Prelithiation has important applications to convert a nonlithiated cathode or anode materials into a controllably lithiated state required for developing advanced Li-ion batteries. However, most of the prelithiation reagents developed so far are highly reactive and sensitive to oxygen and moisture and therefore difficult for practical battery application. In this work, we developed a facile prelithiation strategy using lithium naphthalenide to fully prelithiate sulfur−poly(acrylonitrile) (S-PAN) composite into a Li 2 S-PAN cathode and to partially prelithiate nanosilicon into a Li x Si anode, which leads to a new version of silicon/sulfur Li-ion battery. This Li x Si/Li 2 S-PAN battery can demonstrate a high specific energy of 710 Wh kg −1 , with a high initial Coulombic efficiency of 93.5% and a considerable cyclability. Also, this chemical prelithiation approach is mild, efficient, and widely applicable to a large range of Li-deficient electrodes, opening up new possibilities for development of low cost, environmentally benign, and high capacity Li-ion batteries.

Hard carbons (HC) have potential high capacities and power capability, prospectively serving as an alternative anode material for Li‐ion batteries (LIB). However, their low initial coulombic efficiency (ICE) and the resulting poor cyclability hinder their practical applications. Herein, a facile and effective approach is developed to prelithiate hard carbons by a spontaneous chemical reaction with lithium naphthalenide (Li‐Naph). Due to the mild reactivity and strong lithiation ability of Li‐Naph, HC anode can be prelithiated rapidly in a few minutes and controllably to a desirable level by tuning the reaction time. The as‐formed prelithiated hard carbon (pHC) has a thinner, denser, and more robust solid electrolyte interface layer consisting of uniformly distributed LiF, thus demonstrating a very high ICE, high power, and stable cyclability. When paired with the current commercial LiCoO2 and LiFePO4 cathodes, the assembled pHC/LiCoO2 and pHC/LiFePO4 full cells exhibit a high ICE of >95.0% and a nearly 100% utilization of electrode‐active materials, confirming a practical application of pHC for a new generation of high capacity and high power LIBs.

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Hard carbon has been regarded as the most promising anode material for sodiumion batteries (SIBs) due to its low cost, high reversible capacity, and low working potential. However, the uncertain sodium storage mechanism hinders the rational design and synthesis of high-performance hard carbon anode materials for practical SIBs. During the past decades, tremendous efforts have been put to stimulate the development of hard carbon materials. In this review, we discuss the recent progress of the study on the sodium storage mechanism of hard carbon anodes, and the effective strategies to improve their sodium storage performance have been summarized. It is anticipated that hard carbon anodes with high electrochemical properties will be inspired and fabricated for large-scale energy storage applications.

Advanced electrolytes play a key role in the development of next-generation lithium secondary batteries. However, many strong polar solvents, as a major component of the electrolyte, are incompatible with the commercialized graphite anode in Li-ion batteries. In this work, we propose a new concept of the coordination number (CN) rule to tune electrochemical compatibility of electrolytes by regulating the ion–solvent-coordinated (ISC) structure. Based on this rule, we introduced the low-coordination-number solvents (LCNSs) into the high-coordination-number solvent (HCNS) electrolytes to induce anions into the first solvation shell of Li+, forming the anion-induced ISC (AI-ISC) structure. The HCNS-LCNS electrolytes with the AI-ISC structure show enhanced reduction stability, enabling reversible lithiation/delithiation of the graphite anode. Infrared analysis and theoretical calculations confirm the working mechanism of the electrochemical compatibility in the HCNS-LCNS electrolytes based on the CN rule. Therefore, the CN rule provides guidance for the design of highly stable and multifunctional electrolytes to develop next-generation lithium secondary batteries.