Titanium-Based Anode Materials with Al-Doped ZnO ALD Coating for High-Performance Lithium-Ion Batteries

Abstract

In commercial lithium ion batteries, graphite is used as the most common anode material, which are easy to generate lithium dendrites, when operating at a high current rate, causing an internal short circuit and thus suffering from critical safety issues. Titanium-based anode materials are a class of alternative materials to graphite, which has a potential to offer a significant safety advantage over the graphite anode. Lithium titanate oxide (Li4Ti5O12, LTO) and titanium dioxide (TiO2) are two of the most studied titanium-based anodes because of their properties of intrinsic safety and small volume expansion. Recently our group deposited high electronic conductive Al-doped ZnO (AZO) films on the LTO and anatase TiO2 samples by atomic layer deposition (ALD). The optimum AZO-coated LTO exhibited a superior rate capability and cycling stability at 55 ℃ within a potential rage of 0.1 V to 3.0 V; the optimum AZO-coated TiO2 delivered a much higher capacity than that of the uncoated TiO2 even after 500 cycles of discharge/charge at 1 C rate (1 C = 168 mAh g-1). The coating of AZO thin films is believed to improve the conductivity of the active materials, protect the active materials from the electrolyte, and suppress the undesirable interfacial reactions between them.