In situ atomic force microscopy study of exfoliation phenomena on graphite basal planes

Fluorine Chemistry in Rechargeable Batteries: Challenges, Progress, and Perspectives

The renewable energy industry demands rechargeable batteries that can be manufactured at low cost using abundant resources while offering high energy density, good safety, wide operating temperature windows, and long lifespans. Utilizing fluorine chemistry to redesign battery configurations/components is considered a critical strategy to fulfill these requirements due to the natural abundance, robust bond strength, and extraordinary electronegativity of fluorine and the high free energy of fluoride formation, which enables the fluorinated components with cost effectiveness, nonflammability, and intrinsic stability. In particular, fluorinated materials and electrode|electrolyte interphases have been demonstrated to significantly affect reaction reversibility/kinetics, safety, and temperature tolerance of rechargeable batteries. However, the underlining principles governing material design and the mechanistic insights of interphases at the atomic level have been largely overlooked. This review covers a wide range of topics from the exploration of fluorine-containing electrodes, fluorinated electrolyte constituents, and other fluorinated battery components for metal-ion shuttle batteries to constructing fluoride-ion batteries, dual-ion batteries, and other new chemistries. In doing so, this review aims to provide a comprehensive understanding of the structure-property interactions, the features of fluorinated interphases, and cutting-edge techniques for elucidating the role of fluorine chemistry in rechargeable batteries. Further, we present current challenges and promising strategies for employing fluorine chemistry, aiming to advance the electrochemical performance, wide temperature operation, and safety attributes of rechargeable batteries.

Graphene Nano-Blister in Graphite for Future Cathode in Dual-Ion Batteries: Fundamentals, Advances, and Prospects

The intercalating of anions into cost-effective graphite electrode provides a high operating voltage, therefore, the dual-ion batteries (DIBs) as novel energy storage device has attracted much attention recently. The "graphene in graphite" has always existed in the graphite cathode of DIBs, but has rarely been researched. It is foreseeable that the graphene blisters with the intact lattice structure in the shell can utilize its ultra-high elastic stiffness and reversible lattice expansion for increasing the storage capacity of anions in the batteries. This review proposes an expected "blister model" by introducing the high elasticity of graphene blisters and its possible formation mechanism. The unique blisters composed of multilayer graphene that do not fall off on the graphite surface may become indispensable in nanotechnology in the future development of cathode materials for DIBs.

Tuning two-dimensional nanomaterials by intercalation: materials, properties and applications

2D materials have attracted tremendous attention due to their unique physical and chemical properties since the discovery of graphene. Despite these intrinsic properties, various modification methods have been applied to 2D materials that yield even more exciting results in terms of tunable properties and device performance. Among all modification methods, intercalation of 2D materials has emerged as a particularly powerful tool: it provides the highest possible doping level and is capable of (ir)reversibly changing the phase of the material. Intercalated 2D materials exhibit extraordinary electrical transport as well as optical, thermal, magnetic, and catalytic properties, which are advantageous for optoelectronics, superconductors, thermoelectronics, catalysis and energy storage applications. The recent progress on host 2D materials, various intercalation species, and intercalation methods, as well as tunable properties and potential applications enabled by intercalation, are comprehensively reviewed.

In Situ AFM Imaging of Solid Electrolyte Interfaces on HOPG with Ethylene Carbonate and Fluoroethylene Carbonate-Based Electrolytes

Chemical and morphological structure of solid electrolyte interphase (SEI) plays a vital role in lithium-ion battery (LIB), especially for its cyclability and safety. To date, research on SEI is quite limited because of the complexity of SEI and lack of effective in situ characterization techniques. Here, we present real-time views of SEI morphological evolution using electrochemical atomic force microscopy (EC-AFM). Complemented by an ex situ XPS analysis, fundamental differences of SEI formation from ethylene carbonate (EC) and fluoroethylene carbonate (FEC)-based electrolytes during first lithiation/delithiation cycle on HOPG electrode surface were revealed.