LiMn2O4 thin films with nano-crystals less than 100nm were successfully grown on polished stainless steel substrates at 400°C and 200mTorr of oxygen by pulsed laser deposition. A maximum discharge capacity of 62.4μAhcm−2 μm−1 cycled between 3.0 and 4.5V with a current density of 20μAhcm−2 was achieved. The effect of several overdischarge cycles was negligible, and both the effect of Jahn–Teller distortion at low potentials on capacity loss and structure instability at high potentials were effectively inhibited in this nano-crystalline film, resulting in an excellent cycling stability with a very low fading rate of capacity up to 500 cycles at 55°C.