NOVELTY - A lithium ion battery (10) consists of positive electrode (20) comprising current collector (22) and active material (24), and negative electrode (30) comprising current collector (32) and active material (B) containing lithium titanate material and active material (C) containing lithium vanadate and lithium manganate. The active material (C) exhibits charging and discharging capacity below the corrosion potential of the current collector of the negative electrode and above the decomposition potential of the active material (24).    USE - Lithium ion battery. Uses include but are not limited to medical device e.g. pacemaker, cardioverter, cardiac contractility modulator, drug administering device, diagnostic recorder and cochlear implant, cellular phone, mobile phone, cordless phone and automobiles.    ADVANTAGE - The lithium ion battery can be charged or recharged even when the medical device containing the battery is implanted in a patient. Transcutaneous energy transfer can be used in which magnetic induction is used to deliver energy from outside the body to the implanted battery without the need to make direct physical contact of the implanted battery and without the need for any portion of the implant to protrude from the patient's skin. The battery having reduced volume and collector corrosion resistance is manufactured economically.    DETAILED DESCRIPTION - A lithium ion battery consists of positive electrode comprising current collector and active material, and negative electrode comprising current collector and active material (B) containing lithium titanate material and active material (C). The active material (C) exhibits charging and discharging capacity below the corrosion potential of the current collector of the negative electrode and above the decomposition potential of the active material (24). The active material (C) contains lithium vanadate (LixVO2, where x is 0.05-0.4), lithium manganate of formula: LiMxMn2-xO4, where M is metal and x is 1 or more, vanadium oxide, molybdenum oxide, titanium sulfide, tungsten oxide, molybdenum oxide and/or ruthenium oxide.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of the lithium ion battery.    Lithium ion battery (10)    Positive electrode (20)    Current collectors (22,32)    Active material (24)    Negative electrode (30)