Because of the superiority of low cost and high theoretical capacity, sodium metal batteries are considered an attractive option for high energy storage. However, the uncontrollable and random deposition of Na tends to expedite the formation of Na dendrites and increases the risk of thermal runaway. The method of preplant sodiophilic sites can induce the lateral deposition of Na instead of sharp dendrite emergence. Here, we introduce the sodiophilic V₂O₃ particles to form a protective layer on Na surface (Na/V₂O₃). The high Na ion adsorption energy and low nucleation overpotential of Na/V₂O₃ facilitate the diffusion of Na ions and homogeneous Na deposition, which can work well in cubing dendrite development. Thus, the symmetrical cell (Na/V₂O₃||Na/V₂O₃) can stably operate for 670 h at 0.5 mA·cm⁻²/1 mAh·cm⁻² with a smaller voltage hysteresis (less than 100 mV). Moreover, full cell constructed by coupling Na/V₂O₃ anode with Na₃V₂(PO₄)₃ cathode displays an outstanding rate performance, maintaining a high capacity of 70 mAh·g⁻¹ at 30 C. On the basis of the design of sodiophilic protection layer, a dendrite-free, outstanding rate performance, and long lifespan sodium metal battery is realized.

VS₄ has an one-dimensional chain structure with the chain spacing of 0.583 nm, which is greater than Na⁺ ion radius of 0.102 nm. Moreover, its theoretical sodium storage capacity is 1196 mA·h/g, making it one of the most promising anode materials for sodium storage. However, the volume of the electrode material expands and contracts dramatically during repeated cycling, resulting in collapse of the structure, poor cycling stability and capacity decay, and severely affecting the practical application of VS₄. In this paper, VS₄ microspheres (approximately 1 μm in diameter) with a high stability were constructed for the unique three-dimensional microsphere structure to alleviate the volume expansion, improve the cycling stability and the electrochemical reaction kinetics. This microsphere structured material as an anode material for sodium ion batteries exhibits a superior rate performance (i.e., 372 mA·h/g@2.0 A/g and 297 mA·h/g@5.0 A/g) and a long-cycle life (i.e., stable cycling for 100 times at 5.0 A/g).

Lithium ion batteries (LIBs) that can be operated under extended temperature range hold significant application potentials. Here in this work, we successfully synthesized Co₂V₂O₇ electrode with rich porosity from a facile hydrothermal and combustion process. When applied as anode for LIBs, the electrode displayed excellent stability and rate performance in a wide range of temperatures. Remarkably, a stable capacity of 206 mAh·g^-1 was retained after cycling at a high current density of 10 A·g^-1 for 6,000 cycles at room temperature (25 °C). And even when tested under extreme conditions, i.e., -20 and 60 °C, the battery still maintained its remarkable stability and rate capability. For example, at -20 °C, a capacity of 633 mAh·g^-1 was retained after 50 cycles at 0.1 A·g^-1; and even after cycling at 60 °C at 10 A·g^-1 for 1,000 cycles, a reversible capacity of 885 mAh·g^-1 can be achieved. We believe the development of such electrode material will facilitate progress of the next-generation LIBs with wide operating windows.