Review—Electrolyte and Electrode Designs for Enhanced Ion Transport Properties to Enable High Performance Lithium Batteries

Abstract

Lithium-ion batteries (LiBs) are recognized as the most rapidly growing energy storage technology. To improve the energy and power density of LiBs, tremendous progress has been made in every battery component. In this review, we focus on the investigations of electrolyte and electrode designs aimed at understanding and enhancing ion transport properties to improve the performance of LiBs. Theoretical, computational, and experimental studies of the importance of transport properties are highlighted, and the efforts to enhance the lithium transference number in organic electrolytes is discussed. We also review the significant ion transport challenges in porous electrodes and the demonstrated examples of advanced, high power/energy density electrodes. Overall, we focus on the most recent and pioneering works in terms of complex electrolytes with high transport properties and thick porous electrodes for high performance LiBs. This review intends to provide guidance for development of advanced electrolytes and electrodes for high performance LiBs through comprehensive compilation of prior understanding via experimental, computational, and theoretical points of view.

Anion chemical composition of poly(ethylene oxide)-based sulfonylimide and sulfonate lithium ionomers controls ion aggregation and conduction

“…40 Such an ion chemical composition dependence for conductivity offers new perspectives on the design of highly conductive ionomers, if the impacts of ion composition on ion conduction can be fully understood, since the current efforts in lowering polymer T g to promote conductivity have in many ways reached a limit. 16,20,21,42–46 To the authors’ knowledge, the minimum T g achieved have been 203 K for Li + conducting single-ion conductors and 187 K for Br − conducting single-ion conductors and the largest ionic conductivities achieved at room temperature have been ∼10 −5 –10 −4 S cm −1 . 21,31,47–50…”

“…18,19 Single-ion conducting polymers in which the Li-ion is the mobile cation exhibit high transference numbers due to the anion being attached to the polymer backbone. 16,[19][20][21] Dual-ion polymer electrolytes typically contain a mixture of a neutral polymer such as poly(ethylene oxide) (PEO) and salt (e.g., bis(trifluoromethane)sulfonylimide lithium salt (LiTFSI)), where cations and anions both contribute to the conductivity. 18 High transference number (B1) is expected to prevent Li dendrite formation by reducing concentration polarizations of anions that is detrimental to cell performance.…”

Covalent Organic Framework for Rechargeable Batteries: Mechanisms and Properties of Ionic Conduction

“…In a typical battery system, as shown in Figure 1b, the liquid electrolyte includes protic solvent electrolyte and aprotic solvent electrolyte, while the solid conductors can be divided into electrode material and solid-state electrolyte. [53][54][55][56][57][58][59] Besides, the ionic conduction at the interface is also an important factor affecting the battery performance, mainly including solid electrolyte interphase (SEI), cathode electrolyte interphase (CEI), and electrode/solid-state electrolyte interface. [60][61][62][63][64] In condensed materials, the ionic diffusion can be achieved by the jumps of ions with their neighbors leading to the position exchange.…”

Microstructure and mechanical properties of electrochemically cycled ice‐templated Li 4 Ti 5 O 12 sintered anodes

“…2 Inactive additives also have negative consequences on electrochemical properties, including reducing the effective electroactive area and greatly increasing ion transport restrictions. 3,4 Toward overcoming these challenges, researchers have reported electrodes free of inactive materials. One option includes the use of "sintered electrodes," where active material powder is processed and then thermally treated to remove any binders.…”

“…However, inactive materials reduce the energy density 2 . Inactive additives also have negative consequences on electrochemical properties, including reducing the effective electroactive area and greatly increasing ion transport restrictions 3,4 . Toward overcoming these challenges, researchers have reported electrodes free of inactive materials.…”