Anode-free LiNiO₂ battery: a high energy density, low-cost cell design

Anode-free (AF) lithium batteries offer high energy densities and lower manufacturing cost but require improved lithium (Li) inventory management to extend cycle life. Here, we integrate polycrystalline LiNiO₂ (LNO), a high-capacity, cobalt-free cathode, into this format and demonstrate a 36% higher gravimetric energy density (stack-level) than an equivalent LNO/graphite full cell. Through a systematic variation of voltage windows, we demonstrate a cycling strategy to meaningfully improve lifetime. Implementation of an initial wide-voltage formation step (3-4.6 V, 2 cycles), followed by a reduced cycling window (3-4.1 V), significantly improves the capacity retention by establishing a Li reservoir on the anode that compensates for subsequent irreversible losses. Ex situ cryo-PFIB-SEM (PFIB-SEM: plasma focused ion beam scanning electron microscopy) cross-sections reveal a ∼28 µm Li deposit after the first charge cycle that becomes a ∼10 µm reservoir after discharge. Scaling manufacturing to pouch cell format, and operating under 1 MPa stack pressure, enabled 80% capacity retention after 80 cycles, significantly outperforming the coin cell configuration. Overall, this study demonstrates the potential of the LNO AF system, and shows that protocol optimisation alone, without the need for pre-lithiation, current collector modification, or complex electrolytes, provides a scalable route toward stable LNO AF batteries.