Yu‐Xing Yao

The advanced lithium‐ion batteries that can tolerate zero‐volt storage (ZVS) are in high demand for implantable medical devices and spacecraft. However, ZVS can raise the anode potential, leading to Cu current collector dissolution and solid‐electrolyte interphase (SEI) degradation, especially at 37 °C. In this contribution, by quantitatively regulating the dosage of Li₆CoO₄ cathode additives, controllable potential of the working anode under abusive‐discharge conditions is demonstrated. The addition of Li₆CoO₄ keeps zero‐crossing potential (ZCP) and the potential of ZVS below 2.0 V (vs Li/Li⁺) for LiCoO₂|mesocarbon microbead cells at 37 °C. The capacity retention ratio (CRR) increases from 69.1% and 35.9% to 98.6% and 90.8% after 10 and 20 days of ZVS, respectively. The Cu dissolution and SEI degradation are effectively suppressed, while the over‐lithiated cathode exhibits high reversible capacity after ZVS. The limiting conditions of long‐term ZVS are further explored and a corresponding guide map is designed. When quantitatively regulating ZCP and the potential in ZVS, Cu dissolution, SEI degradation, and irreversible conversion of the cathode constitute the limiting conditions. This contribution designs the most reasonable potential range for ZVS protection at 37 °C, and realizes the best CRR record through precise potential regulation for the first time.

The solid electrolyte interphase (SEI) is regarded as the most important yet least understood component in Li-ion batteries. Considerable effort has been devoted to unravelling its chemistry, structure, and ion-transport mechanism; however, the nucleation and growth mode of SEI, which underlies all these properties, remains the missing piece. We quantify the growth mode of two representative SEIs on carbonaceous anodes based on classical nucleation theories and in situ atomic force microscopy imaging. The formation of inorganic SEI obeys the mixed 2D/3D growth model and is highly dependent on overpotential, whereby large overpotential favors 2D growth. Organic SEI strictly follows the 2D instantaneous nucleation and growth model regardless of overpotential and enables perfect epitaxial passivation of electrodes. We further demonstrate the use of large current pulses during battery formation to promote 2D inorganic SEI growth and improve capacity retention. These insights offer the potential to tailor desired interphases at the nanoscale for future electrochemical devices.

Lithium (Li) metal has been considered a promising anode for next‐generation high‐energy‐density batteries. However, the low reversibility and intricate Li loss hinder the widespread implementation of Li metal batteries. Herein, we quantitatively differentiate the dynamic evolution of inactive Li, and decipher the fundamental interplay among dynamic Li loss, electrolyte chemistry, and the structure of the solid electrolyte interphase (SEI). The actual dominant form in inactive Li loss is practically determined by the relative growth rates of dead Li⁰ and SEI Li⁺ because of the persistent evolution of the Li metal interface during cycling. Distinct inactive Li evolution scenarios are disclosed by ingeniously tuning the inorganic anion‐derived SEI chemistry with a low amount of film‐forming additive. An optimal polymeric film enabler of 1,3‐dioxolane is demonstrated to derive a highly uniform multilayer SEI and decreased SEI Li⁺/dead Li⁰ growth rates, thus achieving enhanced Li cycling reversibility.

Lithium (Li) metal has been considered a promising anode for next‐generation high‐energy‐density batteries. However, the low reversibility and intricate Li loss hinder the widespread implementation of Li metal batteries. Herein, we quantitatively differentiate the dynamic evolution of inactive Li, and decipher the fundamental interplay among dynamic Li loss, electrolyte chemistry, and the structure of the solid electrolyte interphase (SEI). The actual dominant form in inactive Li loss is practically determined by the relative growth rates of dead Li⁰ and SEI Li⁺ because of the persistent evolution of the Li metal interface during cycling. Distinct inactive Li evolution scenarios are disclosed by ingeniously tuning the inorganic anion‐derived SEI chemistry with a low amount of film‐forming additive. An optimal polymeric film enabler of 1,3‐dioxolane is demonstrated to derive a highly uniform multilayer SEI and decreased SEI Li⁺/dead Li⁰ growth rates, thus achieving enhanced Li cycling reversibility.

