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Work Function Tunable Titanium Carbonitride Nanostructures for High‐Efficiency, Rechargeable Li–Iodine Batteries
Author(s) -
Anju V. G.,
Austeria Muthu P.,
Sampath S.
Publication year - 2017
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201700151
Subject(s) - materials science , faraday efficiency , work function , nanostructure , chemical engineering , gravimetric analysis , redox , tin , density functional theory , titanium , nanotechnology , battery (electricity) , electrode , electrochemistry , chemistry , thermodynamics , metallurgy , computational chemistry , organic chemistry , power (physics) , physics , layer (electronics) , engineering
Present study discusses the effects of parameters like work function, adsorption energy, and density of states in tuning the electrocatalytic activity of highly stable, corrosion resistant, ceramic, titanium carbonitride nanostructures. Kelvin force microscopy reveals that the work function of titanium carbonitrides can be tuned from TiN (3.8 eV) to TiC (5.3 eV), through various TiC x N y compositions. The composition, TiC 0.7 N 0.3 , possesses a value of 4.85 eV, close to the potential of the redox couple (I 3 − /I − , 4.9 eV) with favorable adsorption characteristics. Density functional theory calculations reveal favorable interactions between TiC 0.7 N 0.3 and iodine/iodide couple. Nanostructures of TiC 0.7 N 0.3 with several micron length are synthesized and the mechanism of formation is deciphered to be based on oriented growth in one dimension. The nanostructures are very effective catalysts for I 3 − /I − redox reaction that leads to Li–I 2 batteries with superior gravimetric energy density of 447 Wh kg −1 and a high open circuit voltage of 3.3 V. The battery delivers reversible stable capacity of 254 and 160 mAh g −1 at drain currents of 2.5 and 5 mA cm −2 , respectively, with a Coulombic efficiency ≥98%. The tailored battery can hold high drain currents of 10 mA cm −2 , delivering stable capacity for ≈7000 cycles.