Advanced technology

OXIS Lithium Sulfur cells are the next generation of battery technology, surpassing Li-ion which is reaching the limit of its potential. Huw Hampson-Jones, CEO of OXIS Energy describes the benefits of OXIS cells and battery technology.

The key components

  • A Lithium Metal anode
  • A Sulfur-based cathode
  • An inherently safe electrolyte protecting the lithium metal

The key strengths

  • Lightweight
  • Inherently safe
  • Full discharge
  • Cycle life
  • Cost effectiveness
  • Temperature tolerance
  • Pressure tolerance
  • Maintenance free

Lightweight

Battery systems using metallic Lithium are known to offer the highest specific energy.

Sulfur represents a natural cathode partner for metallic Li and, in contrast with conventional lithium-ion cells, the chemicals processes include dissolution from the anode surface during discharge and reverse lithium plating to the anode while charging. As a consequence, Li-S allows for a theoretical specific energy in excess of 2700Wh/kg, which is nearly 5 times higher than that of Li-ion. OXIS’s next generation lithium technology platform offers the highest energy density among lithium chemistry:

  • 400 Wh/kg already achieved at cell level

Safety

OXIS patented chemistry provides inherent safety allowing it to meet international standards concerning shock, crush, thermal stability and short circuit (UN38.3, IEC62133).

Thanks to its two key mechanisms, a ceramic lithium sulfide passivation layer and a non-flammable electrolyte, our cells can withstand extreme abuse situations such as bullet and nail penetrations with no adverse reaction.

Cycle life

OXIS Long Life Li-S cells have achieved an excellent cycle life: cells can be cycled approximately 1500 times (80% Beginning-of-Life). In the next 2 years, we expect this to reach 2500 cycles before the capacity reduces to 80% BoL.

Cost Effectiveness

Li-S production cost projections are significantly lower than Li-Ion due to lower raw material cost (i.e. Sulfur) and high energy density (less material required for same energy). This cost advantage is expected to be a key driver for widespread adoption of Li-S technology.

Temperature tolerance

The OXIS chemistry is ideally suited for deployment at high temperatures whereas most battery technologies do not tolerate high temperatures. The OXIS chemistry remains safe over 60°C and we have successfully completed thermal stability tests (for safety) at 150 ⁰C which surpasses most Li-Ion chemistries. OXIS collaborates with the British Antarctic Survey to develop cells capable of operating at -80°C.

Pressure tolerance

In the Marine Autonomous Systems (MAS) project with the National Oceanography Centre (NOC), OXIS Li-S cells have been tested up to 660 bar (6600 m equivalent water depth). The performance of the cells remained unchanged.

Full discharge

OXIS cells have a 100% available Depth-of-Discharge. This compares with Li-ion batteries which are only used across 80% (or less) of their available discharge range. OXIS cells use all their stored energy – full discharge.

Maintenance free

OXIS cells have an indefinite shelf-life, with no charging required when left for extended period. Li-ion batteries require a recharge every 3-6 months to prevent failure and often causes significant warranty issues.

Eco friendly

The OXIS Li-S chemistry is considered to have less environmental impact when compared to other technologies such as Li-ion. The Li-S cell utilises sulfur in place of heavy metals such as cobalt, which have a significant environmental impact, whereas the sulfur used in OXIS manufacture is a recycled material, a by-product of the oil industry.