High Power and High Capacity 3D-Structured TiO2 Electrodes for Lithium-Ion Microbatteries

Jie Xie,Chunguang Chen,Jos F M Oudenhoven,Rüdiger-A Eichel,Peter H L Notten,Dongjiang Li

doi:10.1149/2.1141610jes

Abstract

An on-chip compatible method to fabricate high energy density TiO2 thin film electrodes on 3D-structured silicon substrates was demonstrated. 3D-structured electrodes are fabricated by combining reactive ion etching (RIE) with low pressure chemical vapor deposition (LPCVD), enabling accurate control of the aspect ratio of substrates and the subsequent deposition of TiO2 thin film electrodes onto these structured substrates. The prepared 3D-TiO2 electrodes exhibit a current-dependent increase in storage capacity of a factor up to 16 as compared to conventional planar electrodes. In addition, these 3D electrodes also reveal excellent power and cycling performance. This work demonstrates that LPCVD is capable of depositing homogeneous film electrodes on highly structured substrates and the prepared 3D-electrodes also shows significant improve in storage capacity and power density.

Highlights

Nowadays, many electronic products are becoming smart and connected
A miniaturized on-chip battery would be highly desirable for these applications, making the energy and power density per footprint area a key attribute of these batteries
It is clear that all films are homogeneous without revealing any cracks or pinholes, which is an apparent advantage of low pressure chemical vapor deposition (LPCVD) to deposit high quality thin films

Summary

Introduction

Many electronic products are becoming smart and connected. Thousands of wireless sensors united in networks collect useful data that make our lives safer and more convenient. Several reports have demonstrated that 3D-TiO2 electrodes reveal a higher footprint areal storage capacity and power performance.[17,18,20,21,22] since these methods are not directly based on Si substrate technology, integrating these 3D batteries onto chips or micro-sensors would be very challenging.

Results

Conclusion