Opportunities for disruptive advances through engineering for next generation energy storage

Throughout human history, major economic disruption has been due to technological breakthroughs. Since 1990 the energy density of lithium-ion cells has increased by a factor of four and the cost has dropped by a factor of 10. This has caused disruption to the energy industry, but advances are slowing. The manufacturing and supply chain complexity means that the next big technology will take 15 years to dominate. The academic literature charts this process of development and can be used to show what is in the pipeline. Three candidates that have had a large increase in publication count are: lithium sulphur, solid-state, and sodium-ion technology. From the level of investments in start-ups and academic publication counts, solid‑state cells are closest to maturity. To identify disruption potential, look at uncertainty in performance. Cell lifetime in lithium-ion cells indicates room for improvement. Define a new disruption metric: . Look for areas of industry that lower this metric. Thermal management is a lucrative area for improvement. Cooling the cell tabs of a 5Ah cell reduces the lifetime cost by 66%, compared to 8%/pa for 13 years relying on cost reduction. Second life applications lower the lifetime cost by using the remaining 75% of energy throughput available in a cell after use in an electric vehicle. Drop-in changes to standard manufacturing processes enable huge disruption. Electrolyte additives can increase cell life by 10 times, lowering lifetime cost by 90% in a simple manufacturing intervention

Negative curves on algebraic surfaces

We study curves of negative self-intersection on algebraic surfaces. We obtain results for smooth complex projective surfaces X on the number of reduced, irreducible curves C of negative self-intersection C^2. The only known examples of surfaces for which C^2 is not bounded below are in positive characteristic, and the general expectation is that no examples can arise over the complex numbers. Indeed, we show that the idea underlying the examples in positive characteristic cannot produce examples over the complex number field. The previous version of this paper claimed to give a counterexample to the Bounded Negativity Conjecture. The idea of the counterexample was to use Hecke translates of a smooth Shimura curve in order to create an infinite sequence of curves violating the Bounded Negativity Conjecture. To this end we applied Hirzebruch Proportionality to all Hecke translates, simultaneously desingularized by a version of Jaffee's Lemma which exists in the literature but which turns out to be false. Indeed, in the new version of the paper, we show that only finitely many Hecke translates of a special subvariety of a Hilbert modular surface remain smooth. This new result is based on work done jointly with Xavier Roulleau, who has been added as an author. The other results in the original posting of this paper remain unchanged.Comment: 14 pages, X. Roulleau added as author, counterexample to Bounded Negativity Conjecture withdrawn and replaced by a proof that there are only finitely many smooth Shimura curves on a compact Hilbert modular surface; the other results in the original posting of this paper remain unchange