photocatalyst (TiO 2 with 3 wt% Pt), g-C 3 N 4 -Cu 2 O-TiO 2 exhibited a higher specific surface area and more active sites, thus accelerating the separation efficiency of the photogenerated electron-hole pair. Consequently, the as-prepared photocatalyst showed good photocatalytic performance, reaching a maximum hydrogen production rate of 12,108 µmol g −1 h −1 and approximately five times higher than that of the pristine comparison sample. The enhanced photoactivity of the g-C 3 N 4 -Cu 2 O-TiO 2 heterojunction can be ascribed to its double p-n heterojunction and robust porous structure, where the photodeposited Cu 2 O plays a synergistic catalytic role in the photocatalytic process and the outer clad g-C 3 N 4 layer prevents Cu 2 O oxidation. Additionally, the possible photocatalytic mechanism was briefly discussed based on the experimental results. This work identifies viable pathways for developing low-cost heterojunction photocatalysts with highly efficient photocatalytic activity toward improved solar energy conversion.

Hard carbon (HC) is the most likely to be commercialized anode material for sodium-ion batteries (SIBs). However, its low initial Coulombic efficiency (ICE) impeding the further large-scale industrialization. Since the...

Rechargeable Li metal batteries have attracted lots of attention because they can achieve high energy densities. However, the commercialization of rechargeable Li metal batteries is delayed because Li dendrites may be generated during the batteries' electrochemical cycles, which may cause severe safety issues. In this research, a Li-B alloy is investigated as an anode for rechargeable batteries instead of Li metal. Results show that the Li-B alloy has better effects in suppressing the formation of dendritic lithium, reducing the interface impedance and improving the cycle performance. These effects may result from the unique structure of Li-B alloy, in which free lithium is embedded in the Li 7 B 6 framework. These results suggest that Li-B alloy may be a promising anode material applicable in rechargeable lithium batteries.

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