State-of-the-art specific energy of lithium-ion cells in academic research

Research Interfaces is tracking the highest reported specific energies of different Li-ion technologies in academic literature. See below the chart for more details and relevant references. If you want to join us and stay up to date on the latest battery research, check out our Keeping Up with Batteries service.

Why is specific energy (also gravimetric energy density) so important? Because it is a metric that reflects the performance of the whole cell and is thus relevant to battery applications. It represents a critical step from academia to industry, serving as an estimate of the practical potential of a new battery technology. As such, record specific energy is difficult to achieve because it requires excellence in both science and engineering.

As of July 2020, the best example of a high-energy Li-ion cell has been reported by the Battery500 Consortium. It is a pouch cell with commercially relevant capacity (2.0 Ah) and cycle life (~350 cycles, tested at C/10 charge and C/3 discharge). The cell has a specific energy of 350 Wh/kg and is based on Li-metal anode and NMC (or NCM) cathode chemistry.

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Are these cells comparable?

Yes, partially. We are aware that the energy and capacity of each cell is influenced by its chemistry, architecture, and testing conditions. However, we include the key cell parameters in the labels and article references below, so readers can make their own judgement. This chart aims to serve as a quick insight into the state-of-the-art development of battery technologies for decisionmakers outside of academia.

Which cells do we include?

At the moment, we include two commercially relevant technologies – traditional Li-ion chemistry (with graphite-, silicon-, and carbon-based anodes) and novel Li-metal chemistry (with lithium-metal anode). We include cells that:

  • are reported in recognized peer-reviewed journals or disclosed by credible research institutions,
  • have sufficient cycling stability (>100 cycles),
  • have all (or most) components included in the energy calculations,
  • have the highest reported specific energy to date, or have demonstrated other special attributes worth highlighting.

Where is volumetric energy density (Wh/l)?

Unfortunately, energy density (also volumetric energy density) values are rarely reported in academic literature. While we understand it is a crucial metric for many applications, we just don’t currently have enough data points to plot.

Cell references

350 Wh/kg (Battery500 Consortium)
Battery500: Progress Update (US Department of Energy website)

320 Wh/kg (Tsinghua University)
A sustainable solid electrolyte interphase for high‐energy‐density lithium metal batteries under practical conditions (Qiang Zhang et al., Angewandte Chemie)

305 Wh/kg (Pacific Northwest National Laboratory)
High-energy lithium metal pouch cells with limited anode swelling and long stable cycles (Jun Liu et al., Nature Energy)

260 Wh/kg (Korea Institute of Science and Technology)
Langmuir–Blodgett artificial solid-electrolyte interphases for practical lithium metal batteries (Won Il Cho et al., Nature Energy)

381 Wh/kg (estimated) (Pacific Northwest National Laboratory)
Self-smoothing anode for achieving high-energy lithium metal batteries under realistic conditions (Jun Liu et al., Nature Nanotechnology)

230 Wh/kg (CEA Grenoble)
Practical implementation of Li doped SiO in high energy density 21700 cell (Yvan Reynier et al., Journal of Power Sources)

205 Wh/kg (Vrije Universiteit Brussel)
Electrical characterization and micro X-ray computed tomography analysis of next-generation silicon alloy lithium-ion cells (Noshin Omar et al., World Electric Vehicle Journal)

200 Wh/kg (Dalhousie University)
A wide range of testing results on an excellent lithium-ion cell chemistry to be used as benchmarks for new battery technologies (Jeff Dahn et al., Journal of The Electrochemical Society)

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