Anchoring Iodine to N-Doped Hollow Carbon Fold-Hemisphere: Toward a Fast and Stable Cathode for Rechargeable Lithium–Iodine Batteries

Abstract

Rechargeable lithium-iodine batteries with abundant raw materials and low cost are promising electrochemical energy storage systems. Herein, we demonstrate that anchoring iodine to N-doped hollow carbon fold-hemisphere (N-FHS) is highly efficient to overcome slow kinetics and low stability of iodine cathode in lithium-iodine batteries. For the first time, significant effects of carbon framework architecture on the lithium storage performance of iodine cathode are studied in detail. Notably, the fold-hemisphere (N-FHS) is more effective than the similar architectures, such as hollow sphere (N-S) or hemisphere (N-HS), in modifying slow ion transport capability and fast structure deterioration. The superior property of iodine@N-FHS is associated with its highly porous structure and strong interconnection to iodine. The iodine deterioration mechanism in lithium-iodine battery is analyzed, and the deterioration processes of iodine in different carbon frameworks during cycling are investigated. This work opens a new avenue to solve the key problems in lithium-iodine batteries, allowing it an important candidate for energy storage.

Honeycomb‐like carbon materials derived from coffee extract via a “salty” thermal treatment for high‐performance Li‐I2 batteries

“…Lithium-iodine (Li-I 2 ) battery could be a possible solution for these challenges because of its high energy and power density. [11][12][13][14][15][16][17][18] Li-I 2 battery has a fast electrochemical conversion of redox pair (I − /I 3 − ) with a high theoretical specific capacity of 211 mAh•g −1 . More importantly, the dissolved redox couples (I − /I 3 − ) can eliminate the effect of the lattice barrier of solid electrode and reduce the internal resistance of traditional LIBs, delivering a highpower performance.…”

“…Generally, physical adsorption of microporous material and chemical adsorption of heteroatoms to I 2 molecules are promising strategies for addressing these challenges. 11,15,16,[22][23][24][25] Being an outstanding conductive and porous medium for fast electron transfer and rapid iodine redox reactions, N-graphene, 18 Ti 3 C 2 T x MXene, 27 and carbon nanotubes 28 have been used to fabricate the interlayer for these purposes. Additionally, they can offer large reaction interfaces for the pseudo-capacitive storage in Li-I 2 batteries.…”

“…Therefore, LIBs and SCs individually cannot meet the escalating needs of future high‐energy and high‐power appliance and equipment, such as electrical vehicles (EV) and hybrid electrical vehicles (HEV). Lithium‐iodine (Li‐I 2 ) battery could be a possible solution for these challenges because of its high energy and power density 11‐18 . Li‐I 2 battery has a fast electrochemical conversion of redox pair (I − /I 3 − ) with a high theoretical specific capacity of 211 mAh·g −1 .…”

High Energy Density CNT/NaI Composite Cathodes for Sodium‐Ion Batteries

“…The Li-iodine system (I 2 + 2Li ↔ 2LiI) has been studied for LIBs because of fast conversion of the iodine/triiodide redox pair and high reaction voltage with lithium. [10][11][12][13][14][15][16][17] Initial evidence suggests the Na-iodine system can also be used for SIBs analogously.…”

“…The very small hysteresis (0.03 V) between the charging and discharging NaI 3 /NaI redox peaks and the average working potential of 2.83 V, which is close to the thermodynamic value of 2.96 V (calculations in supporting information), are particularly promising as they indicate the electrode is operating close to its thermodynamic limits. This small hysteresis is probably due to its fast kinetics by nature [10][11][12][13][14][15][16][17] and the fact that the reaction kinetics is not limited by externally owing to high electrical conductivity of CNT and very small size of active materials coated on CNT. To study the reaction kinetics of the CNT/NaI electrodes, cyclic voltammetry was conducted at scan rates from 0.3 to 1.5 mV s -1 (Figure 3a).…”