TY - JOUR
T1 - Redox-Driven Spin Transition in a Layered Battery Cathode Material
AU - Watanabe, Eriko
AU - Zhao, Wenwen
AU - Sugahara, Akira
AU - Mortemard De Boisse, Benoit
AU - Lander, Laura
AU - Asakura, Daisuke
AU - Okamoto, Yohei
AU - Mizokawa, Takashi
AU - Okubo, Masashi
AU - Yamada, Atsuo
PY - 2019/1/1
Y1 - 2019/1/1
N2 -
A spin transition between high-spin (HS) and low-spin (LS) states in a solid can occur when the energies of two spin configurations intersect, which is usually caused by external perturbations such as temperature, pressure, and magnetic fields, with substantial influence to its physical and chemical properties. Here, we discover the electrochemical "redox reaction" as a new driving force to induce reversible HS-LS spin transition. Although reversible solid-state redox reaction has been thoroughly investigated as the fundamental process in battery electrode materials, coupling between redox reactions and spin transitions has not been explored. Using density functional theory calculations, we predicted the existence of redox-driven spin transition occurring exclusively for the Co
3+
/Co
2+
redox couple in layered transition-metal oxides, leading to a colossal potential hysteresis (>1 V) between the cathodic (LS Co
3+
to LS Co
2+
) and anodic (HS Co
2+
to HS Co
3+
) reactions. The predicted potential hysteresis associated with the spin transition of Co was experimentally verified for Na
x
Ti
0.5
Co
0.5
O
2
by monitoring the electrochemical potential, local coordination structure, electronic structure, and magnetic moment.
AB -
A spin transition between high-spin (HS) and low-spin (LS) states in a solid can occur when the energies of two spin configurations intersect, which is usually caused by external perturbations such as temperature, pressure, and magnetic fields, with substantial influence to its physical and chemical properties. Here, we discover the electrochemical "redox reaction" as a new driving force to induce reversible HS-LS spin transition. Although reversible solid-state redox reaction has been thoroughly investigated as the fundamental process in battery electrode materials, coupling between redox reactions and spin transitions has not been explored. Using density functional theory calculations, we predicted the existence of redox-driven spin transition occurring exclusively for the Co
3+
/Co
2+
redox couple in layered transition-metal oxides, leading to a colossal potential hysteresis (>1 V) between the cathodic (LS Co
3+
to LS Co
2+
) and anodic (HS Co
2+
to HS Co
3+
) reactions. The predicted potential hysteresis associated with the spin transition of Co was experimentally verified for Na
x
Ti
0.5
Co
0.5
O
2
by monitoring the electrochemical potential, local coordination structure, electronic structure, and magnetic moment.
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U2 - 10.1021/acs.chemmater.8b04775
DO - 10.1021/acs.chemmater.8b04775
M3 - Article
AN - SCOPUS:85063520525
JO - Chemistry of Materials
JF - Chemistry of Materials
SN - 0897-4756
ER -