Hierarchically structured nanocarbon electrodes for flexible solid lithium batteries

• Published in: Nano energy 2013-09, Vol.2 (5), p.1054-1062
• Main Authors: Wei, Di, Hiralal, Pritesh, Wang, Haolan, Emrah Unalan, Husnu, Rouvala, Markku, Alexandrou, Ioannis, Andrew, Piers, Ryhänen, Tapani, Amaratunga, Gehan A.J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Battery; Carbon; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in multilayers, nanoscale materials and structures; Exact sciences and technology; Li-ion; Materials science; Nanocrystalline materials; Nanohorns; Nanoscale materials and structures: fabrication and characterization; Nanotubes; Physics; Polymer electrolyte
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2013.04.004

The ever increasing demand for storage of electrical energy in portable electronic devices and electric vehicles is driving technological improvements in rechargeable batteries. Lithium (Li) batteries have many advantages over other rechargeable battery technologies, including high specific energy and energy density, operation over a wide range of temperatures (−40 to 70°C) and a low self-discharge rate, which translates into a long shelf-life (∼10 years) [1]. However, upon release of the first generation of rechargeable Li batteries, explosions related to the shorting of the circuit through Li dendrites bridging the anode and cathode were observed. As a result, Li metal batteries today are generally relegated to non-rechargeable primary battery applications, because the dendritic growth of Li is associated with the charging and discharging process. However, there still remain significant advantages in realizing rechargeable secondary batteries based on Li metal anodes because they possess superior electrical conductivity, higher specific energy and lower heat generation due to lower internal resistance. One of the most practical solutions is to use a solid polymer electrolyte to act as a physical barrier against dendrite growth. This may enable the use of Li metal once again in rechargeable secondary batteries [2]. Here we report a flexible and solid Li battery using a polymer electrolyte with a hierarchical and highly porous nanocarbon electrode comprising aligned multiwalled carbon nanotubes (CNTs) and carbon nanohorns (CNHs). Electrodes with high specific surface area are realized through the combination of CNHs with CNTs and provide a significant performance enhancement to the solid Li battery performance. [Display omitted] •Vertically oriented CNT ‘carpets’ where grown at low temperature (520°C) directly on Al foil.•Buckled graphene sheets (CNH) produced by arc discharge were dispersed onto the CNT carpet.•The resulting hybrid electrodes were used as Li battery cathodes, showing a performance superior to CNTs alone.•The use of a solid polymer borate-ester based electrolyte was demonstrated in this system.