Breaking Mass Transport Limitations by Iodized Polyacrylonitrile Anodes for Extremely Fast-Charging Lithium-Ion Batteries.

The fast-charging capability of rechargeable batteries is greatly limited by the sluggish ion transport kinetics in anode materials. Here we develop an iodized polyacrylonitrile (I-PAN) anode that can boost the bulk/interphase lithium (Li)-ion diffusion kinetics and accelerate Li-ion desolvation process to realize high-performance fast-charging Li-ion batteries. The iodine immobilized in I-PAN framework expands ion transport channels, compresses the electric double layer, and changes the inner Helmholtz plane to form LiF/LiI-rich solid electrolyte interphase layer. The dissolved iodine ions in the electrolyte self-induced by the interfacial nucleophilic substitution of PF6 - not only promote the Li-ion desolvation process, but also reuse the plated/dead Li formed on the anode under fast-charging conditions. Consequently, the I-PAN anode exhibits a high capacity of 228.5 mAh g-1 (39 % of capacity at 0.5 A g-1 delivered in 18 seconds) and negligible capacity decay for 10000 cycles at 20 A g-1 . The I-PAN||LiNi0.8 Co0.1 Mn0.1 O2 full cell shows excellent fast-charging performance with attractive capacities and negligible capacity decay for 1000 cycles at extremely high rates of 5 C and 10 C (1 C=180 mA g-1 ). We also demonstrate high-performance fast-charging sodium-ion batteries using I-PAN anodes.

Post-synthetic Fully π-Conjugated Three-Dimensional Covalent Organic Frameworks for High-Performance Lithium Storage.

A fully π-conjugated nitrogen-rich three-dimensional covalent organic framework (PYTRI-COF-2) containing both pyrazine and triazine units was prepared through a post-synthetic strategy. The imine linkages in the pre-prepared PYTRI-COF-1 were converted into heterocyclic quinoline by the Povarov reaction. The obtained PYTRI-COF-2 displayed high Li-ion storage capacity and excellent cycling stability when it was used as the lithium (Li)-ion battery electrode.

Fast-Charging Strategies for Lithium-Ion Batteries: Advances and Perspectives.

Rapid development of high-energy-density lithium-ion batteries (LIBs) enables the sufficient driving range of electric vehicles (EVs). However, the slow charging speed restricts the popularization of EVs. Commitment to fast-charging research is considered to be the key to advance the EVs strategy. This Review discusses the kinetic factors limiting the fast-charging capability at the material aspects, and summarizes the recent research strategies to achieve fast-charging performance of high-energy-density LIBs through electrode engineering, electrolyte design, and interface optimization. The increasingly important role of computational tools and advanced characterization techniques in fundamentally understanding the failure mechanism of LIBs is emphasized, and the analysis of the thermal runaway problem in the fast-charging process and the corresponding thermal optimization scheme is also involved to give the guidance for the more rational battery design. In view of these factors and strategies, some future perspectives for realizing high-performance fast-charging LIBs are proposed, which are expected to facilitate the large-scale application of fast-charging LIBs in EVs.