Enhancement of Columbic Efficiency and Capacity of Li-Ion Batteries using a Boron Nitride Nanotubes-Dispersed-Electrolyte with High Ionic Conductivity

Abstract

Carbon nanotubes (CNT) are currently used as conductive additives for the electrodes to enhance the capacity of the lithium-ion batteries (LIBs), and we herein for the first time demonstrate the feasibility of boron nitride nanotubes (BNNT) as an electrolyte additive for lithium ion batteries (LIBs). The 0.9 wt % BNNT electrolyte yielded enhanced Li-ion conductivity up to 30% (∼0.87 mS/cm) and a much higher Li-ion transference number (∼0.73) compared to electrolytes without BNNT. The BNNT dispersed electrolyte (1 M LiPF6 in ethylene carbonate/dimethyl carbonate) prepared via sonication serves as a new electrolyte formulation, together with the NCM622//graphite full cell, and exhibits the highest reversible capacities of 153 mAh/g at 1 C and excellent cyclic retention over 500 cycles at high 10 C with a specific capacity of 71.5 mAh/g and a Coulombic efficiency of 99.6% compared to 125.3 mAh/g at 1 C and 40 mAh/g at 10 C with only 97.5% Coulombic efficiency without BNNT, respectively. Overall, we suggest BNNT as a new class of functional electrolyte material that resolves the major limitations of conventional carbonate-based electrolytes and is compatible for different electrolytes/electrode materials aimed at practical implementations for current as well as advanced LIBs.