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Electrolyte engineering is crucial for improving cathode electrolyte interphase (CEI) to enhance the performance of lithium‐ion batteries, especially at high charging cut‐off voltages. However, typical electrolyte modification strategies always focus on the solvation structure in the bulk region, but consistently neglect the dynamic evolution of electrolyte solvation configuration at the cathode‐electrolyte interface, which directly influences the CEI construction. Herein, we reveal an anti‐synergy effect between Li+‐solvation and interfacial electric field by visualizing the dynamic evolution of electrolyte solvation configuration at the cathode‐electrolyte interface, which determines the concentration of interfacial solvated‐Li+. The Li+ solvation in the charging process facilitates the construction of a concentrated (Li+‐solvent/anion‐rich) interface and anion‐derived CEI, while the repulsive force derived from interfacial electric field induces the formation of a diluted (solvent‐rich) interface and solvent‐derived CEI. Modifying the electrochemical protocols and electrolyte formulation, we regulate the "inflection voltage" arising from the anti‐synergy effect and prolong the lifetime of the concentrated interface, which further improves the functionality of CEI architecture. [ABSTRACT FROM AUTHOR]

The gas release within Li‐ion batteries, particularly during cycling and storage, can result in rapid performance degradation and potential safety hazards. However, this area has not garnered sufficient attention until now, primarily because the gassing information collected by typical OEMS/DEMS is quite limited and even inaccurate. Herein, for the first time, a state‐of‐the‐art on‐line GC‐BID/MS to full‐dimensionally analyze the gassing behavior within both lab‐scale coin‐type cell (in situ mode) and industry‐scale pouch‐type cell (operando mode) is originally designed/constructed. Not limited to common permanent gases (e.g. H2, CO, etc.) detected by online GC‐BID, but also complicated/various (semi‐)volatile products are identified/quantified by online GC‐MS. Based on the real‐time evolution information of water, alcohols, aldehydes, ethers, esters, and hydrocarbons, the decomposition mechanisms of electrolyte on both graphite anode and/or LCO cathode sides is further supplemented/perfected. Moreover, at the level of the device, series derivative/crosstalk reactions induced by trapped/accumulated gaseous species are unveiled in practical pouch‐cell. [ABSTRACT FROM AUTHOR]

Electrolyte engineering is a fascinating choice to improve the performance of Li‐rich layered oxide cathodes (LRLO) for high‐energy lithium‐ion batteries. However, many existing electrolyte designs and adjustment principles tend to overlook the unique challenges posed by LRLO, particularly the nucleophilic attack. Here, we introduce an electrolyte modification by locally replacing carbonate solvents in traditional electrolytes with a fluoro‐ether. By benefit of the decomposition of fluoro‐ether under nucleophilic O‐related attacks, which delivers an excellent passivation layer with LiF and polymers, possessing rigidity and flexibility on the LRLO surface. More importantly, the fluoro‐ether acts as "sutures", ensuring the integrity and stability of both interfacial and bulk structures, which contributed to suppressing severe polarization and enhancing the cycling capacity retention from 39 % to 78 % after 300 cycles for the 4.8 V‐class LRLO. This key electrolyte strategy with comprehensive analysis, provides new insights into addressing nucleophilic challenge for high‐energy anionic redox related cathode systems. [ABSTRACT FROM AUTHOR]

Aqueous ammonium ion battery is a promising sustainable energy storage system. However, the side reactions originating from electrolytes (the water decomposition and host material dissolution) preclude its practical applications. Unlike the metal‐based aqueous batteries, the idea of "ultrahigh concentrated electrolyte" is not feasible due to the strong hydrolysis of ammonium ions. Therefore, we propose an effective and sustainable strategy for the water hydrogen bond network modulation by adding sucrose into the electrolytes. The sucrose can form sucrose‐water hydrogen bond networks to break the continuous water hydrogen bond network, thereby inhibiting water decomposition significantly. Moreover, the weak hydrogen bond interaction between ammonium and sucrose facilitates rapid ion migration, leading to an improved ionic conductivity. This work presents a new electrolyte modulating strategy for the practical application of aqueous ammonium ion batteries. [ABSTRACT FROM AUTHOR]

Exfoliating graphite to graphene has attracted great attention due to the fantastic properties of graphene available for designing graphene‐based materials or devices. Besides the classic solution method, herein a unique role of TiO2 in exfoliating graphite to be graphene layers effectively is reported. As a paradigm, this discovered effect of TiO2 is significant for preparing high‐performance graphene‐modified SiOx‐based anode in lithium‐ion batteries (LIBs), in which the graphite is in situ exfoliated mechanically by TiO2 to be multilayered graphene (i.e., MLG) and then the SiOx is wrapped by the MLG to construct a SiOx/TiO2@MLG. In this case, an extremely high capacity of 1484 mAh g−1, long lifespan over 1200 cycles at 2 A g−1, as well as good performance in full LIBs (vs nickel‐rich cathode) are demonstrated. It is confirmed that the MLG can enhance electric conductivity, mitigate electrolyte decomposition, and alleviate volume effect of the SiOx effectively. This result is hard to be achieved using other kinds of metal oxide besides TiO2. It is hoped that the SiOx/TiO2@MLG is practical for pursuing LIBs with an energy density beyond 300 Wh kg−1. In addition, it is believed the ingenious strategy is applicable for designing more functional materials with greater capabilities. [ABSTRACT FROM AUTHOR]

In addressing the global climate crisis, the energy storage performance of Li‐ion batteries (LIBs) under extreme conditions, particularly for high‐energy‐density Li‐rich layered oxide (LRLO) cathode, is of the essence. Despite numerous researches into the mechanisms and optimization of LRLO cathodes under ideal moderate environment, there is a dearth of case studies on their practical/harsh working environments (e.g., pouch‐type full‐cell, high‐temperature storage), which is a critical aspect for the safety and commercial application. In this study, using pouch‐type full‐cells as prototype investigation target, the study finds the cell assembled with LRLO cathode present severer voltage decay than typical NCM layered cathode after high‐temperature storage. Further decoupling elucidates the primary failure mechanism is the over‐activation of lattice oxidized oxygen (aggravate by high‐temperature storage) and subsequent escape of oxidized oxygen species (On−), which disrupts transition metal (TM) coordination and exacerbates electrolyte decomposition, leading to severe TM dissolution, interfacial film reconstruction, and harmful shuttle effects. These chain behaviors upon high‐temperature storage significantly influence the stability of both electrodes, causing substantial voltage decay and lithium loss, which accelerates full‐cell failure. Although the anionic redox reaction can bring additional energy, but the escape of metastable On− species would introduce new concerns in practical cell working conditions. [ABSTRACT FROM AUTHOR]