Hierarchical V2O5 microspheres composed of stacked platelets are fabricated through a facile, low-cost, and energy-saving approach. The preparation procedure involves a room-temperature precipitation of precursor microspheres in aqueous solution and subsequent calcination. Because of this unique structure, V2O5 microspheres manifest a high capacity (266 mA h g(-1)), excellent rate capability (223 mA h g(-1) at a current density 2400 mA g(-1)), and good cycling stability (200 mA h g(-1) after 100 cycles) as cathode materials for lithium-ion batteries.

The main bottlenecks restricting the development of Na-ion batteries are the inferior rate capability and cyclability of cathodes. In this work, a novel cathode material for Na-ion storage, namely, low crystallinity VOOH hollow microspheres, is prepared through a template-free hydrothermal route, and exhibits outstanding rate behavior and long life.

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N-Methylacetamide(NMA) is used as an electrolyte component to suppress co-intercalation of propylene carbonate (PC) molecules into graphite anode in lithium ion batteries. From the cyclic voltammetric and charge-discharge properties of graphite in PC-based electrolyte containing NMA component, it is found that the addition of NMA solvent is effective in suppressing co-intercalation and irreversible decomposition of PC solvent. Graphite anode can be effectively cycled in the electrolyte and the first coulombic efficiency of 75.9% is obtained. SEM and EDX studies show that NMA participates in the formation of solid electrolyte interphase (SEI), which is able to inhibit co-intercalation and irreversible reductive decomposition of PC molecules. Raman spectroscopic investigation reveals that the interaction between Li ion and PC is decreased because Li ion can be preferentially solvated by solvent NMA. When NMA is used as an additive in PCethylene carbonate (EC) co-solvent electrolyte, the first coulombic efficiency is obtained to be 87.6%, considerably higher than that of 51.6% obtained in the reference electrolyte. The cycling stability of graphite electrode is also significantly improved in the NMA-added electrolyte.

Electrolytes play an essential role in determining the safety and electrochemical performance of Li-ion batteries. This work reported a propylene carbonate-based electrolyte with high-concentration Li salt. The fire-retardancy test and thermogravimetric analysis showed that this electrolyte is of high safety. In addition, this electrolyte exhibited superior electrochemical performance as compared with the commercial electrolyte in case of reversible capacity, rate behavior, and cycling stability.