Noticeable pseudo‐capacitance behavior out of charge storage mechanism (CSM) has attracted intensive studies because it can provide both high energy density and large output power. Although cyclic voltammetry is recognized as the feasible electrochemical technique to determine it quantitatively in the previous works, the results are inferior due to uncertainty in the definitions and application conditions. Herein, three successive treatments, including de‐polarization, de‐residual and de‐background, as well as a non‐linear fitting algorithm are employed for the first time to calibrate the different CSM contribution of three typical cathode materials, LiFePO4, LiMn2O4 and Na4Fe3(PO4)2P2O7, and achieve well‐separated physical capacitance, pseudo‐capacitance and diffusive contributions to the total capacity. This work can eliminate misunderstanding concepts and correct ambiguous results of the pseudo‐capacitance contribution and recognize the essence of CSM in electrode materials.

The increasing demands for renewable energy to substitute traditional fossil fuels and related large‐scale energy storage systems (EES) drive developments in battery technology and applications today. The lithium‐ion battery (LIB), the trendsetter of rechargeable batteries, has dominated the market for portable electronics and electric vehicles and is seeking a participant opportunity in the grid‐scale battery market. However, there has been a growing concern regarding the cost and resource availability of lithium. The sodium‐ion battery (SIB) is regarded as an ideal battery choice for grid‐scale EES owing to its similar electrochemistry to the LIB and the crust abundance of Na resources. Because of the participation in frequency regulation, high pulse‐power capability is essential for the implanted SIBs in EES. Herein, a comprehensive overview of the recent advances in the exploration of high‐power cathode and anode materials for SIB is presented, and deep understanding of the inherent host structure, sodium storage mechanism, Na+ diffusion kinetics, together with promising strategies to promote the rate performance is provided. This work may shed light on the classification and screening of alternative high rate electrode materials and provide guidance for the design and application of high power SIBs in the future.

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Single‐crystalline cathode materials have attracted intensive interest in offering greater capacity retention than their polycrystalline counterparts by reducing material surfaces and phase boundaries. However, the single‐crystalline LiCoO2 suffers severe structural instability and capacity fading when charged to high voltages (4.6 V) due to Co element dissolution and O loss, crack formation, and subsequent electrolyte penetration. Herein, by forming a robust cathode electrolyte interphase (CEI) in an all‐fluorinated electrolyte, reversible planar gliding along the (003) plane in a single‐crystalline LiCoO2 cathode is protected due to the prevention of element dissolution and electrolyte penetration. The robust CEI effectively controls the performance fading issue of the single‐crystalline cathode at a high operating voltage of 4.6 V, providing new insights for improved electrolyte design of high‐energy‐density battery cathode materials.