Sputtering TiO2 on LiCoO2 composite electrodes as a simple and effective coating to enhance high-voltage cathode performance

Abstract

Surface coating is a key strategy in lithium-ion battery technologies to achieve a high and stable battery performance. Increasing the operation voltage is a direct way to increase the energy density of the battery. In this work, TiO 2 is directly sputtered on as-fabricated LiCoO 2 composite electrodes, enabling a controllable oxide coating on the topmost of the electrode. With an optimum coating, the discharge capacity is able to reach 160 mAh g-1 (86.5 % retention) after 100 cycles within 3.0-4.5 V at 1 C, which is increased by 40 % compared to that of the bare electrode. The high-voltage rate capability of LiCoO 2 is also remarkably enhanced after TiO 2-coating as reflected by the much larger capacity at 10 C (109 vs. 74 mAh g-1). The artificially introduced oxide coating is believed to make the LiCoO 2 electrode more resistant to interfacial side reactions at high voltage and thus minimizes the irreversible loss of the active material upon long cycling. The TiO 2 coating layer is also possible to partially react with the decomposition product of electrolyte (e.g. HF) and form a more stable and conductive interphase containing TiF x , which is responsible for the improvement of the rate capability.

Electrochemical Performance of Structure‐Dependent LiNi1/3Co1/3Mn1/3O2 in Aqueous Rechargeable Lithium‐Ion Batteries

“…However, there are still many problems that need to be solved, such as enhanced energy density, before ARLBs can be used in a wide range of applications . Commercially available LiCoO 2 possesses a high energy density, whether applied in aqueous or organic lithium‐ion systems, and has been used in many applications . However, high cost, toxicity, and insecurity of LiCoO 2 pushes researchers to look for an alternative cathode material .…”

Surface Modification of Li(Ni0.6Co0.2Mn0.2)O2 Cathode Materials by Nano-Al2O3 to Improve Electrochemical Performance in Lithium-Ion Batteries

“…LiCoO 2 has been the dominating cathode material for commercial lithium-ion batteries owing to its high capacity, stable cycling, and easy production [2]. However, cobalt in LiCoO 2 is a rare metal, expensive, and toxic, therefore alternative cathode materials such as ternary Li(Ni 1-x-y Co x Al y )O 2 and Li(Ni 1-x-y Co x Mn y )O 2 compounds with layered structures, spinel-structured LiMn 2 O 4 , olivine-structured LiMPO 4 (M = Fe, Mn, Co, Ni), and orthosilicates Li 2 MSiO 4 (M = Fe, Mn, Co), have been intensively investigated [1,3,4,5,6,7,8].…”

“…This problem could be solved by coating the surface of the cathode material with a different material. This surface modification technology was introduced for a LiCoO 2 cathode by coating with metal oxides, such as TiO 2 , Al 2 O 3 , Mg 2 TiO 4 , and NaAlO 2 [2,18,19,20]; LiNi 0.5 Mn 1.5 O 4 cathode by ZrO 2 , ZrP 2 O 7 , and AlPO 4 coating [21,22]; and Li(Ni 0.6 Co 0.2 Mn 0.2 )O 2 cathode by TiO 2 , Al 2 O 3 , and Li 2 ZrO 3 coating [23,24,25]. Among the coating processes, wet chemical processes such as sol-gel and precipitation are widely applied, which typically require 0.3–5 wt % of coating material respect to the cathode material and resulted in substantially inhomogeneous coating.…”

Ultrathin TiO2 Coating on LiCoO2 for Improved Electrochemical Performance as Li–Ion Battery Cathode

“…via different techniques had been reported ,. Among metal oxides, there are several reports on TiO 2 coated LiCoO 2 . TiO 2 is much attractive due to its low cost, good structure and thermal stability, large surface area etc .…”