Lithium-metal deposition/dissolution within internal space of CNT 3D matrix results in prolonged cycle of lithium-metal negative electrode

Commercialization of rechargeable Lithium (Li)-metal batteries has not been realized so far due to safety concerns and the low cycle performance. The use of a substrate with an interconnected 3D matrix is known to be an effective approach to prolong the cycle life of a Li-metal negative electrode, since the accumulation of Li deposits in the matrix can minimize the possibility of undesired dendritic growth of Li-metal. Herein, we demonstrate that a carbon nanotube (CNT)-based 3D matrix is a promising substrate material for the use of Li-metal negative electrodes. SEM and XPS analyses show that the reversible Li-metal deposition/dissolution takes place within the internal space of the CNT matrix rather than at the surface. The large electrochemical surface area and the high electrical conductivity of the matrix reduce the internal cell resistance and suppress the increases in voltage hysteresis, resulting in repetitive Li-metal deposition/dissolution. (C) 2017 Elsevier Ltd. All rights reserved.