Home » Particle size, Zeta potential, Zetasizer

Do material scientists dream of electric bicycles?

31 May 2011 One Comment

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I’m very keen on electric bikes. In fact, I’ve built my own folding electric bike so I can easily put it in the back of the car. They seem like a cheat, but you can put in as much effort as you want, and it is much more pleasant to be sitting up and viewing the countryside than hunched sweating over the handlebars of a bike in the gym.

Battery technology is improving, with solid state technologies offering novel packaging methods, using sachets of chemicals rather than metal cans to reduce the overall weight – which on a pedal cycle is one of the prime considerations. My current 5 kg battery will take me 50 miles (80 km) on a single charge and I’m not a light passenger…

The influence of particle characterization on battery performance

The need to produce better batteries for a greener future was discussed in more detail in an earlier blog by my colleague Carl Levouger. Here I want to focus on guiding you towards evidence that demonstrates the role of particle size and zeta potential, measured using the Zetasizer of course, towards better battery performance.

A good place to start is to plug ‘particle size AND batteries AND zetasizer’ into Google Scholar and then take your pick! For the relevance of zeta potential use; ‘zeta potential AND batteries AND zetasizer’.

The powerof a battery is dependant on maximising the voltage produced, and minimising the internal resistance. For high power discharging and charging, this is a function of the polarisation concentration of the Lithium ions, which is in turn a function of the diffusion rate of the ions, and you’ve guessed it, this depends on the particle size of the ions. For some battery chemistries the particle size of the Lithium ion species would need to be as small as 15nm for the highest continuous power draw. K.M. Abraham explains this neatly in his paper: What does Electrode Particle Size have to do with High Power Lithium-Ion Batteries?

Solid-state batteries

According to Kevin Bullis in ‘Solid state batteries’, published in MIT’s Technology Review blog, this new technology is ideal for use in electric vehicles. With higher power-to-weight ratios, they may replace conventional Lithium Ion batteries in future.

Do you disagree? If so, we’d love to hear your thoughts!