Battery electronification: intracell actuation and thermal management.

Electrochemical batteries - essential to vehicle electrification and renewable energy storage - have ever-present reaction interfaces that require compromise among power, energy, lifetime, and safety. Here we report a chip-in-cell battery by integrating an ultrathin foil heater and a microswitch into the layer-by-layer architecture of a battery cell to harness intracell actuation and mutual thermal management between the heat-generating switch and heat-absorbing battery materials. The result is a two-terminal, drop-in ready battery with no bulky heat sinks or heavy wiring needed for an external high-power switch. We demonstrate rapid self-heating (∼ 60 °C min-1), low energy consumption (0.138% °C-1 of battery energy), and excellent durability (> 2000 cycles) of the greatly simplified chip-in-cell structure. The battery electronification platform unveiled here opens doors to include integrated-circuit chips inside energy storage cells for sensing, control, actuating, and wireless communications such that performance, lifetime, and safety of electrochemical energy storage devices can be internally regulated.

A new approach to both high safety and high performance of lithium-ion batteries.

We present a novel concept to achieve high performance and high safety simultaneously by passivating a Li-ion cell and then self-heating before use. By adding a small amount of triallyl phosphate in conventional electrolytes, we show that resistances of the passivated cells can increase by ~5×, thereby ensuring high safety and thermal stability. High power before battery operation is delivered by self-heating to an elevated temperature such as 60°C within tens of seconds. The present approach of building a resistive cell with highly stable materials and then delivering high power on demand through rapid thermal stimulation leads to a revolutionary route to high safety when batteries are not in use and high battery performance upon operation.