China 4 Cell Li-ion 3.7V 18650 Battery Holder Case Plastic Lipo Battery Holder with PC Pin - China 4 Cell Li-ion 3.7V 18650 Battery Holder, with PC Pin
Battery for LAZER RUNNER Compatible 6800 mAh 4 Cell Li-Ion Battery Pack - ICR18650 4S2P - 5200
7000mah 4 cell 7.4V HC Li-Ion Battery, from Duralite, dur-7704hc - Chief Aircraft Inc.
A reflection on lithium-ion battery cathode chemistry | Nature Communications