P2-type layered Na0.45Ni0.22Co0.11Mn0.66O2 as intercalation host material for lithium and sodium batteries

► Layered P2-Na0.45Ni0.22Co0.11Mn0.66O2 reversibly uptakes and releases Li and Na cations. ► Electrochemical performance of sodium intercalation is better than that of lithium. ► Na0.45Ni0.22Co0.11Mn0.66O2 shows good Na-ion intercalation capacity (125 mAh g−1). ► Na0.45Ni0.22Co0.11Mn0.66O2 shows high average discharge voltage (>3.3 V). ► Na-ion insertion in Na0.45Ni0.22Co0.11Mn0.66O2 offers high charge efficiency (≥99.5%).