The service life of over 1000 charging cycles advocates the use of LiFePO4 cells in solar and energy storage. Due to high safety, environmental compatibility, a long service life and cycle stability, the IFR cell is often used in model making, e-bikes and e-scooters.
 

Lithium iron phosphate (LiFePO4) in the size 22650 with 2000mAh

Lifetime 10x longer than Li-Ion batteries with approx. 1000 charging cycles.
High safety, environmental compatibility, a long lifetime and cycle stability speak for LiFePo4 cells.

Safety instructions:

Lithium cells may only be operated with protective electronics!
Please note that lithium cells may only be used by authorised specialist personnel.
Incorrect handling or short-circuiting may result in fire or explosion.

Other features:

Lithium iron phosphate batteries are thermally stable and are not subject to memory effect.
They work on the basis of lithium and are characterised by a high energy density.
Power density up to 3000 W/kg, higher than the conventional Li-Ion battery based on LiCoO2, thus high load capacity (continuous current draw).

Notes:

A special charger is required for charging lithium iron phosphate batteries, which charges the batteries according to a special charging procedure. (CCCV = constant current, constant voltage.) The batteries must not be charged above a voltage of 3.65 volts, otherwise there is a risk of fire and explosion. It is advantageous to charge the batteries only up to approx. 3.55 volts, as this significantly increases the service life or number of charging cycles (possibly up to double). For charging, only lithium  chargers with a charge up to 3.65V may be used. e.g..:
XTAR: VP2; 
Nitecore: D4, D2, I2, I4, SC2, SC4, UM2, UMS2, UM4, UMS4.
Enova: Gyrfalcon, All-44, All88;
SkyRC: MC-3000

Furthermore, rechargeable batteries and batteries do not belong in household waste! Please dispose of them as required by law at the municipal collection points or in the [usually green] containers provided by retailers.