Applying an optimized stack pressure of 12.5 bar to commercial NMC811 lithium-ion pouch cells doubled their lifetime compared with cells held at extra-low pressure, according to researchers at the University of Cambridge. The team published the results in Nature Energy (DOI: 10.1038/s41560-026-02087-6), and Cambridge Enterprise, the university's technology transfer arm, has already filed a patent on the process.

The finding matters for R&D managers because it requires no change to electrolyte or electrode composition. The researchers deliberately tested commercial nickel manganese cobalt (NMC) pouch cells with a standard formulation, which allowed them to compare cells fairly across pressure conditions and isolate pressure as the only variable. That makes the result, in principle, transferable to existing manufacturing lines — provided the pressure can be applied repeatably and without significant error, a constraint the authors themselves flag as a condition for real-world deployment.

Instrumentation and method

To control pressure precisely, the team built a dilatometer with pneumatic bellows. The bellows act as a clamp, holding a uniform and constant pressure on the electrode stack, while a sensor detects small volume changes as the battery charges and discharges. The dilatometry data is central to the paper's mechanism work: it let the researchers track electrode thickness evolution over cycling and connect thickness, porosity and degradation mode.

"In this work we optimized how hard battery anodes and cathodes should be pushed together to maximize the lifetime of batteries," Michael de Volder of Cambridge's Institute for Manufacturing, one of the lead researchers, told Physics World. "Importantly, we also unravel which degradation mechanisms kick in if you press too hard, or not hard enough."

Measured results

The headline number: increasing stack pressure fourfold over the typical initial values used in conventional coin cells, to 12.5 bar, doubled the lifetime of the NMC811 cells. The comparison set covered five pressure points — 1.5 bar (extra-low), 3 bar (low), 6.5 bar (medium), 12.5 bar (optimal) and 37.5 bar (high) — giving the study a usefully wide pressure window rather than a single optimized point.

The degradation mechanisms differ sharply at each end of that window. At low stack pressure, cathode cracking accelerates. The researchers attribute this to a small number of particles bearing most of the mechanical load, creating localized high-stress concentrations that initiate crack propagation. Cracking in turn drives increased transition metal dissolution and excessive growth of the solid electrolyte interphase (SEI) layer.

At high stack pressure, the failure mode shifts to lithium plating on the anode. The dilatometer showed electrode thickness decreasing during initial cycling and then entering rapid growth. At the thickness minimum, the electrodes have lower porosity, which limits lithium transport, raises overpotentials and promotes plating. That plating creates "dead" lithium and shrinks the usable lithium inventory, degrading the cell faster.

The figure accompanying the paper summarizes this trade-off: balanced interparticle contact and porosity at the optimal pressure minimize mechanical degradation, while the extremes each unlock a distinct failure pathway.

Safety claims need more data

The authors are careful to separate what they measured from what they project. De Volder notes that sub-optimal pressure accelerated "certain dangerous degradation processes," and suggests pressure optimization might therefore improve battery safety — but he explicitly adds that more research is needed before drawing reliable conclusions on that point. Teams evaluating the work for portfolio decisions should treat the lifetime doubling as the measured result and the safety benefit as an open hypothesis.

The same discipline applies to the economic projections. If pressurization proves viable at scale, longer-lived batteries could raise the resale value of second-hand EVs and reduce demand for lithium mining and other critical mineral extraction — a relevant consideration given recent lithium price volatility. Those outcomes assume the same battery demand and successful scale-up, neither of which the study demonstrates. The sustainability framing is also, in part, a response to poor battery recycling rates, as de Volder makes clear:

"We carried this work out to improve the sustainability of batteries," he says. "Given that we are not very good at recycling batteries, extending the lifetime of batteries reduces the need for mining critical minerals for making new batteries and therefore improves their sustainability."

What comes next

The patent filing signals that both the research team and the university see a commercial path for the process, though no licensing partner has been announced. On next steps, de Volder says the team studied pressure optimization for one specific battery chemistry but anticipates lifetime gains in other chemistries as well — an extension that, if confirmed, would broaden the technique's value well beyond NMC811 pouch cells.