A group of American scientists from Argonne National Laboratory have been able to make progress in the implementation of Li-ion batteries with increased capacity. This development will be able to increase the energy capacity of the anode material by 10 times, which in the near future will give more autonomy with equal energy consumption or will allow to maintain autonomy at the current level for greater equipment productivity. A tenfold increase in the capacity of lithium batteries using red phosphorus at the same size is a reality, not a myth.
Modern Li-ion batteries use graphite as an anode. This material is stable and will not crack after thousands of discharge and charge cycles. In general, this could have been an end if not for 2 factors. The productivity of equipment is growing and energy carriers with Li-ion technology on graphite cannot cope, since the latter has a low energy capacity.
In order to gradually increase the energy capacity of Li-ion batteries, new anode materials are needed. Silicon and phosphorus are considered affordable and promising materials that do not significantly increase production costs. Each element is theoretically 10 times more energy efficient than graphite. Silicon, used as an anode in li-ion as early as 2025, promises to be commercially available worldwide. But scientists from America do not support silicon, relying on phosphorus because of the global problems of the first:
- Expansion of the material upon saturation with li-ion and reverse contraction upon recoil destroys the anode and reduces the capacity “before our eyes”;
- The Coulomb efficiency (the difference between the stored and delivered energy, the more, the better) does not meet the standards of commercial products (silicon has up to 80%, but should be over 90%).
Phosphorus, on the other hand, has shown something interesting that further progress in the design of lithium-ion batteries can catch on to.
First, the scientists implemented a composite anode using black and then red phosphorus particles. The material particles were crushed to a micrometer size. Further, they combined with the same size carbon particles. The material measured at the outlet showed a Coulomb efficiency of over 90%.
The energy efficiency of black phosphorus is higher than that of red. But, working with black phosphorus is expensive, so they decided to refuse it. Red phosphorus will be able to increase the capacity for li-ion batteries on composite anodes within an acceptable range of production costs. This combination is good and there is a need for capacious batteries on the market. Therefore, it remains to find a manufacturer who will be interested in this technology.