Nanowire Battery - Research Paper Example

The basic electrodes in a lithium ion battery are modified by nanotechnology to improve the performance. This article intends to discuss the objectives of the nanowire battery technology. The basic features and the technology behind these batteries are discussed along with their advantages. Finally, the challenges and applications of Nano wire batteries are presented. Introduction The speed of operation of the present generation computers, other electronic gadgets and even electric cars are increasing at an exponential rate.

This presents a demand for equivalent high capacity batteries to power them with high charging and discharging rate. The batteries that power the high speed devices like laptops, mobile phones, video games and even electric cars lack these characteristics due to chemical constraints. The traditional Lithium-ion batteries transfer lithium ions from carbon anode to a metal oxide cathode. As the number of lithium ion held by one carbon ion is only one, the charge density in these batteries is low.

On the other hand, the Silicon anode has the capability to hold 4.4 lithium ions in one silicon atom. Scientists at the Stanford university (Chan. C.K. , Zhang. X. F. & Cui Y. , 2008) have explored the use of Silicon and Germanium nanowires for improved battery energy. This article intends to explore the technological insights of this Nano Wire battery technology. Objectives The existing rechargeable batteries are limited in electrical charge density as well as lifetime. The popular Lithium ion batteries used in portable electronic gadgets and cars have lithiated graphite as anode, LiPF6 as the electrolyte and the LiCoO2 as cathode.

Their major disadvantages are high production cost and lack of resources like Co for mass production. The new Nano wire battery technology, aims at eliminating the drawbacks in this Lithium ion batteries. The major objectives of this technology are to use cathodes and anodes with materials of higher energy density and to optimize the design of the batteries for higher performance. Features and Advantages The anodes used in nanowire battery were made of Silicon and Germanium nanowires (chan et al. , 2008 ). Since Silicon has low discharge potential and charge capacity of 4200 mAh/g, it is more preferred than Germanium which has a theoretical charge capacity of 1600 mAh/g.

The following Figure. 1. shows the nanowires of Silicon grown on the electrodes. Figure. 1. Silicon Nano wires grown on the electrodes. The potential advantages of the Nano Wire design are high surface to volume ratio which enables more electrode contact with the electrolyte, they provide continuous conduction of electrons within the electrode and finally, due to the fibrous design they are good in facile strain relaxation. These anodes of Silicon nanowire have ten times more storage capacity compared to the existing carbon anodes.

The most critical parameter for the safe operation of a battery is the Solid – Electrode - Interface (SEI). In nanowire batteries, the SEI formation is more when there is Lithium insertion into Silicon layers. The SEI in Silicon nanowire batteries has an inner layer of inorganic lithium compound and an outer layer of organic lithium compound. Also the voltage dependence of the SEI morphology, allows more cycles of charging and discharging. The analysis of the impedance level of these batteries shows that the impedance is due to both the process of diffusion and the