SPLithium, or Super Particle Lithium, is a valuable energy source and a currency in Let it Die. SPLithium is used for equiptment R&D and expanding the facilities in your base.
SPLithium is most commonly gained from killing Haters and Hunters in the Tower of Barbs. However, as you start to require larger amounts SPLithium, raids in the Tokyo Death Metro become a much more efficient way of obtaining it. Participating in TDM Fights will reward some when the fight ends as well. SPLithium can also be gained from Expeditions, disposing of Fighters, Lost Bags, and Login Rewards.
To increase the amount of SPLithium you can hold, you will need to upgrade your Tank by talking to Tetsuo at the TDM Metro Front. Upgrades will cost SPLithium. Upgrading it will increase capacity as well as HP, making it harder to destroy in raids.
SPLithium's main use is in upgrading equipment at Choku-Funsha. Higher tier equipment will require larger amounts of SPLithium as it continues to be upgraded.
Certain decals may increase the amount of SPLithium you gain from various drops, though this only works when it is collected from the Tower. For a full list of decals and instructions on how to obtain each of them, please refer to the main Skill Decals page.