context: A pre-lithiated MCMB anode (Fig. S9†) is utilized to match the LLOs cathode for assembling full cells. Since the matched capacity ratio of the anode/cathode is about 1.1 in the full cells, the specific capacity is evaluated based on the weight of the LLO cathode, while the energy density is calculated based on all the components of the full cell. The electrochemical performance of MCMB|LLO full cells is shown in Fig. 5. The full cells show specific capacities of 270 and 256 mA h g−1 at the cut-offs of 4.7 V and 4.5 V with initial coulombic efficiencies of 81.2% and 84.5%, respectively. As exhibited in Fig. 5(b–f), the full cells exhibit a rapid decay of discharge capacity with a capacity retention of only 61.2% after 100 cycles at 0.5C at the cut-off of 4.7 V. By contrast, the full cells show a much enhanced cycling stability with a capacity retention of 84.5% at the cut-off of 4.4 V after the same cycling period. Also, the full cells cycled at 4.4 V show low electrochemical polarization (Fig. S10†), corresponding to the stable discharge voltage as shown in Fig. 5(f). All the components of a typical pouch full cell are shown in Fig. S11,† and the mass fraction of the cathode in a LIB full cell reaches ∼35%. High energy densities of ∼320 and 305 W h kg−1 are achieved for the MCMB|LLO full cells at the cut-offs of 4.7 and 4.4 V, respectively. If a high-capacity Si/C anode is utilized, the energy density of the full cells can be further enhanced. Improved cycling stability of energy density is also confirmed for the full cells cycled at the cut-off of 4.4 V (Fig. 5(f)). The rate capabilities of the MCMB|LLO full cells at the cut-offs of 4.7 V and 4.4 V are illustrated in Fig. 5(d and e) and S12.† The full cells cycled at the cut-off of 4.4 V deliver reversible capacities of 204.6, 186.1, 152.0, and 125.2 mA h g−1 at the high rates of 1C, 2C, 5C and 10C, respectively, which are much higher than those of cells cycled at the cut-off of 4.7 V. Similar to half cells, the full cells exhibit improved electrochemical performance at the low cut-off of 4.4 V. The performance of MCMB|LLO full cells can be further improved by optimizing the electrolyte, capacity ratio of the anode/cathode, prelithiation and full cell design in future studies.
answer: LLOs