High‐energy‐density lithium (Li) metal batteries are severely hindered by the dendritic Li deposition dictated by non‐uniform solid electrolyte interphase (SEI). Despite its unique advantages in improving the uniformity of Li deposition, the current anion‐derived SEI is unsatisfactory under practical conditions. Herein regulating the electrolyte structure of anions by anion receptors was proposed to construct stable anion‐derived SEI. Tris(pentafluorophenyl)borane (TPFPB) anion acceptors with electron‐deficient boron atoms interact with bis(fluorosulfonyl)imide anions (FSI⁻) and decrease the reduction stability of FSI⁻. Furthermore, the type of aggregate cluster of FSI⁻ in electrolyte changes, FSI⁻ interacting with more Li ions in the presence of TPFPB. Therefore, the decomposition of FSI⁻ to form Li₂S is promoted, improving the stability of anion‐derived SEI. In working Li | LiNi_0.5Co_0.2Mn_0.3O₂ batteries under practical conditions, the anion‐derived SEI with TPFPB undergoes 194 cycles compared with 98 cycles of routine anion‐derived SEI. This work inspires a fresh ground to construct stable anion‐derived SEI by manipulating the electrolyte structure of anions.

High‐energy‐density lithium (Li) metal batteries are severely hindered by the dendritic Li deposition dictated by non‐uniform solid electrolyte interphase (SEI). Despite its unique advantages in improving the uniformity of Li deposition, the current anion‐derived SEI is unsatisfactory under practical conditions. Herein regulating the electrolyte structure of anions by anion receptors was proposed to construct stable anion‐derived SEI. Tris(pentafluorophenyl)borane (TPFPB) anion acceptors with electron‐deficient boron atoms interact with bis(fluorosulfonyl)imide anions (FSI⁻) and decrease the reduction stability of FSI⁻. Furthermore, the type of aggregate cluster of FSI⁻ in electrolyte changes, FSI⁻ interacting with more Li ions in the presence of TPFPB. Therefore, the decomposition of FSI⁻ to form Li₂S is promoted, improving the stability of anion‐derived SEI. In working Li | LiNi_0.5Co_0.2Mn_0.3O₂ batteries under practical conditions, the anion‐derived SEI with TPFPB undergoes 194 cycles compared with 98 cycles of routine anion‐derived SEI. This work inspires a fresh ground to construct stable anion‐derived SEI by manipulating the electrolyte structure of anions.

Lithium (Li) metal anodes hold great promise for next‐generation high‐energy‐density batteries, while the insufficient fundamental understanding of the complex solid electrolyte interphase (SEI) is the major obstacle for the full demonstration of their potential in working batteries. The characteristics of SEI highly depend on the inner solvation structure of lithium ions (Li⁺). Herein, we clarify the critical significance of cosolvent properties on both Li⁺ solvation structure and the SEI formation on working Li metal anodes. Non‐solvating and low‐dielectricity (NL) cosolvents intrinsically enhance the interaction between anion and Li⁺ by affording a low dielectric environment. The abundant positively charged anion–cation aggregates generated as the introduction of NL cosolvents are preferentially brought to the negatively charged Li anode surface, inducing an anion‐derived inorganic‐rich SEI. A solvent diagram is further built to illustrate that a solvent with both proper relative binding energy toward Li⁺ and dielectric constant is suitable as NL cosolvent.

Lithium (Li) metal anodes hold great promise for next‐generation high‐energy‐density batteries, while the insufficient fundamental understanding of the complex solid electrolyte interphase (SEI) is the major obstacle for the full demonstration of their potential in working batteries. The characteristics of SEI highly depend on the inner solvation structure of lithium ions (Li⁺). Herein, we clarify the critical significance of cosolvent properties on both Li⁺ solvation structure and the SEI formation on working Li metal anodes. Non‐solvating and low‐dielectricity (NL) cosolvents intrinsically enhance the interaction between anion and Li⁺ by affording a low dielectric environment. The abundant positively charged anion–cation aggregates generated as the introduction of NL cosolvents are preferentially brought to the negatively charged Li anode surface, inducing an anion‐derived inorganic‐rich SEI. A solvent diagram is further built to illustrate that a solvent with both proper relative binding energy toward Li⁺ and dielectric constant is suitable as NL cosolvent.

Emerging interfacial chemistry of the graphite anode in today's lithium-ion batteries paves the way to next-generation, high-performance energy storage devices.

The performance of lithium-ion battery is highly dependent on its interfacial chemistry, which is regulated by electrolytes. Conventional electrolyte typically contains polar solvents to dissociate Li salts. Here, we report a novel weakly-solvating electrolyte (WSE) that consists of a pure non-polar solvent, which leads to a peculiar solvation structure where ion pairs and aggregates prevail under a low salt concentration of 1.0 M. Importantly, WSE forms unique anion-derived interphases on graphite electrodes that exhibit fast-charging and long-term cycling characteristics. First-principles calculations unravel a general principle that the competitive coordination between anions and solvents to Li ion is the origin of different interfacial chemistries. By bridging the gap between solution thermodynamics and interfacial chemistry in batteries, this work opens a brand-new way towards precise electrolyte engineering for energy storage devices with desired properties.