Low Barriers and Faster Electron/Ion Transport Rates through the Ga2O3/MnCO3 Anode with a Heterojunction Structure for Lithium-Ion Batteries.

Electrode stability can be controlled to a large extent by constructing suitable composite structures, in which the heterojunction structure can affect the transport of electrons and ions through the effect of the interface state, changed band gap width, and the electric field at the interface. As a promising electrode material, the Ga-based material has a conversion between solid and liquid phases in the electrochemical reaction process, which endows it with self-healing properties with the structure and morphology. Based on these, the Ga2O3/MnCO3 composite was successfully synthesized with a heterogeneous structure by introducing a Ga source in the hydrothermal process. Benefitting from the acceleration effect of the internal electric field and the narrower band gap at the interface, a high-capacity Ga2O3/MnCO3 composite electrode (1112 mAh·g-1 after 225 cycles at 0.1 A·g-1 and 457.1 mAh·g-1 after 400 cycles at 1 A·g-1) can be achieved for lithium-ion batteries. The results can provide a reference for the research and preparation of electrode materials with high performance.

Ga2O3 Quantum Dots with N-Doped Amorphous Carbon Fixed for Efficient Storage and Transfer of Lithium Ions by Introduction of Dopamine Hydrochloride.

The Ga2O3 anode has great potential due to its self-healing and high theoretical capacity in lithium-ion batteries. Like anodes with other transition metal oxides, the Ga2O3 anode has the problems of structural change and low electrical conductivity. The electrochemical performance of the Ga2O3 anode still needs to be improved. In this work, we synthesized a Ga2O3 quantum dots@N-doped carbon (Ga2O3-QD@NC) composite by hydrothermal reaction with a carbon source of dopamine hydrochloride, in which Ga2O3 quantum dots were dispersed in the interior of the amorphous carbon. Such a special structure is conducive to the high-speed migration of lithium ions and electrons and effectively inhibits volume expansion and agglomeration. Smaller and more uniform quantum dots facilitate efficient repair of the structure. Due to these advantages, the Ga2O3-QD@NC electrode has great electrochemical performance. The Ga2O3-QD@NC electrode has an initial discharge capacity of 1580 mAh g-1 with a high first Coulombic efficiency of 62.8% and a cycling capacity of 953 mAh g-1 under 0.1 A g-1. It even has a capacity of 460 mAh g-1 at 1 A g-1 after 300 cycles. This strategy can provide a new direction for the Ga2O3 anode in lithium-ion batteries with high capacity.