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We have synthesized a series of Li 1+ x (Ni 0.5 Mn 0.5 ) 1- x O 2 (LNMO) materials to study the influence of excess lithium ions on the structure and electrochemical behaviors of nickel-manganese-based layered compounds. The increasing content of Li + ions in the transition-metal (TM) layer leads to the departure of the follower-like clusters to Ni-rich and Mn-rich clusters. The Ni 2+ ions in the Li layer couple with adjacent transition-metal ions via strong 180° exchange interactions and moderate the local structure, which leads to magnetic clusters with finite size. Electrochemical performance shows that appropriate Ni 2+ ions could improve the cycle stability without decreasing the rate capability. Among them, Li 1.1 Ni 0.45 Mn 0.45 O 2 shows a rate capability of 76 mAh g -1 at 1000 mA g -1 and a lifespan of 300 cycles at 200 mA g -1 . This work shows that structure moderation has an essential impact on its electrochemical performance. Besides this, the crystal and magnetic combined methods we use could offer a better way of studying cathode materials.