All Posts

An electric vehicle that goes farther on one charge needs a cathode that stores more energy per gram. Lithium nickel oxide (LiNiO₂, or LNO) is one of the best candidates. Its theoretical capacity is 275 mAh/g, and nickel is cheaper than cobalt. The problem is that LNO loses capacity quickly. In our cells, undoped LNO kept only about 42% of its initial discharge capacity after 100 cycles. What goes wrong? LNO is a layered material. Sheets of nickel and oxygen are stacked like

Anyone who has made milhojas (puff pastry) knows that the water in the dough matters. In the oven the water turns into steam, and the steam pushes the layers apart. Some battery materials are layered too, and the water between their layers also decides their structure. In our recent paper we studied one of them, a sodium titanate, before and after "baking" it. The result goes in the opposite direction to the pastry: when the water leaves, the layers close. What is the materia

The Volta Foundation interviewed me for its Battery Bits series. We talked about two techniques for chemical imaging: micro X-ray fluorescence (µ-XRF) and laser ablation laser ionization time-of-flight mass spectrometry (LALI-TOF-MS). Together they map the chemistry of a battery electrode fast enough to be useful in everyday R&D. The article covers my work at SLAC and my collaboration with EXUM Instruments on reference materials and multimodal diagnostics. Stanford Researcher

I just came back from Mexico, and I want to ask you a question: Do you know what a Mexican torta and a lithium-ion battery have in common? Let's think about a classic torta. It has two slices of bread. Inside, we have the ham, the cheese, some lettuce and tomatoes, the dressings like fried beans or mustard and, of course, some spicy sauce. Well, the battery also has two “caps”: positive and negative, inside there is a cathode like LiNiO2, the separator, an anode as graphite,

Before my postdoc at SLAC, I spent a few months at the Instituto de Investigaciones en Materiales (IIM) of UNAM, in Mexico City, in the group of Dr. Heriberto Pfeiffer. The materials were familiar to me. Sodium manganates such as NaMnO₂ are studied as cathodes for sodium-ion batteries. The question was not: can they clean a gas stream? Why trap carbon oxides with a ceramic? Most of our energy still comes from burning fossil fuels, and CO₂ is the main greenhouse gas they relea

From 2022 to 2026 I worked as a postdoctoral scholar at the Stanford Synchrotron Radiation Lightsource (SSRL), at SLAC, in the group of Dr. Johanna Nelson Weker. I had already been there during my Ph.D. People often ask me why battery research needs a facility the size of a synchrotron. This post is my short answer. Why a synchrotron? A synchrotron produces X-rays that are far more intense than those of a laboratory instrument, and their energy can be tuned. Intensity means s

Most lithium-ion batteries sold today use graphite as the anode. Graphite stores lithium between its carbon layers, and it needs six carbon atoms for each lithium atom. This gives a capacity of about 372 mAh/g. Silicon (Si) works differently. It forms alloys with lithium, and each Si atom can take more than four Li atoms. Its theoretical capacity is 4200 mAh/g, about ten times that of graphite. Silicon is also the second most abundant element in the Earth's crust. So why is t

A battery is a closed box. We cannot look inside while it works, at least not without a synchrotron. What we can always do is apply a voltage or a current and measure how the cell answers. Three electrochemical techniques do this in three different ways, and I use them together in almost every project. The examples below come from my work on silicon anodes. 1. Cyclic voltammetry: where do the reactions happen? In cyclic voltammetry (CV) we sweep the voltage slowly up and down