Controlling Solid–Liquid Conversion Reactions for a Highly Reversible Aqueous Zinc–Iodine Battery

Abstract

Aqueous rechargeable batteries are desirable for energy storage because of their low cost and high safety. However, low capacity and short cyclic life are significant obstacles to their practical applications. Here, we demonstrate a highly reversible aqueous zinc–iodine battery using encapsulated iodine in microporous carbon as the cathode material by controlling solid–liquid conversion reactions. We identified the factors influencing solid–liquid conversion reactions, e.g., the pore size, surface chemistry of carbon host, and solvent effect. Rational manipulation of the competition between the adsorption in carbon and solvation in electrolytes for iodine species is responsible for the high reversibility and cyclic stability. The zinc–iodine battery delivers a high capacity of 174.4 mAh g–1 at 1C, stable cyclic life over 3000 cycles with ∼90% capacity retention, and negligible self-discharge. We believe that the principles for stabilizing the zinc–iodine system could provide new insight for other conversion systems such as lithium–sulfur systems.

Halide‐Based Materials and Chemistry for Rechargeable Batteries

“…Some other approaches regarding the design of iodine‐based cathode materials to restrain the dissolution of iodine species include the incorporation of ultra‐small B 2 O 3 ‐modified carbon microtubes with abundant nanopores, reduced graphene oxide, microporous carbon, or a polymer matrix . Physical confinement and chemical adsorption are both required to restrict the iodine species at the cathode side.…”

“…Some other approaches regarding the design of iodinebased cathode materials to restrain the dissolution of iodine species include the incorporation of ultra-small B 2 O 3 -modified carbon microtubes with abundant nanopores,r educed graphene oxide,m icroporous carbon, or ap olymer matrix. [331][332][333][334] Physical confinement and chemical adsorption Figure 26. Dischargea nd charge curves of Li-iodine batteries after standing for different times at acurrent density of 0.5 C(1C= 211 mA g À1 iodine ) with three electrolytes:a )1m LiPF 6 in EC/EMC/DMC;b )1m LiTFSI in DOL/DME;c )1m LiTFSI in DOL/DME with 1wt% LiNO 3 added.…”

A Long Cycle Life, Self‐Healing Zinc–Iodine Flow Battery with High Power Density

“…[11] Also,d eposition of I 2 in the catholyte and precipitation of zinc oxides and hydroxides in the anolyte during cycling significantly decrease the stability of the electrolytes. [13] Moreover,the low conductivity of electrolytes and the low ion conductivity of the Nafion membrane in aneutral medium result in low power densities of ZIFBs.…”

“…Additionally,t he substitution of ZnI 2 with KI can effectively prevent precipitation of hydroxides and oxides of zinc in the anolyte during cycling,which has proven to be one of the most troublesome factors that negatively impact battery cycling stability. [13] Furthermore,t he porous polyolefin membrane provides amuch higher ion conductivity in aneutral environment. As ar esult, the ZIFB described herein can operate at 80 mA cm À2 with an EE of 82 %, which is much higher than currently reported Zn/I 2 systems.F urthermore,t he energy density can reach as high as 80 Wh L À1 with ac ycling life of more than 1000 cycles over 3months.M ost important, ac ell stack with a7 00 Woutput can be continuously operated for more than 300 cycles,w hich further confirms the reliability and applicability of this new-generation ZIFB.…”

Halogenid‐basierte Materialien und Chemie für wiederaufladbare Batterien

“…Einige andere Herangehensweisen bezüglich des Designs der Iod‐basierten Kathodenmaterialien zur Beschränkung der Auflösung von Iod‐Spezies beinhalten die Einbindung von ultrakleinen B 2 O 3 ‐modifizierten Kohlenstoff‐Mikroröhrchen mit zahlreichen Nanoporen, reduziertem Graphenoxid, mikroporösem Kohlenstoff oder der Polymermatrix . Sowohl physikalische Einschließung als auch chemische Adsorption werden benötigt, um die Iod‐Spezies auf der Kathodenseite zu begrenzen.…”