The O3-type NaNi_1/3Fe_1/3Mn_1/3O₂ (NFM) has emerged as a highly promising cathode material for sodium-ion batteries due to its facile synthesis and high theoretical capacity. However, it suffers from severe capacity and rate capability degradation caused by multiple coupled failure mechanisms, including irreversible phase transitions, structural deterioration at high voltages, and electrolyte-induced surface corrosion. This work addresses the challenge of high-voltage stability in NFM cathodes via a synergistic bulk-phase and interface engineering strategy. Firstly, Li, Ti, and Co are co-doped into the bulk lattice structure to suppress the Mn³⁺-induced Jahn-Teller distortion and improve Na⁺ diffusion kinetics. And then, an AlPO₄ protective coating layer is fabricated to mitigate electrolyte corrosion and interfacial side reactions. Consequently, the as-designed composite cathode (AP@NFMLTC) can effectively suppress the P3 to O3’ phase transition within the voltage range of 2.0 to 4.2 V, resulting in a highly reversible sodium storage mechanism. After 100 cycles at a rate of 1 C, the capacity retention rate significantly improves from 45.6% to 83.6%, with a minimal voltage decay of just 0.08 V. The dual bulk-interface synergistic strategy in this work provides valuable insights into achieving high stable operation for sodium-ion batteries (SIBs) cathodes under enhanced voltage.

Lithium metal batteries are emerging as a strong candidate in the future energy storage market due to its extremely high energy density. However, the uncontrollable lithium dendrites and volume change of lithium metal anodes severely hinder its application. In this work, the porous Cu skeleton modified with Cu₆Sn₅ layer is prepared via dealloying brass foil following a facile electroless process. The porous Cu skeleton with large specific surface area and high electronic conductivity effectively reduces the local current density. The Cu₆Sn₅ can react with lithium during the discharge process to form lithiophilic Li₇Sn₂ in situ to promote Li-ions transport and reduce the nucleation energy barrier of lithium to guide the uniform lithium deposition. Therefore, more than 300 cycles at 1 mA cm⁻² are achieved in the half-cell with an average Coulombic efficiency of 97.5%. The symmetric cell shows a superior cycle life of more than 1000 h at 1 mA cm⁻² with a small average hysteresis voltage of 16 mV. When coupled with LiFePO₄ cathode, the full cell also maintains excellent cycling and rate performance.

Lithium-ion capacitor has structure of consisting of the battery-type anode and capacitor-type cathode, thus having a enabling high energy density and a high power density. This capacitor expected to become the next generation of new energy storage devices. The kinetic mismatch between the Faradaic battery-type anode and capacitive cathode is a great challenge for lithium-ion capacitors. Therefore, researchers have developed a variety of high-rate lithium-ion battery materials. Among these materials, vanadium-based materials are considered as ideal anode materials for lithium-ion capacitor due to their low cost, large specific capacity, and superior rate performance. This review summarized recent work on the optimization strategies of several vanadium-based anode materials, i.e. Li₃VO₄, VN and Li₃V₂O₅. In addition, the future directions in the application of vanadium-based anode materials for lithium-ion capacitor were also proposed.